MAP607 Physiological Basis of Behaviour(1)-converted

In order for the basilar membrane to vibrate freely, the fluid in the lower chamber of the cochlea must have somewhere to go. Free space is provided by the round window. When the basilar membrane flexes down, the displacement of the fluid causes the membrane behind the round window to bulge out. In turn, when the basilar membrane flexes up, the membrane behind the round window bulges in. Some people suffer from a middle ear disease that causes bone to grow over the round window. Because their basilar membrane cannot easily flex back and forth, these people have a severe hearing loss. However, their hearing can be restored by a surgical procedure called fenestration (‘window making’) in which a tiny hole is drilled in the bone where the round window should be. Sounds are detected by special neurons known as auditory hair cells, located on the basilar membrane. Auditory hair cells transduce mechanical energy caused by the flexing of the basilar membrane into neural activity. These cells possess hair-like protrusions called cilia (‘eyelashes’). The ends of the cilia are embedded in a fairly rigid shelf (the tectorial membrane) that hangs over the basilar membrane like a balcony. When sound vibrations cause the basilar membrane to flex back and forth, the cilia are stretched. This pull on the cilia is translated into neural activity. The threshold for hearing in humans is 100 trillionth of a metre – we can detect a sound that is as little in strength as 100 picometres. See Figure 5.28, which compares the movement of a hair cell with the equivalent necessary to move 10 mm of the Eiffel Tower. When a mechanical force is exerted on the cilia of the auditory hair cells, the electrical charge across their membrane is altered. The change in the electrical charge causes a transmitter substance to be released at a synapse between the auditory hair cell and the dendrite of a neuron of the auditory nerve. The release of the transmitter substance excites the neuron, which transmits messages through the auditory nerve to the brain. PAIN Pain is also a perception. It is rooted in sensation, and on the biological level, in the stimulation of receptor neurons. Also, like other forms of perception, pain is sometimes experienced when there is no corresponding biological basis. In its simplest form, the pain circuit in the body can be described as follows: pain stimulates pain receptors, and this stimulus is transferred via specialized nerves to the spinal cord and from there to the brain. The pain stimulus is processed in the brain, which then sends an impulse down the spinal cord and via appropriate nerves which command the body to react, for instance by withdrawing the hand from a very hot object. Pain receptors are present everywhere in the body, especially the skin, surfaces of the joints, periosteum (the specialised lining around the bone), walls of the arteries, and certain structures in the skull. Other organs, such as the gut and muscles, have fewer pain receptors. It is interesting to note that the brain itself does not have any pain receptors at all and is therefore insensitive to pain. 100 CU IDOL SELF LEARNING MATERIAL (SLM)

Pain receptors are free nerve endings. There are three types of pain receptor stimuli: mechanical, thermal and chemical. A mechanical stimulus would be, for example, high pressure or stretching, and a thermal pain stimulus would be extreme heat or cold. Chemical pain receptors can be stimulated by chemicals from the outside world (e.g. acids), but also by certain products present in the body and released because of trauma, inflammation or other painful stimuli. Examples of these substances are bradykinins, serotonin, potassium ions and acids (such as lactic acid, which causes muscle pain after heavy exercise). Compounds called prostaglandins are released with painful stimuli, and although they don’t directly stimulate pain receptors, they do increase their sensitivity. Paracetamol and non- steroidal anti-inflammatory drugs (NSAIDs) decrease the effect of prostaglandins, that is why they work as painkillers. Paracetamol operates in the central nervous system and the NSAIDs are peripheral-acting substances. SUMMARY 1. We experience the world through our senses. Our knowledge of the world stems from the accumulation of sensory experience and subsequent learning. 2. Our senses can be broadly grouped into exteroception, for the detection of stimuli that occur outside of our body, and interception, for stimuli occurring inside of our bodies. 3. Each sensory receptor is responsive to stimuli within a specific region in space, which is known as that receptor's receptive field. The most fundamental function of a sensory system is the translation of a sensory signal to an electrical signal in the nervous system. 4. A sensory threshold is the minimum level of intensity that a stimulus must have to be detectable to the senses. 5. An absolute threshold is the smallest level of stimulus that can be detected, usually defined as at least half the time. The term is often used in neuroscience and experimental research and can be applied to any stimulus that can be detected by the human senses including sound, touch, taste, sight, and smell. 6. The cornea and lens of the eyes cast an image of the scene on the retina, which contains photoreceptors: rods and cones. 7. Cones gather visual information under illuminated conditions; rods work only when the light is very dim. 8. The energy from the light that reaches cones is transduced into neural activity when photons strike molecules of photopigment, splitting them into their two constituents. This event causes the cones to send information through the bipolar cells to the ganglion cells. 9. The axons of the ganglion cells travel through the optic nerves and form synapses with neurons in the brain. 10. Vision requires the behaviour of looking, which consists of moving our eyes and head. Small, involuntary movements keep an image moving across the photoreceptors, thus preventing them from adapting to a constant stimulus. 101 CU IDOL SELF LEARNING MATERIAL (SLM)

11. The physical dimensions of sound – amplitude, frequency and complexity – can be translated into the perceptual dimensions of loudness, pitch and timbre for sounds ranging from 30 Hz to 20,000 Hz. 12. Sound pressure waves put the process in motion by setting up vibrations in the eardrum, which are passed on to the ossicles. 13. Vibrations of the stirrup against the membrane behind the oval window create pressure changes in the fluid within the cochlea that cause the basilar membrane to flex back and forth. 14. This vibration causes the auditory hair cells on the basilar membrane to move relative to the tectorial membrane. 15. The resulting pull on the cilia of the hair cells stimulates them to secrete a transmitter substance that excites neurons of the auditory nerve. This process informs the brain of the presence of a sound. KEY WORDS/ ABBREVIATIONS • absolute threshold: the weakest amount of a stimulus that a person can detect half the time • acoustic nerve-Also known as the vestibulocochlear or auditory nerve is nerve VIII of the 12 cranial nerves. • color vision- The ability to distinguish among lights of various wavelengths. • sensory neuron-Any nerve cell that receives input from sensory receptor cells and sends information from the receptor toward the central nervous system. LEARNING ACTIVITY 1. Explain with diagram the process of interpreting visual stimuli. 2. Explain with diagram the process of interpreting audio stimuli. UNIT END QUESTIONS (MCQS AND DESCRIPTIVE) A. Descriptive Questions 1. Elaborate with the help of diagram the complexity of human eye along with its structure and functions. 2. Explain how human eye perceives brightness of the light and different colours. 102 CU IDOL SELF LEARNING MATERIAL (SLM)

3. There are certain sensations that we cannot perceive. What is factor determining the level of sensation that we can perceive. 4. Our ear plays an important role in enabling us to listening to various sounds in nature. Elaborate on this process. 5. Explain the process of human beings experiencing the sensation of pain? B. Multiple Choice Questions 1. refers to a physical feeling or perception resulting from something that happens to or comes into contact with the body. [a] Perception [b] Threshold [c] Sensation [d] Sensitivity 2. is the organization of sensory information into meaningful experiences. [a] Perception [b] Threshold [c] Sensation [d] Absolute threshold 3. is the smallest level of stimulus that can be detected. [a] Perception [b] Threshold [c] Sensation [d] Absolute threshold 4. distinguish between colour [a] Rod Cells [b] Cone Cells 103 CU IDOL SELF LEARNING MATERIAL (SLM)

[c] Retina [d] Optic Nerve 5. Pain is a [a] Perception [b] Threshold [c] Sensation [d] Sensitivity Answer 1 [c]2 [a]3 [d]4 [b]5 [a] REFERENCES • Martin, N. (2010). Psychology, (4th ed). Pearson Education Limited • Mangal, S.K. (1995). An Introduction to Psychology. Sterling Publishers Private Limited • Eynenck, M. (2014). Fundamentals of Psychology. Taylor & Francis. • Woodworth, R. S. & Marquis, D. G. (2015). Psychology a study ofmental life. Taylor & Francis. • Bernstein D. (2018) Essentials of Psychology. Cengage Learning. • Feldman, R. S. (2012) Understanding Psychology (11th ed). McGraw-Hill Education - Europe • Pinel, J.P.J. (2007). Biopsychology. New Delhi: Pearson • Rosenzweig, M. R., Leiman, A. L. & Breedlove, S. M. (1996). Biological Psychology. Sunderland, Mass: Sinauer Associates. • Green, S. (1995). Principles of biopsychology. UK: Lawrence Erlbaum Associates Ltd. • Pinel, J. P. J. (2004). Biopsychology. Boston, MA: Allyn & Bacon. • Annett, M. (1984). Left, right, hand and brain: The right shift theory. London: Lawrence Erlbaum Associates Ltd. • Bannett, T.L. (1977). Brain and Behaviour. California: Brooks/ Cole. • Leukel, F. (1985). Introduction to Physiological Psychology. New Delhi: CBS Publishers 104 CU IDOL SELF LEARNING MATERIAL (SLM)

105 CU IDOL SELF LEARNING MATERIAL (SLM)

UNIT 8 SLEEP Structure Learning Objectives Introduction Stages of sleep Patterns of Sleep Healthy Sleeping Patterns Shifting Sleep Patterns Daytime Napping Physiology of sleep? Pathology of sleep Dreams Summary Key Words/ Abbreviations Learning Activity Unit End Questions (MCQs and Descriptive) 8.11.References LEARNING OBJECTIVES After this unit, you will be able to; • Explain the concept of sleep • Describe the role of sleep and its importance • Outline the physiological changes taking place in our body when we sleep • Describe the disorders a person may suffer from that are related to sleep INTRODUCTION How important is sleep to humans? Sleep is vital to mental health. Peter Tripp found out that if a person is deprived of sleep, he or she will have psychological symptoms (although not all people have symptoms as extreme as Tripp’s). Most people think of sleep as a state of unconsciousness, punctuated by brief periods of dreaming. This is only partially correct. Sleep is a state of altered consciousness, characterized by certain patterns of brain activity and inactivity. What is consciousness? Consciousness is a state of awareness. When we discuss altered states of consciousness, we mean that people can have different levels of awareness. Consciousness can range from alertness to non-alertness. People who are fully aware with their attention focused on something are conscious of that something. A person who is not completely aware is in a different level of consciousness—an altered state of consciousness. Sleep illustrates an altered state of consciousness. Although sleep is a major part of human and animal behaviour, it has been extremely difficult to study until recently. A researcher cannot ask a sleeping person to report on the experience 106 CU IDOL SELF LEARNING MATERIAL (SLM)

without first waking the person. The study of sleep was aided by the development of the electroencephalograph (EEG), a device that records the electrical activity of the brain. Sleep is an important part of our daily routine. It is estimated that we spend about a third of our time sleeping. Quality sleep is just as important for good health as proper nutrition and physical activity. Sleep is important to many brain functions, we need sleep to learn effectively and it has been shown that a lack of sleep affects our concentration levels negatively. Evidence also shows that sleep affects almost every type of tissue and system in the body and that a chronic lack of sleep can increase the risk for non-communicable diseases such as hypertension, diabetes, cardiovascular disease and obesity. Sleep is vital to good health! We are not sure why people sleep. Sleep is characterized by unresponsiveness to the environment and usually limited physical mobility. Some people believe that sleep is restorative; it allows people to “charge up their batteries.” These people believe that sleep is a time when the brain recovers from exhaustion and stress. Other people believe it is a type of primitive hibernation: we sleep to conserve energy. Some suggest that sleep is an adaptive process; that is, in earlier times sleep kept humans out of harm’s way at night when humans would have been most vulnerable to animals with better night vision. Still other researchers believe we sleep to clear our minds of useless information. As a variation of this theory, some people believe we sleep to dream. STAGES OF SLEEP 107 CU IDOL SELF LEARNING MATERIAL (SLM)

Figure 8.1.: Patterns of Sleep Different parts of your night's sleep have different characteristics, which have lead researchers to suggest four stages. The most important source of information about the stages is the EEG (electroencephalogram). Several electrodes (small metal discs) are pasted to your scalp and the tiny electrical rhythms of resting neurons are recorded, traditionally on moving sheets of paper. Nowadays, of course, we use computers. When you are awake and busy (at least mentally), these \"brain waves\" are desynchronized, which means that they don't show a clear rhythm. They are recorded as small, rapid, and very irregular marks on the EEG paper. Underlying the jagged marks, though, is a base rhythm called beta waves, which are from 13 to 17 cycles per second (cps). Sometimes, when we are very alert yet momentarily not thinking about anything in particular, these waves become synchronized, and you can see the beta wave pattern on the EEG. When you begin to relax and empty your mind, you begin to generate alpha waves, which are from 8 to 12 cps. This is usually a very pleasant state to be in, so much so that some people have even promoted the \"alpha state\" as something akin to meditation. When you enter into stage one sleep, the waves begin to slow down, and become theta waves (4 to 7 cps). In addition, we enter into a state of flaccid paralysis of the large muscles, which means that your muscles become very relaxed and no longer respond to motor messages from the brain. Sometimes, as we move into this paralysis, our body responds as if we were falling, and we have a sudden jerk called myoclonus. After a while, we go into stage two. The EEG shows more and more slow theta waves. In addition, we occasionally see a strange wave pattern called a sleep spindle, which consists of very rapid, 15 cps, bursts of activity. After this, we enter into stage three. Now we see the very slow delta waves, which are 3 cps and slower. And finally, we enter stage four, the deepest sleep. Now the EEG shows more than 50% delta waves. Stage four is where we are most likely to find night terrors and sleep walking. Night terrors are periods of extreme emotional arousal rarely accompanied by imagery (as in dreams and nightmares). Sleep walking is where a person gets out of bed and wanders about, sometimes doing routine activities such as getting dressed. This is common among children, and parents occasionally find their kids standing at the bus stop in their pyjamas. Obviously, there is no paralysis in stage four! Usually, you don't need it. After stage four, you begin to go back up the stages, until you reach stage one again. This is sometimes called stage one emergent, and it has one particularly impressive quality: Dreams. Dreams are accompanied by movement of the eyes, which can also be recorded with the EEG machine. Because of this, stage one emergent is also called REM sleep (for \"rapid eye movement\"). Here you can see the purpose of the flaccid paralysis mentioned earlier: If we weren't paralyzed we would likely act out our dreams! 108 CU IDOL SELF LEARNING MATERIAL (SLM)

Figure 8.2.: Stages of Sleep Unfortunately for some people, the small muscles are not paralyzed – so it is stage one emergent where we see sleep talking. Sometimes, you can actually engage someone in a small conversation in this stage! It is also interesting that the fingers are not paralyzed, and so we can also see deaf people signing in their sleep. In an average night, you may go through about four or five cycles of stages, each cycle taking about 90 minutes. You usually go less deep each cycle, so that most of your deep, stage four, sleep occurs in the first half of the night. REM or dream sleep is about 20% of your total sleep, in four or five sessions. Unless you actually wake up, though, you rarely remember the first three or four dream sessions. PATTERNS OF SLEEP 8.3.1 Healthy Sleeping Patterns In healthy adults, sleep typically begins with NREM sleep. The pattern of clear rhythmic alpha activity associated with wakefulness gives way to N1, the first stage of sleep, which is defined by a low-voltage, mixed-frequency pattern. The transition from wakefulness to N1 109 CU IDOL SELF LEARNING MATERIAL (SLM)

occurs seconds to minutes after the start of the slow eye movements seen when a person first begins to nod off. This first period of N1 typically lasts just one to seven minutes. The second stage, or N2, which is signalled by sleep spindles and/or K complexes in the EEG recording, comes next and generally lasts 10 to 25 minutes. As N2 sleep progresses, there is a gradual appearance of the high-voltage, slow-wave activity characteristic of N3, the third stage of NREM sleep. This stage, which generally lasts 20 to 40 minutes, is referred to as \"slow- wave,\" \"delta,\" or \"deep\" sleep. As NREM sleep progresses, the brain becomes less responsive to external stimuli, and it becomes increasingly difficult to awaken an individual from sleep. Following the N3 stage of sleep, a series of body movements usually signals an \"ascent\" to lighter NREM sleep stages. Typically, a 5- to 10-minute period of N2 precedes the initial REM sleep episode. REM sleep comprises about 20 to 25 percent of total sleep in typical healthy adults. NREM sleep and REM sleep continue to alternate through the night in a cyclical fashion. Most slow-wave NREM sleep occurs in the first part of the night; REM sleep episodes, the first of which may last only one to five minutes, generally become longer through the night. During a typical night, N3 sleep occupies less time in the second cycle than the first and may disappear altogether from later cycles. The average length of the first NREM-REM sleep cycle is between 70 and 100 minutes; the average length of the second and later cycles is about 90 to 120 minutes. The reason for such a specific cycling pattern of NREM and REM sleep across the night is unknown. Some scientists speculate that specific sequences of NREM and REM sleep optimize both physical and mental recuperation as well as some aspects of memory consolidation that occur during sleep, but this has not been confirmed. Shifting Sleep Patterns This hypnogram shows the typical patterns of REM and NREM sleep throughout the night. Sleep patterns can be affected by many factors, including age, the amount of recent sleep or wakefulness, the time of the day or night relative to an individual’s internal clock, other behaviours prior to sleep such as exercise, stress, environmental conditions such as temperature and light, and various chemicals. For example, for the first year of life, sleep often begins in the REM state. The cyclical alternation of NREM-REM sleep in new-borns is present from birth but at 50 to 60 minutes is much shorter than the 90-minute cycles that occur in adults. Consolidated nocturnal sleep and fully developed EEG patterns of the NREM sleep stages emerge only after two to six months. Slow-wave sleep is greatest in young children and it decreases steadily with age, even if sleep duration does not change. This may be related to changes in the structure and function of the brain. Sleep history—the quantity and quality of an individual’s sleep in recent days—can also have dramatic effects on sleep patterns. Repeatedly missing a night’s sleep, an irregular sleep schedule, or frequent disturbance of sleep can result in a redistribution of sleep stages, for instance, prolonged and deeper periods of slow-wave NREM sleep. Drugs may affect sleep 110 CU IDOL SELF LEARNING MATERIAL (SLM)

stages as well. For example, alcohol before sleep tends to suppress REM sleep early in the night. As the alcohol is metabolized later in the night, REM sleep rebounds. However, awakenings also become more frequent during this time. Daytime Napping Although it is common for people in many western societies to sleep in a single consolidated block of about eight hours during the night, this is by no means the only sleep pattern. In fact, following this schedule and foregoing an afternoon nap would seem highly abnormal to many people around the world. In many cultures, particularly those with roots in tropical regions, afternoon napping is commonplace and is built into daily routines. And although the exact timing of naps is not officially scheduled, it is not uncommon for stores and government offices to close and for many activities to stop for an hour or two every afternoon. Afternoon naptime typically coincides with a brief lag in the body's internal alerting signal. This signal, which increases throughout the day to offset the body's increasing drive to sleep, wanes slightly in mid-afternoon, giving sleep drive a slight edge. Napping also typically happens during the warmest period of the day and generally follows a large mid-day meal, which explains why afternoon sleepiness is so often associated with warm afternoon sun and heavy lunches. Afternoon naps for most people typically last between 30 and 60 minutes. Any longer and there is a risk of falling into deep sleep and having a difficult time waking. Following a nap, having dissipated some of the accumulated sleep drive, many people report feeling better able to stay awake and alert in the late afternoon and evening. This increased alertness typically causes people to go to bed later and generally to sleep less at night than people who do not take naps. According to sleep experts, napping can be a good way for people who do not sleep well at night to catch up. They do caution, however, that people with insomnia may make their night- time sleep problem worse by sleeping during the day. Otherwise, they generally recommend naps for people who feel they benefit from them. PHYSIOLOGY OF SLEEP Humans spend approximately one-third of their lives in sleep. The amount of sleep a person needs to function effectively varies considerably from individual to individual and from time to time within a person’s life. New-borns spend an average of 16 hours a day sleeping, almost half of it in REM sleep. Sixteen-year-olds may spend as much as 10 to 11 hours asleep each night. Students in graduate school average 8 hours a night. Men and women who are 70 years old or older may need only 5 hours of sleep. Adults average about 25 percent of their time in REM sleep and 75 percent in NREM sleep. Although the amount of sleep a person needs may vary, it does appear that everyone sleeps and that both types of sleep are important to normal functioning. 111 CU IDOL SELF LEARNING MATERIAL (SLM)

Respiratory system During NREM sleep, there is a decrease in respiratory drive and a reduction in the muscle tone of the upper airway leading to a 25% decrease in minute volume and alveolar ventilation and a doubling of airway resistance accompanied by a small (0.5 kPa) increase in PaCO2 and decrease in PaO2. Hyper carbic and hypoxic ventilatory drives are reduced compared with wakefulness. The breathing pattern is regular except at the transition from wakefulness into sleep when brief central apnoea’s are common. During REM sleep there is a further decrease in hypercarbia and, particularly, hypoxic ventilatory drives. The breathing pattern is irregular especially during phasic REM sleep. The loss of skeletal muscle tone in REM sleep affects the intercostal and other muscles which stabilise the chest wall during inspiration. In infants, this may be seen as paradoxical movement of the rib cage and abdomen. In adults, there may be maldistribution of ventilation and impaired ventilation–perfusion matching with consequent arterial hypoxaemia. In normal subjects, this is unimportant but it may be very important in patients with chronic lung disease or abnormalities of the thoracic (e.g. kyphoscoliosis). The great majority of patients with impaired respiratory function will be at their worst during REM sleep. Cardiovascular system Blood pressure decreases during NREM and tonic REM sleep but may increase above waking values during phasic REM sleep. Cardiac output is generally decreased during all sleep phases. Systemic vascular resistance (SVR) and the heart rate are both reduced during NREM and tonic REM sleep and increased during phasic REM sleep. Central nervous system Cerebral blood flow (CBF) increases by 50–100% above the level of resting wakefulness during tonic REM sleep and is even greater during phasic REM sleep. Cerebral metabolic rate, oxygen consumption and neuronal discharge rate are reduced during NREM sleep but increased above resting values during REM sleep. The autonomic nervous system shows a general decrease in sympathetic tone and an increase in parasympathetic tone, except in phasic REM sleep. Renal system the glomerular filtration rate and filtration fraction are reduced and ADH secretion is increased resulting in a low volume concentrated urine. Endocrine system The secretion of several hormones is directly linked to the sleep/wake cycle. Melatonin is released from the pineal gland under the control of the supra-chiasmatic nuclei (SCN) in a 4– 5 h pulse, usually beginning at the onset of darkness (~9 pm). The pulse is inhibited or delayed by exposure to bright light in the evening. It is best regarded as being permissive of sleep (‘opening the gate to sleep’) rather than as a hypnotic, as it is possible to maintain wakefulness during this period. Growth hormone is mostly secreted during the first episode of SWS, particularly during puberty. Prolactin concentrations also increase shortly after sleep onset and decrease with 112 CU IDOL SELF LEARNING MATERIAL (SLM)

wakefulness. Sleep phase delay delays secretion of both of these hormones. The secretion of cortisol decreases with the onset of sleep and reaches a trough in the early hours of the morning and a peak just after waking. Temperature control In contrast to anaesthesia, thermoregulation is maintained during sleep. However, the shivering threshold is decreased and body core temperature decreases by about 0.5°C in humans and 2°C in hibernating mammals. Body temperature is linked to the circadian rhythm and reaches its nadir at about 3 am. Thermoregulation is quite good in human infants compared with other species. PATHOLOGIES OF SLEEP Sleep is an active state essential for mental and physical restoration. Sometimes, though, we may have problems falling asleep or have problems during sleep. These sleep disorders may interfere with our quality of life and personal health, as well as endanger public safety because of their role in industrial or traffic accidents. Insomnia The most common sleep pathology is simple lack of sleep! Most people need from 7 to 9 hours a night, and yet relatively few people actually get that. Teenagers typically need about 9 hours, and that slowly decreases over your lifetime. Older people usually need about 7 hours. Of course, sleep requirements differ for different people, just like, say, nutritional requirements, but people tend to underestimate their needs. It is believed that 80% of college students are seriously sleep deprived! Everyone has had a sleepless night at one time or another—a night where nothing you do brings the calm, soothing peace you want. Some people have sleep problems like this all the time, and they rarely get more than an hour or two of uninterrupted sleep a night. Insomnia— a prolonged and usually abnormal inability to obtain adequate sleep—has many causes and takes many forms. Some people cannot sleep at night because of anxiety or depression. Overuse of alcohol or drugs can also cause insomnia. The consequences are clear: You become increasingly irritable; Your attention span, your memory, and your ability to learn things diminishes; You have an increased chance of accidents. Physically, you are more likely to develop blood pressure and heart problems; Your immune system's effectiveness diminishes; And you age more quickly, ending with a shorter lifespan! Some people seem to have a hard time getting the sleep they need. This is called insomnia, and from 10 to 15% of the population suffers from it at any one time. For most people, the causes are not hard to find: Too much stress and anxiety; too much caffeine (found in coffee, tea, chocolate, and many soft drinks); other stimulants; the REM rebound (excessive dreaming) effect that comes from using alcohol or sleeping pills; and the schedule changes 113 CU IDOL SELF LEARNING MATERIAL (SLM)

involved in shift work, distance travelling, and daylight savings time. Most people who have insomnia can find significant relief if they address these issues! Narcolepsy Another disorder, narcolepsy, is characterized by a permanent and overwhelming feeling of sleepiness and fatigue. Other symptoms include unusual sleep and dream patterns, such as dreamlike hallucinations or a feeling of temporary paralysis. People with narcolepsy may have sleep attacks throughout the day. The sleep attacks are accompanied by brief periods of REM sleep. Victims of narcolepsy may have difficulties in the area of work, leisure, and interpersonal relations and are prone to accidents. Sleep Apnoea The sleep disorder sleep apnoea causes frequent interruptions of breathing during sleep. One of the most common symptoms is a specific kind of snoring that may occur hundreds of times during the night. Each snoring episode lasts 10 to 15 seconds and ends suddenly, often with a physical movement of the entire body. A blockage of the breathing passages actually causes the snoring; during this time the victim is in fact choking—the flow of air to the lungs stops. The episode ends when low levels of oxygen or high levels of carbon dioxide in the blood trigger breathing reflexes. Sleep apnoea affects about 1 in 100 Americans, occurring most often among older people. People suffering from this disorder may feel listless, sleepy, and irritable during the day. Whereas insomnia is caused by mental stress, sleep apnoea is usually caused by a physical problem that blocks the airway, such as enlarged tonsils, repeated infections in the throat or middle ear, or obesity. These conditions may cause the muscles at the base of the tongue to relax and sag repeatedly. An extremely rare disorder – .05% of the population – is narcolepsy. This is a neurological problem that causes the person to suddenly fall asleep at odd moments, sometimes frequently throughout the day. This may sound amusing, but it is in fact both dangerous and debilitating. Not so rare – 4% of the population, including myself – is sleep apnoea. Apnoea means \"not breathing\" during sleep, which is, as you can imagine, not a good thing. People with sleep apnoea can stop breathing as many as 600 times a night. When that happens, the brain wakes up, the person gasps for air, and then falls asleep again. This means that you get very little deep sleep, if any, and the effects are similar to the ones mentioned for lack of sleep above. After a while, people with sleep apnoea begin to fall asleep during the day at highly inconvenient times, such as while driving. It is also thought to be a leading immediate cause of night-time heart attacks. Nightmares and Night Terrors Frightening dreams—nightmares—occur during the dream phase of REM sleep. A nightmare may frighten the sleeper, who will usually wake up with a vivid memory of a movielike dream. On the other hand, night terrors occur during Stage IV sleep (usually within an hour 114 CU IDOL SELF LEARNING MATERIAL (SLM)

after going to bed). A night terror may last anywhere from five to twenty minutes and involve screaming, sweating, confusion, and a rapid heart rate. The subject may suddenly awake from sleep or have a persistent fear that occurs at night. Subjects usually have no memory of night terrors. Sleepwalking and Sleep Talking A disorder in which a person is partly, but not completely, awake during the night is sleepwalking. That person may walk or do other things without any memory of doing so. Sleepwalking is a disorder associated with children, although some adults may sleepwalk. Most children who sleepwalk do not have emotional problems and will outgrow it. This disorder has been linked to stress, fatigue, and the use of sedative medicines. Sleepwalking may also be inherited. It is usually harmless; however, it may become dangerous if sleepwalkers fall or otherwise injure themselves—their movements are often clumsy. It is not dangerous to wake sleepwalkers. Sleep talking is a common sleep disruption. Most people talk in their sleep more than they realize because they do not remember talking during sleep. Sleep talking can occur in either REM or NREM sleep. It can be a single word or a longer speech. Sometimes sleep talkers pause between sentences or phrases as if they are carrying on a conversation with someone else. You can even engage a sleep talker in a conversation sometimes. Like sleepwalking, sleep talking is harmless. DREAMS As we come closer to wakefulness during these cycles, we are able to develop memories of the randomfirings of neural restoration, just as we would be of perceptual events if we were completely awake. Perhaps the hippocampus, which is responsible for translating memories from \"working storage” into \"long term storage” (from immediate awareness into memory). And so we are aware of these sequences of firings, and remember the experience well enough to relate them to our friends. It has been an idea for a very long time that dreams have special meaning. Freud, of course, made this a centrepiece for his therapy. He distinguished between the manifest content (the apparent or surface meaning) and the latent content (the deeper, symbolic meaning), and he believed that a psychiatrist could interpret dreams to discover a patient's deepest needs and concerns, ones that would be too uncomfortable to confront, even in one's dreams! Over the last century, though, we have become quite sceptical of this idea. I am basically sceptical, and sometimes refer to dreams as \"brain poop,” also known in more professional circles as day residue. But I would add that dreams often seem to centre around our \"issues\" – and thereby can provide us with some leads as to what our issues are. If one dreams about anxiety-provoking things, it seems reasonable to believe that you are suffering from anxiety. If there are certain scenarios in your dreams that cause you that anxiety, perhaps those are issues for you. I, for example, frequently dream about being criticized or evaluated or humiliated in front of an audience. That certainly makes sense for me. I also dream quite a bit about moving from one house to another. Although I have lived 115 CU IDOL SELF LEARNING MATERIAL (SLM)

in my present home for over 30 years, as a kid I moved frequently. So my dreams make sense, not only as day residue, but as indicators of my psychological history. SUMMARY 1. Sleep is the balm that soothes and restores after a long day. 2. Sleep is largely driven by the body’s internal clock, which takes cues from external elements such as sunlight and temperature. 3. There are five stages of sleep during the sleep cycle. Scientists categorized the stages of sleep based on the characteristics of the brain and body during sleep. Stage 1,2,3, and 4, are categorized as ‘non-REM sleep’, and the fifth stage, is REM sleep. 4. Generally, brainwave frequencies and amplitudes from an electroencephalogram (EEG) are used to differentiate the different stages of sleep, along with other biologic rhythms including eye movements (EOG) and muscle movements (EMG). 5. During REM sleep, study participants reported both intense dream vividness and improved memory of dreams which occurred during that phase, which suggests that dreaming typically occurs REM sleep 6. The body’s natural sleep-and-wake cycle is reasonably attuned to a 24-hour period. 7. Perturbations in the sleep cycle are disruptive to the functioning of many body systems. 8. Learning, memory, stamina, general health, and mood are all affected by sleep duration and quality. 9. For many people, sleep is elusive or otherwise troubled. In fact, most people, at some point in their lives, experience difficulty falling asleep or staying asleep. 10. Potential consequences of consistently poor sleep include obesity, cardiovascular disease, and diabetes. Sleep deprivation can also affect judgement and mental acuity. 11. Sleep needs differ from person to person and across different age groups. 12. One person may need eight full hours, while another can function with less sleep. 13. Insomnia's a type of sleep disorder where somebody has trouble falling asleep or wakes up throughout the night. 14. Narcolepsy, including excessive daytime sleepiness (EDS), often culminating in falling asleep spontaneously but unwillingly at inappropriate times. 15. Sleep apnoea refers to obstruction of the airway during sleep, causing lack of sufficient deep sleep, often accompanied by snoring. 16. Sleep paralysis, characterized by temporary paralysis of the body shortly before or after sleep. Sleep paralysis may be accompanied by visual, auditory or tactile hallucinations. 17. Sleepwalking or somnambulism, engaging in activities normally associated with wakefulness (such as eating or dressing), which may include walking, without the conscious knowledge of the person 18. Night terror, Pavor nocturnus, sleep terror disorder, an abrupt awakening from sleep with behaviour consistent with terror. 19. The good news is that the treatment of sleep disorders is rapidly progressing. 116 CU IDOL SELF LEARNING MATERIAL (SLM)

KEY WORDS/ ABBREVIATIONS • consciousness: a state of awareness, including a person’s feelings, sensations, ideas, and perceptions • insomnia: the failure to get enough sleep at night in order to feel rested the next day • narcolepsy: a condition characterized by suddenly falling asleep or feeling very sleepy during the day • nightmares: unpleasant dreams night terrors: sleep disruptions that occur during Stage IV of sleep, involving screaming, panic, or confusion • REM:(rapid eye movement) A quick, unpredictable movement in which the two eyes are coordinated as if they were looking at something, which occurs with eyelids closed during a light stage of sleep and is associated with dreaming. • REM sleep: A period of relatively light sleep characterized by quick, unpredictable movement of the eyes in which the two eyes are coordinated as if they were looking at something, which occurs with eyelids closed during a light stage of sleep and is associated with dreaming. • sleep apnoea: a sleep disorder in which a person has trouble breathing while asleep • sleep walking: walking or carrying out behaviours while asleep LEARNING ACTIVITY 1. Sleep affects attention and concentration. However there are certain jobs where one needs to stay awake for long hours. What is the impact of lack of sleep? 2. Have you experienced lack of sleep at any point in recent period? How did it affect your efficiency the next day? UNIT END QUESTIONS (MCQS AND DESCRIPTIVE) A. Descriptive Questions 1. We sleep so that we get take on other tasks with a fresh start. Explain the importance of 2.Not everyone has a peaceful and normal sleep. Explain the various sleep disorder or pathologies that people can suffer from. 3. Our bodily functions change when we sleep. Explain these changes in detail. 117 CU IDOL SELF LEARNING MATERIAL (SLM)

4. Our sleep is divided in REM and nREM sleep. Elaborate in detail how are the changes in our brain activity in the brain measured? 5. We dream during certain parts or time of sleep. Explain the sleep cycle and occurrence of dream. B. Multiple Choice Questions 1. Which sleep disorder involves unusual movements, emotions, and behaviours while sleeping? [a] Narcolepsy [b] Sleep Walking [c] Insomnia [d] Parasomnia 2. Which of the following occur while we sleep? [a] The heart rate increases. [b] Levels of ghrelin will increase. [c] Breathing becomes more rapid and shorter [d] The brain enters a state of altered consciousness 3. Which of the following statements is correct? [a] Nightmares usually occur in REM sleep while night terrors usually occur in non-REM sleep. [b] Because they are common, nightmares are not considered a parasomnia. [c] Most people remember night terrors but not nightmares. [d] Nightmares are typically more intense than night terrors. 4. refers to lack of sleep [a] Narcolepsy [b] Sleep Walking 118 CU IDOL SELF LEARNING MATERIAL (SLM)

[c] Insomnia [d] Parasomnia 5. is characterized by a permanent and overwhelming feeling of sleepiness and fatigue. [a] Narcolepsy [b] Sleep Walking [c] Insomnia [d] Parasomnia Answer 1 [d]2 [d]3 [a]4 [c]5 [a] REFERENCES • Martin, N. (2010). Psychology, (4th ed). Pearson Education Limited • Mangal, S.K. (1995). An Introduction to Psychology. Sterling Publishers Private Limited • Eynenck, M. (2014). Fundamentals of Psychology. Taylor & Francis. • Woodworth, R. S. & Marquis, D. G. (2015). Psychology a study ofmental life. Taylor & Francis. • Bernstein D. (2018) Essentials of Psychology. Cengage Learning. • Feldman, R. S. (2012) Understanding Psychology (11th ed). McGraw-Hill Education - Europe • Pinel, J.P.J. (2007). Biopsychology. New Delhi: Pearson • Rosenzweig, M. R., Leiman, A. L. & Breedlove, S. M. (1996). Biological Psychology. Sunderland, Mass: Sinauer Associates. • Green, S. (1995). Principles of biopsychology. UK: Lawrence Erlbaum Associates Ltd. • Pinel, J. P. J. (2004). Biopsychology. Boston, MA: Allyn & Bacon. • Annett, M. (1984). Left, right, hand and brain: The right shift theory. London: Lawrence Erlbaum Associates Ltd. • Bannett, T.L. (1977). Brain and Behaviour. California: Brooks/ Cole. 119 CU IDOL SELF LEARNING MATERIAL (SLM)

• Leukel, F. (1985). Introduction to Physiological Psychology. New Delhi: CBS Publishers 120 CU IDOL SELF LEARNING MATERIAL (SLM)

UNIT 9 AROUSAL AND BIOLOGICAL RHYTHM Structure Learning Objectives Introduction Concept General Properties of Circadian Rhythms Human Circadian Rhythms The body Circadian The timing of Sleep Disruptions in Circadian Rhythm Summary Key Words/ Abbreviations Learning Activity Unit End Questions (MCQs and Descriptive) References LEARNING OBJECTIVES After this unit, you will be able to; • Explain the concepts of wakefulness or arousal • Understand the biological rhythms in our body • Elaborate on the areas governed by biological rhythms • Describe the factors responsible for sleep disturbances • Enlist the factors causing disruptions in circadian rhythms INTRODUCTION Many biological functions wax and wane in cycles that repeat each day, month, or year. Such patterns do not reflect simply an organism’s passive response to environmental changes, such as daily cycles of light and darkness. Rather, they reflect the organism’s biological rhythms, that is, its ability to keep track of time and to direct changes in function accordingly. Biological rhythms that repeat approximately every 24 hours are called circadian rhythms (from the Latin circa, for around, and dies, for day) (61) (figure 3-l). Biological clocks are an organism’s innate timing device. They’re composed of specific molecules (proteins) that interact in cells throughout the body. Biological clocks are found in nearly every tissue and organ. Researchers have identified similar genes in people, fruit flies, mice, fungi, and several other organisms that are responsible for making the clock’s components. 121 CU IDOL SELF LEARNING MATERIAL (SLM)

CONCEPT Affect arousal is the state of being activated, either physiologically or psychologically, and is one dimension of our affective response to emotional stimuli. Psychological characteristics of arousal include feelings of vigour, energy, and tension. Physiological symptoms of arousal include increased heart rate and blood pressure, among other changes. In the context of psychology, arousal is the state of being physiologically alert, awake, and attentive. Arousal is primarily controlled by the reticular activating system (RAS) in the brain. The RAS is located in the brain stem and projects to many other brain areas, including the cortex. Circadian rhythms are physical, mental, and behavioural changes that follow a daily cycle. They respond primarily to light and darkness in an organism's environment. Sleeping at night and being awake during the day is an example of a light-related circadian rhythm. Circadian rhythms are found in most living things, including animals, plants, and many tiny microbes. The study of circadian rhythms is called chronobiology. Human functions, ranging from the production of certain hormones to sleep and wakefulness, demonstrate circadian rhythms. This chapter summarizes the basic properties of circadian rhythms and addresses the following questions: • How are circadian rhythms generated? • How are they influenced by the environment? • What specific human functions display circadian rhythms? • What implications do these rhythms have for health and performance? • How can circadian rhythms be manipulated? GENERAL PROPERTIES OF CIRCADIAN RHYTHMS Circadian rhythms display several important characteristics. First, circadian rhythms are generated by an internal clock, or pacemaker (9,124). Therefore, even in the absence of cues indicating the time or length of day, circadian rhythms persist. The precise length of a cycle varies somewhat among individuals and species. Although organisms generate circadian rhythms internally, they are ordinarily exposed to daily cycles in the environment, such as light and darkness. The internal clock that drives circadian rhythms is synchronized, or entrained, to daily time cues in the environment (figure 3-2). Animal research has shown that only a few such cues, such as light-dark cycles, are effective entraining agents (12). In fact, the light-dark cycle is the principal entraining agent in most species, and recent research suggests that it is very powerful in synchronizing human circadian rhythms. The sleep wake schedule and social cues may also be important entraining agents in humans. .- An entraining agent can actually reset, or phase shift, the internal clock (12). Depending on when an organism is exposed to such an agent, circadian rhythms may be advanced, delayed, 122 CU IDOL SELF LEARNING MATERIAL (SLM)

or not shifted at all. This variable shifting of the internal clock is illustrated in a phase response curve (PRC) (figure 3-3). PRCs were first derived by exposing organisms housed in constant darkness to short pulses of light (40,65,125). The organisms were isolated from all external time cues. When light pulses were delivered during the portion of the organism’s internal cycle that normally occurs during the day (therefore called subjective day), they had little effect on circadian rhythms. In contrast, when light pulses were delivered late during the organism’s night-time, circadian rhythms were advanced. Light pulses delivered early during subjective night delayed circadian rhythms. Several factors make it difficult to identify time cues that can reset the internal clock. First, there is no way to examine the function of the circadian pacemaker directly. The pacemaker’s activity can only be evaluated through the circadian rhythms it drives, but unfortunately such functions are subject to other influences. Environmental stimuli may alter a particular circadian rhythm without disturbing the pacemaker at all. For example, going to sleep causes a temporary lowering of body temperature, without shifting the circadian cycle. Second, a function that exhibits a circadian rhythm may be controlled by both the circadian pacemaker and other systems in the body. For example, the timing and quality of sleep are controlled by circadian rhythms and other factors. Finally, classical techniques used to evaluate the pacemaker in animals and to generate a PRC involve complete isolation from all time cues (e.g., constant darkness) for several days, a difficult approach in human studies. Alternative methods for evaluating potential entraining agents in humans have been devised (see later discussion). HUMAN CIRCADIAN RHYTHMS Have you ever noticed that there are certain times of the day when you are more alert or more tired? People seem to have an internal biological clock that regulates the sleep-wakefulness cycle. Blood pressure, heart rate, appetite, secretion of hormones and digestive enzymes, sensory sharpness, and elimination processes all follow circadian rhythms (Hrushesky, 1994). A circadian rhythm is a biological clock that is genetically programmed to regulate physiological responses within a time period of 24 or 25 hours. Circadian rhythms operate even when normal day and night cues are removed. For example, we usually standardize our sleep patterns according to the light of day and dark of night; yet experimenters who have lived for months at a time in the depths of a cave have still maintained a rhythm to their behaviours. Without any environmental cues, people maintained their circadian rhythms on about a 24- to 25-hour cycle. Researchers have determined that humans have a circadian cycle of approximately 24.18 hours (Czeisler et al., 1999). Circadian rhythms do not control our sleep cycles; the environment and the 24-hour day control our cycles. Thus, when you miss sleep, this disruption becomes very apparent. Some travellers experience jet lag. This occurs when their internal circadian rhythms do not match the external clock time. For example, when you travel from New York to Moscow, your body 123 CU IDOL SELF LEARNING MATERIAL (SLM)

is on a different time clock when you reach Moscow. You may feel tired and disoriented. What do you do to cure jet lag? It usually takes about one day for each hour of time change to reset your circadian clock. Consider the following reported data: the frequency of heart attacks peaks between 6 a.m. and noon; asthma attacks are most prevalent at night (96); human babies are born predominantly in the early morning hours. While these patterns do not necessarily indicate that the events are driven by the circadian pacemaker, they do suggest temporal order in the functioning of the human body. This temporal organization appears to be beneficial; the human body is prepared for routine changes in state, such as awakening each morning, rather than simply reacting after shifts in demand In addition, these regular cycles in the body present considerations for diagnosis of health problems and for the timing of medical treatment Although daily fluctuations in various human functions have been documented for more than a century, that does not prove that they are controlled by the circadian pacemaker. Not until individuals were examined in temporal isolation could human circadian rhythms be verified. The first studies sequestering humans from all time cues were reported in the early 1960s (10). During the course of these and other studies, which lasted days, weeks, and even months, individuals inhabited specially designed soundproof and lightproof rooms that excluded any indication of the time of day, such as clocks, ambient light, or social interactions. In this temporal vacuum, individuals were instructed to sleep and eat according to their bodies’ clocks. These studies indicated that daily fluctuations in some human functions are generated by an internal clock (35,192). While these studies of humans isolated from time cues provide insight into the operation of the human circadian pacemaker, the approach presents difficulties; it is time-consuming and expensive, and it is difficult to recruit subjects for extended study. Alternative methods have been developed for evaluating human circadian rhythms, and these are discussed in subsequent sections. The Body Circadian Several hormones are secreted in a cyclic fashion (181). The daily surge of prolactin and growth hormone, for example, appears to be triggered by sleep (182,183). Sex hormones are secreted at varying levels throughout the day, the pattern of secretion reflecting the fertility, reproductive state, and sexual maturity of the individual. Secretions of glucose and insulin, a hormone important for regulating the metabolism of glucose, also exhibit circadian rhythms. Glucose concentrations in the blood peak late at night or early in the morning has important clinical implications. For example, (181), and insulin secretion peaks in the afternoon (118). The secretion of cortisol, a steroid hormone important for metabolism and responses to stress, fluctuates daily, peaking in the very early morning hours and falling to a negligible amount by the end of the day (181). Besides its use as a marker for the internal pacemaker, the circadian rhythm of cortisol secretion may drive other rhythms in the body and blood tests used to diagnose suspected excess cortisol production will be most sensitive during the evening. Also, cortisol-like steroid hormones used therapeutically to treat asthma and allergies and to suppress the 124 CU IDOL SELF LEARNING MATERIAL (SLM)

immune system, are best administered in the morning, when they interfere least with the body's own cortisol production. Circadian rhythms in cardiovascular function have long been recognized. Indicators of heart and blood vessel function that demonstrate daily rhythms of the respiratory system. Which Respir rhythms include blood pressure, heart rate, blood volume and flow, heart muscle function, and responsiveness to hormones (84). The daily fluctuations in cardiovascular function are further illustrated by symptoms of disease. Data have shown that abnormal electrical activity in the heart and chest pains peak at approximately 4 a.m. in patients suffering from coronary heart disease (189,190). As stated earlier, the number of heart attacks has been shown to peak between 6 a.m. and noon (1 17,140). These temporal characteristics of cardiovascular disease indicate the importance of careful timing in their assessment, monitoring, and treatment (120). The widely recognized pattern of night-time increases in asthma symptoms highlights the circadian tory functions are responsible for nocturnal asthma symptoms? Exposure to allergy-producing substances, the respiratory system’s responsiveness to compounds that can initiate an asthma attack, daily changes in the secretion of certain hormones, cells in the lung and blood that may be important mediators of asthma, and the recumbent position have all been suggested as possible mechanisms (16,163). The prevalence of asthma attacks at night has led to drug treatment approaches that take circadian rhythms into account. Other organ systems also reveal circadian fluctuations. Kidney function and urine formation vary over the course of a 24-hour period; there are daytime peaks in the concentrations of some substances in the urine (sodium, potassium, and chloride) and night- time peaks in others (phosphates and some acids) (78). Urine volume and pH also peak during the day. Immune system and blood cell functions cycle daily, as do cell functions in the stomach and intestinal tract The Timing of Sleep Daily cycles of sleep and wakefulness form the most conspicuous circadian rhythm among humans. Traditionally, about 8 hours each night are devoted to sleep. While neither the function of sleep nor how it is regulated is completely understood, it is clear that sleep is a basic requirement that cannot be denied very long. Even a modest reduction in sleep leads to decrements in performance, especially at night. Furthermore, when deprived of a night or more of sleep, individuals can find sleep impossible to resist, especially in monotonous situations, and they experience brief episodes of sleep, called microsleeps (45,104). Classic studies indicate that sleep is not a homogeneous state (42,75). Polysomnography, the measurement of electrical activity in the brain, eye movement, and muscle tone, has revealed distinct stages of sleep (table 3-l). During stages 1 through 4, sleep becomes progressively deeper. In stages 3 and 4, which constitute slow wave sleep (SWS), the eyes do not move, heart rate and respiration are slow and steady, and muscles retain their tone but show little movement. Dreams are infrequent. As sleep continues, dramatic changes occur: brain activity appears similar to that seen during wakefulness, heart rate and respiration increase and 125 CU IDOL SELF LEARNING MATERIAL (SLM)

become erratic, dreams are vivid and frequently reported, and the eyes move rapidly. This stage of sleep is rapid eye movement (REM) sleep. Typically, cycles of non-REM sleep (stages 1 through 4) and REM sleep repeat every 90 to 100 minutes throughout the course of a night’s sleep. When synchronized to the 24-hour day, the timing of sleep usually bears a characteristic relationship to the environment and to other circadian rhythms in the body. In general, humans retire for sleep after dark, when body temperature is falling. Morning awakening coincides with an upswing in body temperature. With the exception of an occasional afternoon lull (box 3-C), wakefulness continues throughout the day, and body temperature reaches its zenith during the late afternoon. Studies of humans isolated from all time cues have unveiled several characteristics about the timing of the sleep-wake cycle and the circadian pacemaker. In isolation, circadian rhythms are approximately 25 hours long (figure 3-7). While the sleep-wake and body temperature cycles are a similar length at first, their relationship gradually changes, until body temperature decreases during wakefulness and increases during sleep. Human Performance Physiological variables such as body temperature, hormone levels, and sleep are not the only human functions that exhibit circadian rhythms. Human performance, including psychological processes and mental functions, also exhibits circadian fluctuations (26). Diverse components of human performance, including memory, reaction time, manual dexterity, and subjective feelings of alertness, have been dissected experimentally to ascertain when they peak during the course of a day and how they are affected by circadian rhythm disruption. 9.5 DISRUPTIONS IN CIRCADIAN RHYTHM The common types of circadian rhythm sleep disorders include: Delayed Sleep Phase Disorder: If you have this sleep disorder, you go to sleep and wake up more than two hours later than what is typically considered a normal sleep-wake cycle. For example, you're a “night owl” who may not be able to fall asleep until 2 a.m. or later, but then sleep in until as late as 3 p.m. Other common features of delayed sleep phase disorder are: • You're often most alert, productive and creative late at night. • If forced to get up early, you are sleepy during the day. • You're often perceived as lazy, unmotivated, or a poor performer who is always late for morning responsibilities. • Is most commonly seen in adolescents and young adults. 126 CU IDOL SELF LEARNING MATERIAL (SLM)

• May run in families. Advanced Sleep Phase Disorder: If you have this sleep disorder, you fall asleep in the early evening (6 p.m. to 9 p.m.) and wake up in the early morning (2 a.m. to 5 a.m.). Other common features of advanced sleep phase disorder are: • You typically complain of early morning awakening or insomnia and are sleepy in the late afternoon or early evening. • Is most commonly seen in the middle age and older adults. • May run in families. Jet Lag: If you have this sleep disorder, your body’s internal clock has been disturbed from long air travel time to a destination that is two or more time zones different from your home. This sleep-wake cycle disruption makes it difficult to adjust and function in the new time zone. Eastward travel is more difficult than westward travel because it is easier to delay sleep than to advance sleep. Common features of jet lag are: • Change in appetite. • Changes in gastrointestinal (stomach and bowel) function. • General tiredness. • General feeling of discomfort or uneasiness and mood disturbance. Shift Work Disorder: You may have this sleep disorder if you frequently rotate shifts or work at night. These work schedules conflict with your body’s natural circadian rhythm, making it difficult to adjust to the change. Shift work disorder is identified by a constant or recurrent pattern of sleep interruption that results in insomnia or excessive sleepiness. Other common features of shift work disorder are: • Ongoing tiredness. • General feeling of discomfort or uneasiness, mood disorder. • Gastrointestinal problems. • Decreased sex drive. Other health risks include increased risk of alcohol and substance abuse, weight gain, high blood pressure, heart disease and breast and endometrial cancer. This sleep disorder is most commonly seen in people who have night or early morning shifts. Irregular sleep-wake rhythm: This sleep disorder has an undefined sleep-wake cycle. You may take several naps during a 24-hour period. Symptoms include ongoing (chronic) 127 CU IDOL SELF LEARNING MATERIAL (SLM)

insomnia, excessive sleepiness or both. This disorder is more commonly seen in people with neurological conditions such as dementia, in nursing home residents, in children with intellectual disabilities and in those with traumatic injuries to the brain. Non-24-hour sleep-wake syndrome: If you have this sleep disorder, you keep your same length of sleep and awake time, but your “internal clock” is longer than 24 hours. When this is the case, the actual sleep-wake cycle changes every day, with the time being delayed one to two hours each day. This disorder occurs most commonly in blind people. Circadian Rhythm Disorder Treatments Your treatment for circadian rhythm disorder will depend on your specific condition. The goal is to fit your sleep pattern into a schedule that matches up with your lifestyle. Treatments may include: • Bright light therapy. You reset your rhythm by being around a bright light for a certain time each day. • Sleep hygiene. You’ll learn how to improve your circadian rhythm with changes to your bedtime routine or sleep environment. • Chronotherapy. You slowly adjust your bedtime until it reaches the time you want. • Lifestyle changes. Things like scheduling naps, being careful about your exposure to light, and avoiding caffeine or nicotine for some time before bed can help. • Medication. Melatonin, stimulants, or hypnotics can change your sleep-wake cycle. SUMMARY 1. The natural cycle of physical, mental, and behavior changes that the body goes through in a 24-hour cycle. 2. Circadian rhythms are mostly affected by light and darkness and are controlled by a small area in the middle of the brain. 3. They can affect sleep, body temperature, hormones, appetite, and other body functions. 4. Abnormal circadian rhythms may be linked to obesity, diabetes, depression, bipolar disorder, seasonal affective disorder, and sleep disorders such as insomnia. 5. Circadian rhythm is sometimes called the “body’s clock.” 6. A circadian rhythm is a roughly 24 hour cycle in the physiological processes of living beings, including plants, animals, fungi and cyanobacteria. 7. In a strict sense, circadian rhythms are endogenously generated, although they can be modulated by external cues such as sunlight and temperature. 8. Circadian rhythms are important in determining the sleeping and feeding patterns of all animals, including human beings. 9. There are clear patterns of brain wave activity, hormone production, cell regeneration and other biological activities linked to this daily cycle. 128 CU IDOL SELF LEARNING MATERIAL (SLM)

KEY WORDS/ ABBREVIATIONS • biological clock-An inferred mechanism of mind which explains the capacity of organisms to follow predictable cycles in their lives, sometimes without external time cues. Mechanisms governing daily cycles of sleep and wakening are the best known biological clocks. • biological rhythm- AnyRhythms are noted in areas such as breathing, sleeping, eating, arousal level, sexual activity, menstruation, and mood. Daily, or circadian, rhythms are the best studied but biological rhythms occur in both short- and long- duration activities. • Rhythm- The rhythm of an utterance is the way its constituent parts are timed with respect to each other. LEARNING ACTIVITY 1. After an international flight, most of us experience a phenomenon call jet lag. What are the different aspects of jet lag? 2. What are the general principles of circadian rhythm? UNIT END QUESTIONS (MCQS AND DESCRIPTIVE) A. Descriptive Questions 1. Our body has an in build clock that carries out certain functions regularly. Explain what it is call and what are its functions? 2. Just like seasonal cycles, our body has innate rhythmic cycles. Write a note on these cycles and the areas it governs? 3. People working in shifts, have difficulty in maintaining their biological clock. Do you agree with this? Explain why. 4. Explain what changes you feel when you travel into place with a completely different time zone. 5. How is sleep disrupted when you work in shifts? B. Multiple Choice Questions 1. predictable pattern in an organism’s functioning over time. 129 CU IDOL SELF LEARNING MATERIAL (SLM)

[a] Biological Clock [b] Sleep Cycle [c] Biological Rhythm [d] Rhythm 2. is an organism's innate timing device. [a] Biological Clock [b] Sleep Cycle [c] Biological Rhythm [d] Rhythm 3. A biological rhythm is best defined as: [a] A heartbeat of an animal [b] The growth of a plant or animal [c] The cyclical activity of an animal [d] A change over time 4. The most common biological rhythm is the circadian rhythm, or the: [a] Nocturnal/diurnal cycle [b] Rest-activity cycle [c] Daily cycle [d] Reproductive cycle 5. Our sleep-wake cycle follows a(n) . [a] Biological Clock [b] Sleep Cycle [c] Circadian Rhythm 130 CU IDOL SELF LEARNING MATERIAL (SLM)

D) Rhythm Answer 1 [c] 2 [a] 3 [c] 4 [b] 5 [c] REFERENCES • Martin, N. (2010). Psychology, (4th ed). Pearson Education Limited • Mangal, S.K. (1995). An Introduction to Psychology. Sterling Publishers Private Limited • Eynenck, M. (2014). Fundamentals of Psychology. Taylor & Francis. • Woodworth, R. S. & Marquis, D. G. (2015). Psychology a study ofmental life. Taylor & Francis. • Bernstein D. (2018) Essentials of Psychology. Cengage Learning. • Feldman, R. S. (2012) Understanding Psychology (11th ed). McGraw-Hill Education - Europe • Pinel, J.P.J. (2007). Biopsychology. New Delhi: Pearson • Rosenzweig, M. R., Leiman, A. L. & Breedlove, S. M. (1996). Biological Psychology. Sunderland, Mass: Sinauer Associates. • Green, S. (1995). Principles of biopsychology. UK: Lawrence Erlbaum Associates Ltd. • Pinel, J. P. J. (2004). Biopsychology. Boston, MA: Allyn & Bacon. • Annett, M. (1984). Left, right, hand and brain: The right shift theory. London: Lawrence Erlbaum Associates Ltd. • Bannett, T.L. (1977). Brain and Behaviour. California: Brooks/ Cole. • Leukel, F. (1985). Introduction to Physiological Psychology. New Delhi: CBS Publishers 131 CU IDOL SELF LEARNING MATERIAL (SLM)

UNIT 10 MOTIVATION AN EMOTION Structure Learning Objectives Introduction Motivation Biological Needs Physiology of reinforcement Optimum–level theory Emotion Central and Peripheral Mechanism The role of Amygdala Left-right frontal asymmetry The orbitofrontal cortex Summary Key Words/ Abbreviations Learning Activity Unit End Questions (MCQs and Descriptive) References LEARNING OBJECTIVES After this unit, you will be able to; • Identify the physiological factors involved in motivation • Identify the physiological factors involved in emotion • Explain the basic emotions experienced by humans • Evaluate the different theoretical explanations to motivation INTRODUCTION Although all psychology is concerned with what people do and how they do it, research on motivation and emotion focuses on the underlying whys of behaviour. Motivation includes the various psychological and physiological factors that cause us to act a certain way at a certain time. We see Kristin studying all weekend while the rest of us hang out, and since we know she wants to go to law school, we conclude that she is motivated by her desire to get good grades. We see Miko working after classes at a job he does not like, and since we know he wants to buy a car, we conclude that he is motivated to earn money for the car. Movies often have motives or emotions as their central theme. On the street, you hear words like anger, fear, pain, starving, and hundreds of others describing motives and emotions. Conceptions of motivation in psychology are in many ways similar to those expressed in everyday language. 132 CU IDOL SELF LEARNING MATERIAL (SLM)

Because motivation cannot be observed directly, psychologists, like the rest of us, infer motivation from goal-directed behaviour. Behaviour is usually energized by many motives that may originate from outside of us or inside of us. Psychologists explain motivation and why we experience it in different ways. We will discuss instinct, drive-reduction, incentive, and cognitive theories of motivation. MOTIVATION Motivation includes two types of phenomenon. First, stimuli that were previously associated with pleasant or unpleasant events motivate approach or avoidance behaviours. For example, if something reminds you of an interesting person you met recently, you may try to meet that person again by consulting your mobile and sending a message. Secondly, being deprived of a particular reinforce increases an organism’s preference for a particular behaviour. Besides obvious reinforcers such as food or water, this category includes more subtle ones. For example, after spending a lot of time performing routine tasks, we become motivated to go for a walk or meet with friends.Motivation affects all categories of behaviour. Biological needs Biological needs can be potent motivators. To survive, we need air, food, water, various vitamins and minerals, and protection from extremes in temperature. Complex organisms possess physiological mechanisms that detect deficits or imbalances associated with these needs and regulatory behaviours that bring physiological conditions back to normal. Examples of regulatory behaviours include eating, drinking, hunting, shivering, building a fire and putting on a warm coat. This process of detection and correction, which maintains physiological systems at their optimum value, is called homeostasis (‘stable state’). Deficits or imbalances motivate us because they cause us to perform the appropriate regulatory behaviours. A regulatory system has four essential features: the system variable (the characteristic to be regulated), a set point (the optimum value of the system variable), a detector that monitors the value of the system variable, and a correctional mechanism that restores the system variable to the set point. A simple example of such a regulatory system is a room where temperature is regulated by a thermostatically controlled heater. The system variable is the air temperature of the room, and the detector for this variable is a thermostat. The thermostat can be adjusted so that contacts of a switch will close when the temperature falls below a pre-set value (the set point). If the room cools below the set point, the thermostat turnsthe heater on, which warms the room. The rise in room temperaturecauses the thermostat to turn the heater off. Becausethe activity of the correctional mechanism (heatproduction) feeds back to the thermostat andcauses it to turn the heater off, this process iscalled negative feedback. Negative feedback isan essential characteristic of all regulatory systems. The drive reduction hypothesis was the earliest attemptto explain the nature of motivation and reinforcement.This theory stated that biological needs, caused by deprivationof the 133 CU IDOL SELF LEARNING MATERIAL (SLM)

necessities of life, are unpleasant. Thephysiological changes associated with, say, goingwithout food for several hours produce anunpleasant state called hunger. Hunger serves as adrive, energising an organism’s behaviour. The organismthen engages in behaviours that in the past have obtainedfood. Not all drives are based on homeostasis, on biologicalneeds like the ones for food and water. The most obviousexample is the drive associated with sexual behaviour. Anindividual can survive without sexual behaviour; but thesex drive is certainly motivating, and sexual contact iscertainly reinforcing. Similarly, most organisms placed ina featureless environment will soon become motivated toseek something new; they will work at a task that givesthem a view of the world outside. The drive reduction hypothesis of reinforcement hasfallen out of favour for two primary reasons. The first isthat drive is almost always impossible to measure. Forexample, suppose you obtain pleasure from watching a setof colour slides taken by a friend while on holiday. According to the drive reduction hypothesis, your‘exploratory drive’ or ‘curiosity drive’ is high, and lookingat holiday slides reduces it, providing reinforcement. Orconsider a woman who enjoys listening to music. Whatdrive induces her to turn on her iPod? What drive isreduced by this activity? There is no way to measure ‘drive’in either of these examples and confirm that it actuallyexists; thus, the hypothesis cannot be tested experimentally. The second problem is that if we examine our ownbehaviour we find that most events we experience as reinforcing are also exciting, or drive-increasing. Thereason a roller-coaster ride is fun is certainly notbecause it reduces drive. The same is true forskiing, surfing or viewing a horror film. Figure 10.1.: An example of a regulatory system. Likewise, an interesting, reinforcing conversation is onethat is exciting, not one that puts you to sleep. Andpeople who engage in prolonged foreplay and sexualintercourse do not view these activities as unpleasantbecause they are accompanied by such a high level ofdrive. In general, the experiences we really want to repeat(that is, the ones we find reinforcing) are those thatincrease, rather than decrease, our level of arousal. 134 CU IDOL SELF LEARNING MATERIAL (SLM)

Physiology of reinforcement To understand the nature of reinforcement we mustunderstand something about its physiological basis. Oldsand Milner (1954) discovered quite by accident that electricalstimulation of parts of the brain can reinforce ananimal’s behaviour. For example, rats will repeatedlypress a lever when the brain is electrically stimulated. The neural circuits stimulated by this electricity arealso responsible for the motivating effects of natural reinforcerssuch as food, water or sexual contact, and ofdrugs such as heroin, alcohol and cocaine. Almost allinvestigators believe that the electrical stimulation of thebrain is reinforcing because it activates the same systemthat is activated by natural reinforcers and by drugs thatpeople commonly abuse. The normal function of thissystem is to strengthen the connections between the neuronsthat detect the discriminative stimulus (such as thesight of a lever) and the neurons that produce the operantresponse (such as a lever press). The electrical brain stimulationactivates this system directly. Researchers have discovered that an essential componentof the reinforcement system consists of neuronsthat release dopamine as their transmitter substance.Thus, all reinforcing stimuli appear to trigger the releaseof dopamine in the brain. Optimum-level theory Although events that increase our level of arousal are oftenreinforcing, there are times when a person wants nothingmore than some peace and quiet. In this case, avoidance ofexciting stimuli motivates our behaviour. In an attempt to find acommon explanation for both positive and negative reinforcement,some psychologists have proposed theoptimum-level hypothesis of reinforcement and punishment:when an individual’s arousal level is too high, lessstimulation is reinforcing; when it is too low, more stimulationis desired (Hebb, 1955; Berlyne, 1966). Berlynehypothesised two forms of exploration: diversive explorationis a response to under stimulation (boredom) thatincreases the diversity of the stimuli the organism tries tocome in contact with; specific exploration is a response tooverstimulation (usually because of a specific need, such aslack of food or water) that leads to the needed item,thereby decreasing the organism’s drive level. Figure 10.2.: The drive reduction hypothesis of motivation and reinforcement. The hypothesis that organisms seek an optimum level of arousal is certainly plausible. Any kind of activity, even the most interesting and exciting one, eventually produces satiety; 135 CU IDOL SELF LEARNING MATERIAL (SLM)

something that was once reinforcing becomes bothersome. Presumably, participation in an exciting behaviour gradually raises an organism’s arousal above its optimum level. However, the logical problem that plagues the drive reduction hypothesis also applies to the optimum- level hypothesis. Because we cannot measure an organism’s drive or arousal, we cannot say what its optimum level should be. Thus, the optimum-level hypothesis remains without much empirical support. EMOTION Most psychologists who have studied emotion have focused on one or more of the following questions: What kinds of situations produce emotions? What kinds of feelings do people say they experience? What kinds of behaviours do people engage in? What physiological changes do people undergo in situations that produce strong emotions? What exactly is an emotion? The word ‘emotion’ comes from Latin and means ‘to move’ or ‘to stir up’. In general terms, emotion is used by psychologists to refer to a display of feelings that are evoked when important things happen to us. Emotions are relatively brief and occur in response to events having motivational relevance (or to their mental re-creation, as when we remember something embarrassing that we did in the past and experience the feelings of embarrassment again). Emotions are the consequence of events that motivate us. When we encounter reinforcing or punishing stimuli, stimuli that motivate us to act, we express and experience positive or negative emotions. The nature of the emotions depends on the nature of the stimuli and on our prior experience with them. Basic Emotions Charles Darwin (1872) suggested that humanexpressions of emotion have evolved from similar expressionsin other animals. He said that emotionalexpressions are innate, unlearned responses consisting ofa complex set of movements, principally of the facialmuscles. Thus, a man’s sneer and a wolf’s snarl are biologicallydetermined response patterns, both controlledby innate brain mechanisms, just as coughing and sneezingare. Some of these movements resemble thebehaviours themselves and may have evolved from them.For example, a snarl shows one’s teeth and can be seen asan anticipation of biting. Darwin performed what was probably the first cross-culturalstudy of behaviour. He obtained evidence for hisconclusion that emotional expressions were innate byobserving his own children and by corresponding withpeople living in various isolated cultures around the world.He reasoned that if people all over the world, no matterhow isolated, show the same facial expressions of emotion,these expressions must be inherited instead of learned. Thelogical argument goes like this. When groups of people areisolated for many years, they develop different languages.Thus, we can say that the words that people use are arbitrary;there is no biological basis for using particularwords to represent particular concepts. 136 CU IDOL SELF LEARNING MATERIAL (SLM)

However, if facial expressions are inherited, they should take approximately the same form in people from all cultures, despite their isolation from one another. And Darwin did, indeed, find that people in different cultures used the same patterns of movement of facial muscles to express a particular emotional state. Of the basic emotions that we experience most often, it has been argued that sadness and happiness are the two most common. Recent research, however, suggests that we may experience happiness more often than was originally thought. Studies also suggest that the degree of positive mood that we exhibit in our facial expression may correlate with other expressions of positive behaviours in our lives. The Controversies in Psychological Science section below reviews this research. The Biology of Emotion Perhaps one way of determining whether an emotion is basic or not is by observing the neural machinery activated by these so-called basic emotions. If these emotions are distinct then it follows that different brain regions or pathways might mediate them. In animal research, much of the work on understanding the neural correlates of emotion has focused on fear because this emotion is easy to condition in the laboratory. Evidence from animal work and from studies of brain-damaged humans suggests that the amygdala is an important structure for the recognition and expression of fear. Other neuropsychological evidence suggests that other brain regions may also be involved in different types of emotion. All emotional responses contain three components: behavioural, autonomic and hormonal. The behavioural component consists of muscular movements that are appropriate to the situation that elicits them. For example, a dog defending its territory against an intruder first adopts an aggressive posture, growls and shows its teeth. If the intruder does not leave, the defender runs towards it and attacks. Autonomic responses – that is, changes in the activity of the autonomic nervous system – facilitate these behaviours and provide quick mobilisation of energy for vigorous movement. As a consequence, the dog’s heart rate increases, and changes in the size of blood vessels shunt the circulation of blood away from the digestive organs towards the muscles. Hormonal responses reinforce the autonomic responses. The hormones secreted by the adrenal glands further increase heart rate and blood flow to the muscles and also make more glucose available to them. One of the more important neurotransmitters for emotion is dopamine. When we experience even a slight lift in our mood – or positive affect – the increase is accompanied by an increase in dopamine in two of the major pathways that send dopamine projections to the brain. This does not mean to say that no dopamine was being carried along these pathways in the first place – there are levels of dopamine in the brain, even at rest – but it does mean that a change in behaviour resulted in an increase in these levels. 137 CU IDOL SELF LEARNING MATERIAL (SLM)

CENTRAL AND PERIPHERAL MECHANISM 10.4.1. The role of the amygdala Neuroimaging data suggest that the amygdala is relatively more involved than other brain regions in the perception of fear-related material. Morris et al. (1996) reported that not only did activation increase in the left side of the amygdala when individuals were watching fearful facial expressions but they also found that this activation was greater when the facial expression was more intense. Other fMRI and PET studies have confirmed this activation in the amygdala during the perception of fear in facial expression Patients with amygdala damage are significantly poor at identifying social (hostility, friendliness) or cognitive (pensiveness) expressions in faces, although they make judgements about the physical appearance of the faces (Shaw et al., 2005). Patients with damage to the right frontal lobe were poor at interpreting social expressions that were negatively hued, regardless of which part of the frontal lobe was damaged. The amygdala’s role in emotion does not appear to be tied to recognising or generating negative emotion. Viewing positive stimuli has also been found to be associated with a significant increase in activation in the left side of the amygdala; this activation also extends to other brain areas known to be involved in drug addiction and reward (Hamann et al., 2002). Watching diseased and mutilated bodies stimulated both sides of the amygdala (but little beyond it). The notion that the amygdala is active when encoding and retrieving positive memories suggests that its role here may be due to its role in remembering positive events. That said, the amygdala has many parts (and parts that PET may not have been sensitive enough to measure), and Hamann et al. suggest that different regions within the structure may play different roles. The amygdala is not the only region to be involved in mediating human emotional response. Perceiving the meaning of social situations is obviously more complex than perceiving individual stimuli, such as the expression of fear on people’s faces; it involves experiences and memories, inferences and judgements. These skills are not localised in any one part of the cerebral cortex, although research does suggest that one region of the brain – the orbitofrontal cortex – appears to play a special role. 10.4.2 The orbitofrontal cortex The orbitofrontal cortex (OFC) is located at the tip of the frontal lobes. It covers the part of the brain just above the orbits – the bones that form the eye sockets – hence the term ‘orbitofrontal’. The orbitofrontal cortex receives information from the sensory system and from the regions of the frontal lobes that control behaviour. Thus, it knows what is going on in the environment and what plans are being made to respond to these events. It also communicates extensively with the limbic system, which is known to play an important role in emotional reactions. In particular, its connections with the amygdala permit it to affect the activity of the amygdala, which, as we saw, plays a critical role in certain emotional responses. 138 CU IDOL SELF LEARNING MATERIAL (SLM)

Neuroimaging studies implicate the orbitofrontal cortex in emotion. One experiment compared those brain regions that were activated during pleasant or neutral touch, smell and taste (Francis et al., 1999). Participants had their hands stroked by either a velvet glove or a piece of wood as their brain activity was monitored. The pleasant touch (velvet) was associated with significantly greater activation in the orbitofrontal cortex than was the neutral touch (wood). The more intense touch (the neutral wood) was associated with activation in the part of the brain that represents touch. When participants tasted the pleasant sensation of glucose and the pleasant aroma of vanillin, similar but different parts of the orbitofrontal cortex were activated, as were other parts of the brain. 10.4.3. Left–right frontal asymmetry Other evidence implicates the anterior cortex in emotion but in a different way. It has generally been thought that the right hemisphere was the dominant hemisphere for processing emotion. We now know, however, that this is far too crude a characterisation of a complex behaviour and function. While the right hemisphere is superior to the left at recognising and perceiving emotional stimuli – such as distinguishing neutral from emotional faces and distinguishing sentences that vary according to their emotional tone – the left hemisphere plays a more important role in the experience of emotion. This hypothesis has been suggested and tested most prolifically by Richard Davidson and his colleagues at the University of Wisconsin (Tomarken et al., 1990; Wheeler et al., 1993; Davidson and Sutton, 1995). In Davidson’s experiments, participants were exposed to film clips designed to elicit specific emotions – positive and negative – as EEG activity was recorded. Participants indicated when they were experiencing these positive and negative emotions during viewing. Participants with greater left-sided activation were more likely to select the pleasant word pairs as being the two that went best together. The results, the authors suggest, show an attentional bias towards positive stimuli in healthy individuals who show frontal left-sided baseline EEG. In a variation of these experiments, Ekman et al. (1990) investigated whether the type of EEG activity associated with a genuine smile (the so-called Duchenne smile) would differ from that generated by false smiles. The Duchenne smile is known as the genuine smile because it spontaneously activates the zygomatic muscles around the corners of the mouth and the orbicularis oculi muscles around the corners of the eyes. SUMMARY 1. Motivation is a general term for a group of phenomena that affects the nature, strength and persistence of an individual’s behaviour. 2. It includes a tendency to perform behaviours that bring an individual into contact with an appetitive stimulus or that move it away from an aversive one. 3. Regulatory systems include four features: a system variable (the variable that is regulated), a set point (the optimum value of the system variable), a detector to measure the system variable and a correctional mechanism to change it. 4. Psychologists believed that aversive drives were produced by deprivation and that reinforcement was a result of drive reduction. 139 CU IDOL SELF LEARNING MATERIAL (SLM)

5. However, the fact that we cannot directly measure an individual’s drive level makes it impossible to test this hypothesis. 6. Many reinforcers increase drive rather than reduce it. Thus, most psychologists doubt the validity of the drive reduction hypothesis of reinforcement. 7. The discovery that electrical stimulation of parts of the brain could reinforce behaviour led to the study of the role of brain mechanisms involved in reinforcement. 8. Apparently, all reinforcing stimuli (including addictive drugs) cause the release of dopamine in the brain. 9. Emotion refers to behaviors, physiological responses and feelings evoked by appetitive or aversive stimuli, although psychologists have defined emotion in various ways. 10. Darwin believed that expression of emotion by facial gestures was innate and that muscular movements were inherited behavioral patterns. 11. A great deal of physiological changes happens when we experience emotion. 12. When we are excited, afraid or angry we note that the increase in heart rate, throbbing temples, increased perspiration, and trembling in your limbs when you are angry or excited about something. 13. The experience of emotions is a result of a series of neurophysiological activations in which thalamus, hypothalamus, limbic system, and the cerebral cortex are involved significantly. 14. One of the earliest physiological theories of emotion was given by James (1884) andsupported by Lange, hence, it has been named the James-Lange theory of emotion. 15. The theory suggests that environmental stimuli elicit physiological responses fromviscera (the internal organs like heart and lungs), which in turn, are associated with muscle movement. 16. Another theory was proposed by Cannon (1927) and Bard (1934). 17. The Cannon-Bard theory claims that the entire process of emotion is mediated by thalamus which after perception of the emotion-provoking stimulus, conveys this information simultaneously to the cerebral cortex and to the skeletal muscles and sympathetic nervous system. KEY WORDS/ ABBREVIATIONS • emotion. -a complex reaction pattern, involving experiential, behavioural, and physiological elements, by which an individual attempts to deal with a personally significant matter or event. • Motivation- the impetus that gives purpose or direction to behavior and operates in humans at a conscious or unconscious level (see unconscious motivation). LEARNING ACTIVITY 1. Emotions are one of the factors that have an impact on motivation. Talk to 4 to 5 of your friends with their experiences with attempting a competitive exam and what motivated them to apply? 140 CU IDOL SELF LEARNING MATERIAL (SLM)

2. Explain the role of brain emotion. UNIT END QUESTIONS (MCQS AND DESCRIPTIVE) A. Descriptive Questions 1. Our parents often complain that the youth is not motivated enough. Is this the same as we talk about motivation in psychology? Explain what psychology talks about motivation. 2. Illustrate the different types of motives of needs that are described in psychology. 3. Can our brain determine our levels of motivation elaborate? 4. We experience and express a range of emotions. However, the emotions we experience are in layers. Explain what are the core or basic emotions that we experience? 5. We say that emotion has to do with heart. According to psychology, emotions are the function of brain. Elaborate the physiological view of emotions. B. Multiple Choice Questions 1. Which of the following is final destination for much of the brain’s information about emotion before action is taken? [a] Amygdala [b] Anterior cingulate cortex [c] Pre-frontal cortex [d] Hypothalamus 2. The James- Lange Theory and the cognitive theory of emotion disagree on whether [a] Specific brain areas are involved in specific emotions [b] Bodily feedback determines which emotion is felt [c] Individuals can judge their emotions accurately [d]There is no biology involved in human emotions 141 CU IDOL SELF LEARNING MATERIAL (SLM)

3. increasing the likelihood of previous behaviour being repeated. [a] Motivation [b]Trigger [c] Emotion [d] Reinforcement 4. The word _ comes from Latin and means ‘to move’ or ‘to stir up’. [a] Motivation [b] Trigger [c] Emotion [d] Reinforcement 5. hemisphere is dominant in experiencing emotion [a] Both [b] Right [c] Left [d] Posterior Answer 1 [c]2 [b]3 [d]4 [c]5 [b] REFERENCES • Martin, N. (2010). Psychology, (4th ed). Pearson Education Limited • Mangal, S.K. (1995). An Introduction to Psychology. Sterling Publishers Private Limited • Eynenck, M. (2014). Fundamentals of Psychology. Taylor & Francis. • Woodworth, R. S. & Marquis, D. G. (2015). Psychology a study ofmental life. Taylor & Francis. • Bernstein D. (2018) Essentials of Psychology. Cengage Learning. • Feldman, R. S. (2012) Understanding Psychology (11th ed). McGraw-Hill Education - Europe • Pinel, J.P.J. (2007). Biopsychology. New Delhi: Pearson 142 CU IDOL SELF LEARNING MATERIAL (SLM)

• Rosenzweig, M. R., Leiman, A. L. & Breedlove, S. M. (1996). Biological Psychology. Sunderland, Mass: Sinauer Associates. • Green, S. (1995). Principles of biopsychology. UK: Lawrence Erlbaum Associates Ltd. • Pinel, J. P. J. (2004). Biopsychology. Boston, MA: Allyn & Bacon. • Annett, M. (1984). Left, right, hand and brain: The right shift theory. London: Lawrence Erlbaum Associates Ltd. • Bannett, T.L. (1977). Brain and Behaviour. California: Brooks/ Cole. • Leukel, F. (1985). Introduction to Physiological Psychology. New Delhi: CBS Publishers 143 CU IDOL SELF LEARNING MATERIAL (SLM)

UNIT 11 HUNGER THIRST Structure Learning Objectives Introduction The Physiological Basis of Hunger The Psychology of Hunger Metabolism and Body Weight Obesity Eating Disorders The Physiological Basisof Thirst Summary Key Words/ Abbreviations Learning Activity Unit End Questions (MCQs and Descriptive) References LEARNING OBJECTIVES After this unit, you will be able to; • Identify the biological factors behind the experience of hunger • Identify the biological factorsbehind the experience of thirst • Explain the factors impacting the experience of hunger and thirst • Describe the different eating habits and their impact on our body. INTRODUCTION Hunger is the set of internal experiences that lead a human or animal to seek food. Appetite describes the preferences that surround the selection of food that is found. For many people, hunger is a set of feelings often focused on the stomach. It may be associated with contractions of the stomach or intestine, and described as \"emptiness.\" Indeed, many of the early ideas about hunger and its opposite, satiety, were described in terms of stomach contractions or stomach distension. Increased physiological understanding has yielded the information that the stomach and intestine are only one part of the system experienced as hunger. Thirst is a conscious sensation that results in a desire to drink. Although all normal humans experience thirst, science can offer no precise definition of this phenomenon because it involves numerous physiological responses to a change in internal fluid status, complex patterns of central nervous system function, and psychological motivation. Three factors are typically recognized as components of thirst: a body water deficit, brain integration of central and peripheral nerve messages relating to the need for water, and an urge to drink. In laboratory experiments, thirst is measured empirically with subjective perceptual scales (for 144 CU IDOL SELF LEARNING MATERIAL (SLM)

example, ranging from \"not thirsty at all\" to \"very, very thirsty\") and drinking behaviour is quantified by observing the timing and volume of fluid consumed. THE PHYSIOLOGY OF HUNGER We usually first become aware of the fact that we are hungry when we feel \"hunger pangs,\" which are just our stomach contractions. For many people, this is a strong incentive to eat, but it is not, physiologically, the most significant indication of hunger. More important is the level of glucose (blood sugar) in the blood. Most of the food you eat gets converted to glucose, much of which is converted by the liver into fat for later use. When the levels of glucose are low, the liver sends signals to the hypothalamus – specifically, the lateral hypothalamus – that levels are low. The hypothalamus in turn triggers whatever habits you have accumulated relating to food seeking and consumption. Another portion of the hypothalamus (the paraventricular hypothalamus) actually tells you more specifically what foods you need, and seems to be responsible for many of our \"cravings.\" The feeling that it is time to stop eating is called satiety. Again, the first indicators may be the distension of the stomach and the intestines – that full or even bloated feeling we all know from thanksgiving dinner. There are also certain hormones that are released when food begins to move from the stomach to the intestines that signal the hypothalamus (this time, the ventromedial hypothalamus) that it's time to stop eating. There is also a hormone released by the fat cells themselves called leptin that decreases appetite via the hypothalamus. I'm sure you've all talked about one person having a better metabolism than another. Some people just seem to burn calories as quick as they eat them, while others gain weight just by looking at food. This is called the set point hypothesis. It suggests that everyone has a certain metabolic set point, a certain weight that your body is geared towards, which is determined by your metabolism, or the rate at which you burn calories. Different people have different set points, and it is believed that these set points can change depending on a number of factors, including eating patterns and exercise. 145 CU IDOL SELF LEARNING MATERIAL (SLM)

Figure 11.1.: Hunger and eating are regulated by a complex interplay of hunger and satiety signals that are integrated in the brain. The connections between what happens in the body and how the brain recognizes it have advanced by leaps and bounds since the 1970s. One of the first discoveries was that many of the same messages or signals that are found in the stomach and intestine are also found in the brain. These so-called gut-brain messages can serve to stimulate or inhibit feeding. As a general rule, the ones produced and released in the body tend to inhibit feeding. Thus cholecystokinin, a hormone that causes the gallbladder to contract, also inhibits food intake. This peptide works both in the body and when put into the brain. Another gut-brain hormone is ghrelin. In contrast to cholecystokinin, ghrelin stimulates food intake whether injected into the body or into the brain. The fat cells are another source of important signals for hunger. The most important of these sources is a hormone called leptin. When this hormone is absent in either humans or animals, massive obesity results. When this hormone is given back, hunger immediately subsides, indicating the important role that this hormone plays in the control of hunger. The amount of leptin released from fat cells increases as the total body fat increases. It thus serves as a circulating marker for the level of fatness. Once in the circulation, leptin acts on the brain. Through a lock-and key mechanism, leptin changes the formation of four other hormones in the brain that regulate eating. 146 CU IDOL SELF LEARNING MATERIAL (SLM)

Figure 11.2.: Overview of food metabolism. When leptin is high, the release of two peptides (neuropeptide Y and agouti-related peptide) in the brain is reduced and two other hormones (cocaine-amphetamine regulated transcript and proopiomelanocortin) are released. Acting in concert, this combination of hormones reduces feeding and relieves the sensations of hunger. Conversely, when leptin is low, the opposite situation occurs, and hunger develops along with the search for food. Insulin is a second major hormone in the body that signals hunger. In diabetic patients who take insulin and tightly control their blood sugars, mild degrees of obesity frequently develop. Similarly, some of the drugs for treating obesity (sulfonylureas and peroxisome proferator- activated receptor-γ agonists) produce weight gains. One likely way this happens is through reducing blood glucose that in turn signals the need for food. The role of circulating glucose in the initiation of hunger has been advanced considerably. Beginning with studies in animals, it was found that a small drop of about 10 percent in glucose preceded the onset of many but not all meals. When this drop in glucose was prevented, the animal did not eat at the expected time. That is, hunger had been prevented by manipulating glucose. The glucose-stimulated hunger can be provoked by giving a drug that mimics the key nerve (vagus) that supplies the pancreas to release insulin. Studies in human beings also found that a small drop in glucose preceded many meals. It has been long known that there were lock-and-key systems in the brain responding to glucose or its deficiency. The 147 CU IDOL SELF LEARNING MATERIAL (SLM)

experiments described above suggest that the brain signals a small release of insulin that leads to a transient decrease in glucose, which in the \"primed\" animal produces an internal feeling of hunger. These many signals for feeding can increase the intake of all available foods, or they can signal intake of certain foods. We know that when we have eaten our fill of turkey at Thanksgiving, there is still room for pumpkin pie or ice cream. The loss of hunger for one food after it is eaten is known as sensory specific satiety, that is, the overall drive to eat can be regulated in parts. This is consistent with the finding that some of the signals described earlier stimulate one type of food intake or another, but not necessarily all. Thus, some signals are known that will specifically reduce the intake of fat and others, carbohydrate. THE PSYCHOLOGICAL BASIS OF HUNGER Hunger is not, of course, entirely a physical process. For one thing, the cultural and even individually learned preferences and eating habits can make a difference. For example, some of us eat regular meals and rarely snack, while others just nibble throughout the day. Every culture has its collection of foods that are preferred and those that are avoided. Many people like the burned flesh of large herbivores (i.e. a steak); others prefer raw squid; others still prefer to graze on a variety of vegetation.... Our culture and upbringing also provide us with various beliefs and attitudes about food and eating in general, and our personal memories can influence our eating behaviours as well. Some of us grow up with the idea that we should never waste food, for example, and many of us have particular attachments to what are sometimes called \"comfort foods.\" Eating is a social thing in human beings and can give one a sense of love and belonging. It has been suggested that for some people, food is a \"substitute\" for the love they crave. Also, some foods – chocolate and ice cream come to mind – seem to reduce anxiety and stress for many of us. One of the strongest learning experiences both humans and animals have is called taste aversion: If we get sick soon after eating something, we can develop an instant dislike for that food for the rest of our lives! Children often say they are \"allergic\" to one food or another when this happens. METABOLISM AND BODY WEIGHT Our body weight is affected by a number of factors, including gene-environment interactions, and the number of calories we consume versus the number of calories we burn in daily activity. If our caloric intake exceeds our caloric use, our bodies store excess energy in the form of fat. If we consume fewer calories than we burn off, then stored fat will be converted to energy. Our energy expenditure is obviously affected by our levels of activity, but our body’s metabolic rate also comes into play. A person’s metabolic rate is the amount of energy that is expended in a given period of time, and there is tremendous individual variability in 148 CU IDOL SELF LEARNING MATERIAL (SLM)

our metabolic rates. People with high rates of metabolism are able to burn off calories more easily than those with lower rates of metabolism. We all experience fluctuations in our weight from time to time, but generally, most people’s weights fluctuate within a narrow margin, in the absence of extreme changes in diet and/or physical activity. This observation led some to propose a set-point theory of body weight regulation. The set-point theory asserts that each individual has an ideal body weight, or set point, which is resistant to change. This set-point is genetically predetermined and efforts to move our weight significantly from the set-point are resisted by compensatory changes in energy intake and/or expenditure (Speakman et al., 2011). Some of the predictions generated from this particular theory have not received empirical support. For example, there are no changes in metabolic rate between individuals who had recently lost significant amounts of weight and a control group (Weinsier et al., 2000). In addition, the set-point theory fails to account for the influence of social and environmental factors in the regulation of body weight (Martin-Gronert & Ozanne, 2013; Speakman et al., 2011). Despite these limitations, set-point theory is still often used as a simple, intuitive explanation of how body weight is regulated. OBESITY When someone weighs more than what is generally accepted as healthy for a given height, they are considered overweight or obese. According to the Centres for Disease Control and Prevention (CDC), an adult with a body mass index (BMI) between 25 and 29.9 is considered overweight ([link]). An adult with a BMI of 30 or higher is considered obese (Centres for Disease Control and Prevention [CDC], 2012). People who are so overweight that they are at risk for death are classified as morbidly obese. Morbid obesity is defined as having a BMI over 40. Note that although BMI has been used as a healthy weight indicator by the World Health Organization (WHO), the CDC, and other groups, its value as an assessment tool has been questioned. The BMI is most useful for studying populations, which is the work of these organizations. It is less useful in assessing an individual since height and weight measurements fail to account for important factors like fitness level. An athlete, for example, may have a high BMI because the tool doesn’t distinguish between the body’s percentage of fat and muscle in a person’s weight. 149 CU IDOL SELF LEARNING MATERIAL (SLM)