Full Notes on the Mind Body and Brain

Unit 3: The conscious self

AOS 1: Mind, brain and body

AREA OF STUDY 1

Mind, brain and body
Consciousness
 Consciousness refers to our level of awareness of our internal world, that is, our own personal thoughts, feelings and perceptions, external world, that is, our surroundings during any particular time, as well as our own existence. Psychological construct (or hypothetical construct) refers to hypothetical ideas regarding a phenomenon that is believed to exist however cannot be directly measured or observed. Consciousness is a psychological construct as it is a concept designed to describe a psychological process that is believed to occur, but cannot be measured. » The mind-body problem** A constantly debated topic related to the relationship between the mind and the brain (body). Self-awareness: our ability to reflect, think and reason about ourselves and the world. Monism: the view that the mind and the body are a single entity (only believe in matter). Materialistic monism: the view that the mind and body are a single entity and that consciousness is a result of complex physical interactions between neurons. » René Descartes (1596-1650) “Cognito, ergo sum” (‘I think, therefore I am’); thinking provides evidence of consciousness and knowledge of our own existence. Consciousness relates to our ability to think, reflect and reason about ourselves and the world. Dualism: the view that the mind, a non-physical entity, and body, the physical flesh, are two separate entities which interact with one another. Descartes believed this interaction occurred in the pineal gland, a small structure in the brain. » William James (1842-1910) Our conscious experience is continuous even though it constantly shifts and changes. Coined the phrase ‘stream of consciousness’, viewing consciousness as a flowing, ever-changing stream of thoughts and feelings. Described our conscious experience as being: o Continuous: our mind is never empty. o Changing: our thoughts are constantly changing from one topic to another. o Personal: everyone’s consciousness is unique. o Selective: we have the ability to choose what to focus on and what to ignore. Like Descartes, James believed that consciousness creates our real experience and, although subjective, should be studied. Has an evolutionary based role as it enhances our ability to adapt to the environment. He was interested in how and why the mind functioned as a whole rather than observing the basic parts (structuralism) as consciousness acts as a whole and thus the separate parts cannot convey meaning; this led to a new approach called ‘functionalism’.

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Unit 3: The conscious self

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States of Consciousness
State of consciousness: refers to the level of awareness of internal and external events. Normal waking consciousness: the state of consciousness in which we are awake and aware of our internal and external events, experiencing a real sense of time and place. It forms a basic standard that allows judgement of all other states of consciousness. Altered state of consciousness: any state of consciousness that is different from normal waking consciousness in relation to one’s level of awareness, perceptions, memories, thinking, emotions, behaviours and sense of time, place, and self-control. It can be induced deliberately (drugs, sleep, meditation) or naturally (fever). Awareness: refers to an individual’s level of consciousness of their internal and/or external events. Attention: relates to the information that is being actively processing, either consciously or outside conscious awareness. Automatic processes: activities that require little awareness and mental effort, and do not interfere with other activities enabling us to complete two tasks at once (divided attention). Controlled processes: activities that require alert awareness and mental effort. Because these processes require our full attention (selective attention), more than one controlled processes cannot be completed simultaneously, otherwise it will only cause interference between the two. Divided attention: the ability to divide our attention and carry out two or more activities at once. Selective attention: selectively attending to certain stimuli while ignoring other stimuli. Perception: process of organising sensory input (internal and external) and interpreting it. Cognition: relates to mental activities such as thinking, problem-solving, reasoning, language

NWC vs. ASC
Level of awareness (awareness of internal and external events) Content limitations (the amount of control we have to limit what we attend to) Controlled & automatic processes (ability to effectively perform two or more tasks at once depending on the level of complexity) Time orientation (ability to correctly perceive the speech at which time passes)

Normal Waking Consciousness Many levels of awareness can be experienced; however we are generally alert to some extent. Content can be limited through our ability to be selective with our attention (controlled). Can complete both controlled and automatic processes.  Controlled: often serial  Automatic: often parallel (divided attention). We have a clear sense of time in which time is perceived as objectively correct.

Altered State of Consciousness Less aware of sensations and external environment (e.g. fever, game of golf). Usually less constrained, controlled and logical. Ability to be selective or divide out attention may be impaired. Carrying out controlled processes is difficult. Ability to perform automatic processes can be decreased.

Sense of time is distorted; time may appear faster or slower than in reality.

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Unit 3: The conscious self

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Perceptual & cognitive distortions (the degree of awareness and efficiency of our perceptions and cognitions)

Perception is realistic and clear:  Able to make sense of sensory input  Have real awareness of internal external events  Pain is perceived realistically Thoughts are organised and logical:  Capable of mental processes Generally aware of and are able to control our feelings (e.g. hiding our true feelings), and show a normal range of appropriate emotions.

Distortions may occur:  Ability to interpret sensory input is impaired (e.g. less pain, colours more vivid)  Cognitive functioning is impaired (thoughts, problem-solving, memory)  May lose touch with reality Usually less control of emotions. They can become more intense (dreams), can be dulled (state of shock), and might also be inappropriate. Ability to maintain self-control is usually reduced, though sometimes increases (decrease in inhibitions causing us to do things we usually wouldn’t).

Emotional awareness (the experience of emotions)

Self-control (the ability to monitor one’s behaviour)

Able to maintain self-control:  Able to direct our thinking  Can monitor what we say and do

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» ASC: Daydreaming Daydreams: shifting of our attention from external stimuli to internal thoughts. Naturally occurs (especially when stationary) and we spend about a third of our life daydreaming Tends to occur in 90-minute cycles Serves many purposes; they allow us to imagine our fantasies, overcome boredom, enhance creativity, plan ahead for future actions, conversations or social situations, and they help us with reasoning, decision making and problem solving. » ASC: Meditative Meditation: the act of achieving an ASC of deep relaxation by using mental exercises to heighten one’s awareness of a single stimulus (e.g. breathing, symbol, word/sound, nothing) to the exclusion of others. Physiological changes include: reduction in heart rate, respiration, and blood pressure; increase in alpha and theta waves. » ASC: Alcohol-induced Psychoactive drugs: chemical substances that affect the nervous system and brain activity; they impact on the consciousness by altering thoughts, feelings, perceptions and behaviours. They are the most common method of purposely altering one’s state of consciousness (such drugs include depressants, stimulants, opiates, hallucinogens, marijuana). Alcohol: a psychoactive drug of tolerance. It is a depressant that slows down nervous system activity and causes an ASC, ultimately reducing inhibitions. Low doses of alcohol can result in a person being more stimulated, active and talkative; high doses of alcohol can cause blackouts, comas and death.

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Unit 3: The conscious self

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Daydreaming Level of awareness Decreases (particularly awareness of external stimuli). Less limitations due to less control (thus, selective attention is difficult). Controlled processes are difficult, including the ability to divide out attention. Cognitive processes are impaired and perceptions are distorted (e.g. less awareness of pain).

Meditation Unaware of internal and external events (except for single stimulus). Thoughts usually strictly limited; attention is narrowly focused on single stimulus. Controlled processes are difficult; exercises carried out during meditation are initially controlled processes (∴ requires selective attention). Cognitive processes are under control and perceptions are distorted (e.g. less awareness of pain).

Alcohol-induced Decreases; both internal and external events due to n. system slowing down (shortened attention span). Less limitations (content may be broader).

Content limitations

Controlled & automatic processes

Functioning of brain is impaired, thus both processes are difficult (also affects reaction times). Cognitive processes are impaired (reflexes, reaction time, slurred speech). Perceptions are distorted (sensory stimuli). Emotional control is impaired (false sense of confidence affects behaviour and expression of emotions). Decreases; monitoring behaviour is unlikely (inhibitions reduced). Distorted; time may appear to move very fast or slow.

Perceptual & cognitive distortions

Emotional awareness

Emotions may be enhanced (positive daydreams) or Able to control emotions, depressed (negative). whilst reducing feelings Response to emotional associated with stress. situations may be lowered. Decreases; monitoring behaviour is unlikely (e.g. dribbling). Distorted; time may appear to move very fast or slow. Increases; however requires practice. Distorted; time may appear to move very fast or slow.

Self-control Time orientation

Altered State of Consciousness: Sleep
   Sleep is an ASC whereby an individual temporarily loses normal waking consciousness, including some awareness of yourself and your environment. Circadian rhythm: biological rhythms that occur approximately once every 24 hours, for example the sleep/wake pattern and body temperature. Ultradian rhythms: a biological rhythm that is shorter than 24 hours or occurs more than once a day, for example REM/NREM cycles. » Characteristics of sleep as an ASC Level of awareness: We are not completely unconscious (e.g. those in coma show different brainwaves) nor are we completely conscious. However we are aware of our external environment to some extent (e.g. loud stimuli may cause us wake up, incorporate what is happening around us into our dreams and know the location of the edge of the bed to avoid failing of).

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Content limitations: We lose conscious control of our thoughts causing us to dream about events that tend to be peculiar. Therefore, the contents of our dreams are much broader and deeper. Controlled and automatic processes: Being able to perform other tasks whilst asleep is almost impossible, with the exception of sleepwalkers (somnambulists) who usually carry out automatic processes including everyday routine (toilet, making a sandwich, etc.) when they sleepwalk. Perceptual and cognitive distortions: Attention to sensory stimuli (vision, auditory, smell, taste, touch, balance) and perception of pain decreases. Thoughts are more likely to be disorganised and unrealistic when dreaming, and once awake, we remember very little about our dreams. Emotional awareness: Emotions can be more or less intense during sleep (a nightmare can make us feel scared; a good dream can uplift our mood). Self-control: Ability to maintain self-control is lowered causing some individuals to snore, dribble, grind their teeth or sleep-talk. Time orientation: Ability to perceive how fast time passes is affected; time may feel fast or slow.

Non-Rapid Eye Movement (NREM) sleep
Stage 1 NREM sleep  Lasts around 5 minutes on average (though it can range from 30 seconds to 10 minutes). It is a stage of very light sleep from which we can easily be awakened. If awakened, we often feel as if we were not asleep at all.  We enter a relaxed state known as a hypnogogic state whereby we transition from being awake to being asleep. During this state, we may experience hallucinatory images or hypnogogic (hypnic) jerks (involuntary muscle twitches that cause us to jolt).  Alpha waves replaced by theta waves.  Our eyes roll slowly, our muscles relax, and heart and breathing rate decreases. Stage 2 NREM sleep  A stage that takes up about 50% of our sleep and is considered as the point at which true sleep begins. During our first NREM/REM sleep cycle, we spend about 20 minutes in stage 2.  Fairly easy to be woken up. If we are woken, it is likely that we still won’t believe we were asleep.  Characterised by the appearance of sleep spindles and K-complexes among the theta waves.  K-complexes occur about once a minute. Sometime occurs after a sleep spindles episode, but can also be triggered by environmental stimuli (door closing or someone calling your name).  Our eyes stop rolling, our muscles become further relaxed and breathing and heart rate continues to decrease. Stage 3 NREM sleep  A brief transitional stage that marks the beginning of deep sleep (or slow wave sleep).  Less responsive to external stimuli and more difficult to awaken.  If awoken during this stage, we feel very groggy and disorientated.  Brainwave patterns consist of slower and larger delta waves 20-50% of the time and some theta waves.  Our eyes do not move, our muscles are relaxed and heart and breathing rates continue to become slower and more regular.

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Stage 4 NREM sleep  A stage in which we are in the deepest sleep; it is extremely difficult to wake someone who is in this sleep stage as level of conscious awareness is very low.  Can still be sensitive to certain stimuli, such as a baby crying or a smoke alarm.  We spend about 30 minutes in stage 4 sleep during the first NREM/REM sleep cycle and it has probably been an hour since we first fell asleep.  Brainwave patterns consist of regular, slow and large delta waves for more than 50% of the time.  No eye movement, muscles are very relaxed, and heart and breathing rates are at their slowest and most regular during sleep.  Body temperature drops slightly, being the lowest in stage 4 sleep.  Often grouped together with stage 3 because their main distinguishing feature is the percentage of delta waves. Collectively, sleep stages 3 and 4 of NREM are called slow wave sleep.  Sleepwalking, night terrors and bedwetting are most likely to occur during slow wave sleep.

Rapid Eye Movement (REM) sleep
    A period of sleep when our eyes move rapidly for short bursts of time. The first cycle of REM sleep lasts for about 10 minutes, and is a lighter sleep compared to stages 3 and 4 of NREM sleep, and thus it is easier to wake up. If awoken during REM sleep, unlike NREM sleep, we are likely to recall our dreams. Often, REM sleep is referred to as paradoxical sleep because although the body can appear calm on the outside (virtually no muscle activity), other bodily systems and the brain are highly active, reflecting many of the features that appear when we are awake. » Nightmares** Unlike night terrors, nightmares occur in REM sleep and are more likely to be remembered. Although they are more frequent in childhood, they can be experienced by adults (W > M). » Brainwaves Our brain is very active during REM sleep, and thus the EEG patterns resemble those of a person who is awake and alert. Compared to stages 3 and 4 sleep, brainwaves are irregular (desynchronised), faster (high frequency) and smaller (low amplitude); beta-like waves. Sawtooth waves (a special type of theta-like wave that resembles the blade of a saw) may be found among these random and fast beta-like waves, especially when there is a burst of rapid eye movement. » Physiological changes Amount of electrical activity in the muscles that allow the eyes to move increases due to the repetitive bursts of rapid eye movement. Heart rate, blood pressure, and respiration (irregular breathing) increase and fluctuate. Body temperature tends to change in accordance to the surrounding environment. No muscle tension; the muscles that move voluntarily (particularly those below the neck) are very relaxed to the point of being almost paralysed (besides the occasional twitching). This paralysis is known as muscle atonia or cataplexy (total relaxation of muscles to the point of paralysis during REM sleep). 6|Page

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Unit 3: The conscious self

AOS 1: Mind, brain and body

NREM/REM Sleep Cycle
          NREM/REM cycle can be plotted onto a graph known as a hypnogram (refer to diagram below). On average, we go through one cycle of NREM/REM every 90 minutes. Adults typically experience 4-6 NREM/REM cycles per night. NREM takes up about 80 per cent of our total sleep time. 1st cycle: N1 → N2 → N3 → N4 → N3 → N2 → REM 2nd cycle: N2 → N3 → N4 → N3 → N2 → REM 3rd cycle: N2 (1 hour) → REM (during this cycle, we spend longer time in REM sleep). The 4th, 5th, and sometimes 6th cycles are similar where we are unlikely to enter stages 3 and 4 sleep and increasingly spend more time in REM sleep. We tend to wake up (usually without conscious awareness) before (directly from stage 2) or after REM sleep, and in the fifth sleep cycle, but often go back to sleep and begin a new cycle. The exact pattern of sleep varies among all individuals, however two similar features that all people share: 1. Stages 3 and 4 sleep typically occur in the first two cycles of NREM/REM sleep cycle 2. We spend more time in REM sleep as the night progresses

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The period between being asleep and waking up, a time when brainwaves are predominantly alpha waves, is called the hypnopompic state. Similar to the hypnogogic state, we may experience vivid visual images during this phase, known as hypnopompic images. Sleep patterns change with age: o Newborns sleep for about 16 hours with about 50% of the time in REM sleep. o Children sleep for about 9-10 hours and adolescents o Adults sleep for about 8 hours with about 25% in REM sleep. o 60 years+ very little time is spent in stage 4 with sleep lasting for about 6 hours (still with 20-25% in REM sleep).

Purpose of Sleep
» Survival theories of sleep Sleep serves as a purpose of increasing an organism’s chances of survival within its environment. There are different reasons regarding why sleep is required for different species (hunt food, hide and conserve energy): i. Sleep depends on the need to find food.  Animals that need to find more food to survive sleep less. ii. Sleep depends on an animal’s vulnerability to predators.  Small animals that are very vulnerable to predators sleep more as a way of hiding safely.  Being more exposed, larger animals will sleep less in order to be ready to escape from predators. iii. Sleep conserves energy.  During sleep, metabolism slows down which reduces the need for food. Conserving energy through the means of sleeping is important for hibernating animals that sleep during winter, a time in which there is a lack of supply in food and the weather conditions are harsh. Criticisms  Does not explain why we must have sleep, but rather that sleep is very useful. Regardless of the amount of food or danger, all species must sleep because not getting enough can lead to serious consequences.  

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Sleeping can be dangerous for animals that are highly preyed upon. Animals that are asleep become very vulnerable as they are unlikely to be able to respond to danger due to the loss of awareness during sleep.

» Restorative theories of sleep  Sleep recharges our bodies, recovering from the physical and psychological work during the day and ultimately allows our body’s growth processes to occur.  According to the restoration theory: i. Sleep repairs and replenishes the body and prepares it for action the following day, in order words, it looks after the health of the physical body. Activities that are more physically demanding should increase sleep. ii. Sleep enhances mood. Many of our hormones and neurotransmitters have an impact on our mood and emotions, and during sleep a number of these are activated. Thus, a lack of sleep may lead to negative thoughts, feelings and behaviours. iii. Sleep activates growth hormone. Growth hormone has been linked with sleep particularly during the early years and adolescence as the more you sleep, the more likely you are going to grow and meet your potential growth. iv. Sleep increases immunity to disease as it is a natural medicine that helps our immune system become stronger through the way in which immune cells are produced during sleep. Going without sleep leads to our immune system to respond unnaturally, making us more prone to disease and infection. v. Sleep increases alertness as it keeps our minds alert and assists our psychological state. Not getting enough sleep can lead to the tendency of being inattentive and more easily distracted. vi. Sleep consolidates memories (a process where new memories are transferred into long-term memory) as it plays an important role in forming new memories (according to the consolidation theory of memory). Information that you have taken in during the day is more likely to be remembered after a good night’s sleep. Criticisms  Restorative theories suggest that more sleep is required to recover ourselves from physical activity. Other than partaking in extreme physical activities (such as a 100km marathon) there is little evidence to support that we need more sleep when we exercise.  If the above is true, it can also be assumed that those who do little exercise would sleep less, however, there is no evidence to support this as bed-ridden people show sleep patterns similar to people who are normally active individuals.  The theory assumes that our body rests during sleep. However during sleep, the brain is still active. Blood flow increases and energy expenditure occurs during REM sleep, slowing down the synthesis of proteins and ultimately assisting the body in getting ready for the following day.

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Unit 3: The conscious self

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Studying States of Consciousness
    Sleep is a dynamic process. Like normal waking consciousness, we experience a number of different states (known as stages) during our sleeping time. Physiological changes that occur throughout sleep are the most objective and reliable means of indicating different states of consciousness. Ideally, studying consciousness should not be conducted through the use of only one method. In order to collect rich data, sleep laboratories are used along with a wide range of other methods.

Physiological Measures
    » EEG (electroencephalograph) DARE activity in the brain in the form of brainwaves by monitoring the electrical activity of the brain which is detectable on the outside of the skull (tiny electrodes are placed on scalp). The recordings produced from an electroencephalograph are known as electroencephalograms. BRAINWAVES Brainwaves occur in frequency (the number of brainwaves per second) and amplitude (the height of the peaks and troughs of the curved graph). Other brainwave patterns (usually not long-lasting) can occur during these patterns such as Kcomplexes (a sharp rise and fall in amplitude) and sleep spindles (periodic bursts of rapid or high frequency). Both indicate stage 2 NREM sleep; sleep spindles can be found in stage 3 and 4 NREM sleep, although rarely. Sawtooth waves are random, fast waves that are slightly bigger than alpha waves. Although they resemble waves for being awake, they occur among the waves during REM sleep and associated with dreaming.

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» EOG (electrooculargraph) DARE activity of the muscles that allow the eye to move. Electrodes are attached to the area around the eyes. Indicates whether an individual is in one of the two phases of sleep: o No or very little rapid eye movement → NREM sleep. o Bursts of rapid eye movement → REM sleep. The recordings produced from an electroencephalograph are known as electrooculargram. » EMG (electromyograph)** DARE activity of muscles. Electrodes are attached to the skin directly above the muscles (usually the ones under the chin). Indicates whether an individual is awake or asleep, and if asleep, REM or NREM sleep. The recordings produced from an electromyography are known as electromyogram. 11 | P a g e

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Unit 3: The conscious self » Polysomnogram A continuous moving chart that displays data collected simultaneously from an EEG, EOG, EMG, and any other devices. Allows researchers to compare a multiple number of recorded data simultaneously, and thus make more informed decisions about the state of consciousness and any underlying problems.

AOS 1: Mind, brain and body

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Other Measurements
                 » Heart rate Measured using a standard heart rate monitor or electrocardiograph (ECG/EKG): DARE activity of the heart muscles (in bpm). When awake, heart rate may differ considerably depending on the activity the individual is engaged in (e.g. exercise will cause it rise whilst drowsiness will cause it decrease). ASC → varies; (increases with stimulant drugs such as caffeine and decreases with meditation). NREM → usually slow and regular, often slower than resting heart rate. REM → varies; may rise to the level of heart rate seen when carrying out strenuous exercise. » Body temperature Varies in a regular way over a 24 hour period, following a circadian rhythm. Body temperature tends to peak in the mid-afternoon and drop to its lowest point in the early hours of the morning. It is linked to alertness, and fluctuation (irregular rises and falls) in temperature can lead to drowsiness. Body temperature is predictable, and despite changes in alertness, there is little variation in daily rhythm when awake. ASC → May drop (alcohol-induced state; hypothermia) or rise (ecstasy; hyperthermia or dehydration) NREM → body temperature reaches its lowest levels. REM → unregulated; changes depending on the temperature in the surrounding environment. » GSR Galvanic skin response refers to the physiological response that indicates the electrical conductivity of the skin. Conductivity of the skin (rate at which the skin conducts electricity) increases as it becomes more moist as a result of perspiration. Moisture is a good conductor and thus why we experience a larger electrical shock when our hands are wet than when they are dry. NWC → Increase due to events that cause us to perspire (such as strong emotional reactions, physical exercise or being very aroused) or decrease when relaxed and not in a hot environment. ASC → GSR may increase (after taking stimulants) or decrease (through meditation). 12 | P a g e

Unit 3: The conscious self

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Other methods to study states of consciousness
     » The use of sleep laboratories A sleep laboratory is a place used for scientific research on sleep, usually resembling a bedroom. Participants are usually ‘wired up’ to record the physiological measurements and the researcher observes the participant from a different room. The researcher has the ability to control environmental aspects such as room temperature and maintain this for all participants. Throughout the participant’s time in the laboratory, both when they are awake and asleep, data is recorded. Waking participants at particular points and asking them about their experience may also give an indication of the mental processes occurring at the time. E.g. dreams are more likely to be remembered when woken from REM sleep. » Video monitoring Video monitoring is a common method used to sleep in laboratories and in the person’s own home to observe sleep. Uses infrared cameras (or cameras in a room lit with infrared light) that operate silently to allow footage to be seen and taped in the dark without disturbing the sleeping participant. Therefore the angle in which the participant may be observed from is limited. » Self reports Self-reports are statements and answers to questions made by the participants concerning their thoughts and feelings. They can be carried out in various ways such as in the form of questionnaires (with open and/or closed questions), diary entries and interviews.

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Unit 3: The conscious self Research method

AOS 1: Mind, brain and body

Description

Advantages

Limitations » Cannot describe the person’s private and personal conscious experience » Changes in physiological events may be due to other reasons, not a change in state of consciousness » An artificial environment that may disrupt normal sleep patterns » Sleeping participants may be frequently woken up and this may affect normal sleep patterns » Being monitored and wired up can be a frightening or invasive experience, and thus participants may find it hard to fall asleep or even agree to participate in the study » Data can be open to interpretation (thus open to bias) so requires clear definitions for a specific behaviour » May miss important events if only considering still photographs every few seconds/minutes. » Participant’s behaviour may be blocked from view of the camera

Physiological measurements

Recording of physiological (physical body) events

» Most objective and reliable means of indicating different states of consciousness

Sleep laboratory

A place used for scientific research on sleep that usually resembles a bedroom

» Research is conducted in a controlled environment » A number of research methods can be employed at once » The equipment is difficult to transport outside the laboratory thus making it convenient » Researchers can work in their workplace with all their resources and not intrude into participants’ homes » Insight into observable behaviour during sleep » Can be undertaken in sleep laboratory or in normal bed (natural setting) » Researchers can continuously monitor the behaviour, either at the time of collection or at a later stage or both » Data can be recorded alongside the physiological measurements at the time

Video monitoring

Using infrared cameras (or cameras in a room lit with infrared light) that operate silently to allow footage to be seen and taped in the dark without disturbing the sleeping participant

Self-reports

Statements and answers to questions made by the participants concerning their thoughts and feelings

» Gives an important insight into actual thoughts and feelings of participants

» A subjective measure that is open to interpretation, thus results may be inaccurate » Results are difficult to collate

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Sleep Deprivation
 Sleep deprivation: not getting the amount of sleep we need in order to function properly; this may be total or partial sleep deprivation. The exact amount of sleep that individuals need vary depending on the following factors: » Age  Refer to the diagram on page 11 (AOS1).  It can be seen that most teenagers need 9-10 hours of sleep per night, whilst a young child needs more and an adult needs less to perform at their best. » Lifestyle  Examples of lifestyle influencing the amount of sleep we need include: day/night shifts, sleeping quiet/noisy places, having an active/inactive lifestyle, having a stressful/simple life, etc. » Genetics  Genes may influence our sleep/wake cycle; this applies particularly to identical twins who tend to have more similar sleep patterns than fraternal twins.  Females also tend to need more sleep than males and thus are more prone to sleep deprivation.

Total Sleep Deprivation
Total sleep deprivation: going without sleep within a 24 hour period whether it be for one night or for several nights; being totally deprived of sleep for an extended period of time may lead to death. Hat phenomenon: a feeling of tightening around the head as though a hat that is too small is being worn; we suffer from this as a result of being totally sleep deprived for a few days. Sleep deprivation psychosis: a state in which one becomes depersonalised with a loss of sense of personal identity and increased difficulty in coping with other people and the environment.      » Effects of Total Sleep deprivation Difficulties concentrating (particularly simple, repetitive or boring tasks) Microsleeps Mood changes (irritable, grumpy, etc.) Hat phenomenon Delusions and hallucinations  Sleep deprivation psychosis Other:  Short-term memory problems  Disorientated  Finger tremors  Slurred speech

Partial Sleep Deprivation
Partial sleep deprivation: getting some sleep within a 24 hour period but not enough to meet one’s needs. Chronic sleep deprivation: not having enough sleep over an extended period of time; long-term sleep deprivation. o Psychological effects: anxiety disorders, mood disorders, depression, decline in mental health, nocturnal memory consolidation impaired. o Physiological effects: heart disease, obesity, diabetes, some forms of cancer, accelerated ageing process, sleep disorders such as insomnia.

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» Psychological Effects of Short Term Sleep Deprivation Cognitive difficulties  Difficulties in paying attention and  Poor decision making concentration  Memory problems  Difficulty processing information  Impaired creativity  Difficulty thinking and reasoning  Distorted perceptions Affective disturbances  Mood disturbances  Lack of motivation  Previously enjoyed activities seem dull  Feelings of fatigue Behavioural difficulties  Slowed performance  Risk-taking behaviour  Clumsiness, injuries  Problems performing tasks (especially simple and repetitive tasks and ones that require sustained attention; short, complex, difficult tasks are often not affected by sleep deprivation). » Physiological Effects of Short Term Sleep Deprivation  Slower physical reflexes  A heightened sensitivity to pain  Hand tremors  Headaches  Droopy eyelids  Lower energy levels  Difficulty in focusing eyes

Loss of REM and NREM sleep
  The purpose of REM and NREM sleep is not conclusive and still debated. REM and NREM sleep are both important for psychological and physiological well-being (NOT REM sleep → psychological; NREM sleep → physiological). » Loss of REM sleep Lack of REM sleep may lead to memory and learning problems; it is believed that during REM sleep, the high level of brain activity helps transfer newly learnt information into our long-term memory. However, there is a lack of research to show a link between loss of REM and memory problems; brain damaged people and medication that prevents REM sleep do not experience more memory problems than usual. Lack of REM sleep may lead to disruption in mood (such as grumpiness, irritability and sadness). The release of neurotransmitters is interrupted by REM sleep allowing the brain receptors to recover and become more likely to react after a break. These neurotransmitters are likely to affect mood and learning. Lack of REM sleep may lead to less protein synthesis in the brain, meaning that the growth of the nervous system (incl. brain) is affected and the brain may not be able to replenish properly. » Loss of NREM sleep Lack of NREM sleep (mainly stages 3 and 4) may lead to disruptions in growth and restoration of the body. Our brain is less active and our body’s metabolism slows down which could provide an opportunity for brain cells to be repaired and waste products to be replaced. Therefore animals with higher metabolic rates and people involved in strenuous physical activity (e.g. marathon runners) spend more time in stages 3 and 4 NREM sleep. 16 | P a g e

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Sleep Recovery Patterns
   » Amount of sleep required Sleep debt: The total amount of sleep loss from not having an adequate amount of sleep. However one does not need to sleep the same amount of hours of sleep that one has loss in order to make up for all the sleep missed. A good night’s sleep as well as sleeping in is enough to recover from sleep deprivation, though sometimes it may require a few more nights of slightly longer sleep than usual depending on the amount of sleep missed. Most sleep deprivation effects are temporary and recovering without any long-term psychological and physiological problems is likely. Though this may not apply to those suffering from a sleep disorder (e.g. insomnia) or a condition affecting their quality of sleep in which recovering from sleep loss may either improve or worsen the condition. » REM rebound REM rebound: An effect that involves a significant increase in the amount of time spent in REM sleep and occurs as a result of being deprived of REM sleep. An increase in the intensity of REM dreams also occurs. » Microsleeps Microsleep: A brief involuntary period of sleep that occurs in the midst of a wakeful activity (drifting off to sleep and losing concentration on what we are doing). Assists us in overcoming or preventing sleep deprivation. Usually lasts 3-15 seconds and we are often unaware of a microsleep.

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Adolescent sleep/wake cycles
 During teenage years, most people experience: o a delayed onset of sleep whereby people’s sleep/wake pattern shift towards the evening (i.e. go to sleep later). o the need for more sleep (9-10 hours) than an adult and sometimes late childhood in order to function at their best. These experiences or shift in sleep patterns are biological and a normal part of life. By adulthood, the adolescent sleep/wake cycle shifts back to an adult pattern in which most adults need about 8 hours of sleep (females: 19.5 years & males: 21 years). Sleep/wake hormones such as melatonin (which causes sleepiness) and cortisol (which causes alertness) are often delayed for up to two hours. Therefore, this explains why teenagers tend to stay up late and sleep in longer during the mornings.

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Components of the Brain
The structures of the brain are not fragmented whereby although each structure has their own individual responsibility, they interact together in order for our body to function the way it does. » Forebrain  Responsible for thinking processes including problem solving and planning, memory, language, emotions and body movement.  Includes several subsections: the hypothalamus, thalamus and cerebrum.  The outer area of the cerebrum is called the cortex (or cerebral cortex).  The cortex comprises two hemispheres which are connected to each other by the corpus callosum. » Midbrain  Links the hindbrain with the forebrain  Important for sleep, movement and arousal  Includes: reticular activating system (RAS) » Hindbrain  Links the spinal cord with the brain  Important for movement and balance  Includes: brainstem, medulla, pons, cerebellum, parts of the reticular formation

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Nervous System (NS)
Central Nervous System
Brain Spinal Cord

Peripheral Nervous System
Autonomic NS Somatic NS

Sympathetic NS

Parasympathetic NS

Central Nervous System
 Central nervous system (CNS): one part of the body’s overall nervous system and consists of the brain and spinal cord which runs from the brain stem, through the bones of the spine (vertebral column) and to the lower middle section of the spine. CNS enables the brain to communicate with the body by conveying messages from the body to the PNS and vice versa (acts like a postman). Spinal cord is segmented; the upper section is responsible for communication between the brain and the upper parts of the body; the lower section is responsible for lower parts of the body (such as legs, toes and feet).

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Peripheral Nervous System
 Peripheral nervous system (PNS) communicates: o information (internal: aches & external: temperature) from the body’s organs, glands and muscles to the CNS o information from the CNS to the body, via motor neurons The PNS has two subdivisions: the somatic nervous system and the automatic nervous system.

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» Somatic Nervous System  Somatic nervous system: responsible for the voluntary movement of skeletal muscles.  Motor neurons (nerves) communicate messages from the CNS to the particular muscles that an organism intends to move at any particular moment.  The CNS and PNS work together to enable an organism to interact with the environment. Example: When patting a dog, motor neurons carry information from the brain to the muscles in the arm and hand allowing them to move, and the sensory neurons carry information about the feel of the dog from the sensory receptors in the skin to the brain for processing.

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» Autonomic Nervous System Autonomic nervous system: responsible for involuntary body functions, and communication of information between the CNS and the body’s nonskeletal muscles, and internal organs and glands (which carry out basic bodily functions needed for survival such as digestion & heartbeat). Operates without voluntary control (some can be influenced voluntarily such as breathing and blinking), enabling the organism to have the cognitive resources to pay attention to other matters such as responding to threats or other survival needs in the external environment. Fight-or-flight response: the autonomic NS activates causing an increase in arousal. This allows the sympathetic nervous to prepare the body as the brain triggers the release of hormones by the adrenal medulla. Controls the function of internal organs (viscera) through the muscles (in the skin, eye, stomach, intestines, bladder, heart, etc.) and glands (pancreas, adrenal gland, sweat gland).

Sympathetic nervous system - Activates when faced with danger, fear or anxiety. - This is essential for survival as it provides us with an immediate response such as running away, fighting, or freezing; this is known as the fight, flight or freeze response/fight-or-flight response. Parasympathetic nervous system - Activates in moments where fear or danger is absent (counteracts the SNS; brings body back to normal and ensures that it is calm). - Responsible for maintaining the stability of normal bodily functioning (homeostasis) such as digestion, normal heart rate and normal breathing.

Cerebral Cortex: The Four Lobes
Cerebral cortex: thin (3mm) outer layer that covers the cerebral hemispheres and contains billions of neurons. Its many folds, grooves and bulges (convolutions) increase the cortical surface area. Motor cortex: receives, processes and sends information about voluntary bodily movements. Primary cortex: receives and processes information from our different senses. Association areas/cortex: integrates sensory, motor and other information and is involved with more complex mental abilities such as thinking, decision-making and problem solving. It makes up the majority of the cortex, approximately 80%.

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» Frontal Lobe  Largest lobe, forward half of each hemisphere.  Has many functions including voluntary movement, personality, emotions, and cognitive processes such as attention, planning, language, problem solving, thinking, and decision-making. Primary motor cortex  Responsible for controlling voluntary body movements  Functions contralaterally (left primary motor cortex controls movements on right side of body, etc.)  The more complex the movement of a particular body part, the more cortical space devoted (e.g. our fingers require more motor neurons to move compared our thighs which we have less control of, and thus, they have more space on the primary motor cortex). Broca’s area  Responsible for movement of mouth muscles which allow speech production.  Located in the left frontal lobe. Functions  Production of clear, articulate speech  Vital for the proper grammatical structure of sentences  Coordinates the movements of the muscles required for speech  Supplies information to the appropriate motor cortex areas » Parietal Lobe  Located behind the frontal lobe.  Receives and processes sensory information, and sends information to other areas of the brain.  Right parietal lobe is responsible for the perception of three-dimensional shapes and designs. Primary somatosensory cortex  Receives and processes sensory input from the skin and body, allowing us to perceive bodily sensations. 21 | P a g e

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Functions contralaterally (PSC on the left receives and processes sensory input from the right side of body, etc.)  The amount of cortex devoted to a particular body part depends on the sensitivity and amount of use of that body part (e.g. more cortex would be devoted to our fingers and tongue which are very sensitive). » Temporal Lobe  Located in the lower central area of the brain.  Primarily involved in auditory perception as well as memory, enabling us to link emotions with memory, show appropriate emotional responses to sensory information, and to identify and recognise faces and objects.  Damage to temporal lobes can lead to amnesia. Primary auditory cortex  Receives and processes sounds from both ears.  Verbal sounds are processed in the left PAC and non-verbal sounds in the right PAC. Wernicke’s area  Located in the left temporal lobe.  Responsible for the comprehension and interpretation of the sounds of speech.  Damage to this area leads to impairment in the ability to produce meaningful speech. Functions  Enables comprehension of speech/language.  Enables interpretation of the written word.  Locates words from memory to express a particular meaning.  Creates meaningful and/or grammatically correct speech. » Occipital Lobe  Located at the rear area of each cerebral hemisphere.  Responsible for processing visual stimuli.  Damage to the occipital lobe can cause blindness. Primary visual cortex  Major destination of visual information from sensory receptors on retina.  Information from left side of each retina is sent to the left PVS, and vice versa.  Information from centre of the visual field and of each retina is processed in both occipital lobes/PVC.

Hemispheric Specialisation
Both hemispheres of the brain appear to be symmetrical in terms of shape, size, and in most functions. Therefore, both the left and right have specialised functions whereby some neural activities occur in only one particular hemisphere (these functions are lateralised as opposed to contralateralised). However both hemispheres work together in a coordinated way. Left Hemisphere (verbal & analytical functions) Right Hemisphere (non-verbal functions) Controls voluntary movement on the right side Controls voluntary movement on the left side Receives sensory information from the right side Receives sensory information from the left side Verbal functions (reading, writing, speech) Non-verbal tasks Analytical tasks (maths, evaluation) Spatial and visual thinking (jigsaws, map reading) Logical reasoning Creativity (new ideas) 22 | P a g e

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Reticular Activating System
        Reticular activating system (RAS): a network of neurons that extends in many different directions from the reticular formation to different parts of the brain and the spinal cord. Reticular formation: a neural network that is located throughout the brainstem (midbrain, pons, and medulla) and is divided into two parts (ascending and descending reticular formation). During NWC, blood flow in the RAS increases due to higher level of activity by the neurons of the RAS, leading to increased awareness. Blood flow and level of neural activity in the RAS decreases when we become drowsy. Damage to the RAS can disrupt the sleep/wake cycle, and may cause a person to go into a coma. » Main functions of the RAS Responsible for regulating levels of arousal from being highly alert and attentive to being less aroused and attentive (during wakefulness). Responsible for the transition between sleep and wakefulness. Plays a role in selective attention; it highlights neural activity and then bombards the cortical area that is related to the task or stimulus that the individual is attending to with blood flow.

Thalamus
 Thalamus: a brain structure that filters information from our senses (except smell) and directs it to the cerebral cortex. It is shaped like two eggs and is located in the forebrain (in both hemispheres), beneath the cortex and above the brain stem. A damaged thalamus may lead to difficulty in interpreting incoming sensory input and may cause loss of any sense except smell; rapid changes in mood; may be unable to speak or move, etc. Due to its important role in consciousness, damage to the thalamus may cause a person to lose consciousness or lead to coma. » Main functions of the thalamus Allows us to pay attention to sensory stimuli. This process involves the thalamus receiving incoming sensory information and then transmits this information to the relevant cortex for the sensory input to be processed. Allows us to direct our attention or switch particular sensory input on and off, i.e., giving more importance to some information and less to others. The thalamus does this by determining which signals are forwards to the cerebral cortex for processing and which are not. Plays an important role in regulating states of sleep and wakefulness.

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Comparison
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Conscious and Cognitive Processes
Cognition: the knowledge, beliefs, thoughts and ideas we have about ourselves and our environment. Cognitive processes: includes those mental processes involved in acquiring, retaining and using knowledge (a major aspect of cognition involves attention, perception, memory, language and learning).

Aphasia
Aphasia: a language disorder that is apparent in reading, writing and speech, and is caused by brain damage » Broca’s aphasia  Broca’s aphasia: a language disorder that impairs one’s ability to produce fluent speech and thus requiring great effort.  Results from damage to Broca’s area which is located in the left frontal lobe near the motor cortex.  Individuals are aware of their condition.  Has the following characteristics: o Speech is non-fluent and slow. o Speech requires much concentration and effort o Pronunciation of words may be difficult. o Sentences tend to be very short and made up of verbs and nouns. o Words lack grammatical endings (e.g. –ing, -ed) o Writing is difficult. o Spoken and written language can often be understood, however, completed syntax may confuse aphasics. » Wernicke’s aphasia Wernicke’s aphasia: a language disorder which a person has difficulty in understanding written and spoken language and producing meaningful written and spoken language (often referred to as receptive aphasia). Results from damage to Wernicke’s area which is located in the left temporal lobe (near the parietal lobe boundary). Individuals have little or no awareness of their condition. Has the following characteristics: o Speech is articulate and syntactically correct, but meaningless (nonsense words and syllables may be used, or there may be mispronunciation of words). o Have difficult selecting the correct words to express their ideas. o Difficulty comprehending both written and spoken language.

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Unit 3: The conscious self » Comparison Location of brain damage

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Broca’s aphasia Left frontal lobe near motor cortex Difficulty expressing themselves in words or sentences but their ability to understand written and spoken language is largely unaffected Non-fluent, slow, deliberate and effortful Moderate to severe difficulty Moderate to severe

Wernicke’s aphasia Left temporal lobe near parietal lobe boundary Difficulty understanding written and spoken language and producing written and spoken language that makes sense to others Very fluent but makes no sense Mild to severe difficulty Mild to moderate

Language difficulties

Fluency of speech Ability to find and use correct names for words Repetition of words

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» Contribution of Aphasia studies Case studies have shown us that language can be compromised in different ways depending on which area of the brain has been damaged, as well as the severity of it. Aphasia case studies reveal that language and speech functions are primarily performed in the left hemisphere of the brain. Recovery from aphasia offers insights into the way the brain compensates for the damaged area in the brain caused by brain trauma or surgery (it is known that usually nearby areas take over these language functions, though areas in the right hemisphere may also take over). There are limitations to generalising the findings of aphasia case studies: o Our brains are unique and the précis location of Broca’s and Wernicke’s area varies among individuals. o Brain scans reveal that many areas of the brain are associated with language use, however this pattern of brain activation changes depending on the individual and how language is being used at any given moment. o Aphasia results from brain damage, usually due to a stroke. Because the extent of brain damage varies between people, the effect on language varies in different people.

Spatial Neglect
 Spatial neglect (neglect syndrome): a disorder in which an individual ignores stimuli on one side of their body (damage occurs usually in the right posterior parietal lobe, due to spatial tasks being specialised in the right hemisphere, resulting in stimuli on the left side being ignored). Occurs after brain injury (caused by stroke or brain injury) and relates to visual stimuli. Those suffering from spatial neglect are considered ‘blind’; the eyes function normally however the brain is unable to process visual stimuli normally. Most sufferers are blissfully unaware of their condition (anosognosia) and others may be aware of their condition but show no concern about it (anosodiaphoria). » Contribution of Spatial Neglect studies Spatial neglect has serious impacts of consciousness: it can limit perceptions, thoughts, behaviours and feelings. It has been suggested that a widespread network of areas and neural pathways are involved in the effects of spatial neglect. 25 | P a g e

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Split-brain studies
  Split-brain surgery: an invasive method that involves the severing of the corpus callosum (commisurotomy). Corpus callosum: the thick band of about 200 million nerve fibres connecting the right and left hemispheres. Other than that it connects the two hemispheres, its purpose is to allow the two hemispheres to work in an integrated way despite the fact that the two hemispheres operate differently with different responsibilities. Therefore, this means that information may be constantly exchanged between the two hemispheres enabling both sides of the brain to obtain sensory information simultaneously. Split-brain: a patient’s brain after undergoing brain surgery in which the corpus callosum is severed. Although the cerebral hemispheres are separated, the two sides of the brain are still connected at the region below the cortex (subcortical region). » Roger Sperry & Michael Gazzaniga Sperry and Gazzaniga devised an experimental situation in which different stimuli could be presented to either of a person’s two hemispheres independently, relying on the visual input from the eyes. o Info presented in the right visual field of each eye falls on the left side of each retina and is sent to the left primary visual cortex in the occipital lobe for processing, and vice versa. o Information presented in the centre of the visual field of each eye, falls on the centre of each retina and is processed in both primary visual cortices in the occipital lobes. They used this knowledge of the visual pathways to devise the experimental situation. When the corpus callosum is severed, information presented to one side of the visual field will be processed in one visual cortex and cannot be communicated to the other hemisphere. However split-brain patients move their eyes to allow the visual information to fall on the centre on the retina, and thus, the visual information from each eye is transported to both hemispheres. They may also say things aloud whereby it is then detected by both ears allowing information to be shared between both hemispheres. Sperry’s idea was to present a visual image to one side of the visual field for 1/10 th of a second and therefore patients did not have time to move the eyes ensuring the image fell on only one half of the retina. Patients would sit in front of a screen staring straight ahead and images would be flashed on either the left or right side. Objects were placed behind the screen (out of sight from the patient) but within reach of either hand. The ability of the person to report what they had seen, or respond in other ways provided an indication of what each hemisphere can process. Sperry and Gazzaniga’s Experimental Situation #1 Involved words being presented in the left or right visual fields. Words presented to the right visual field: patients were able to read & report the word verbally. Words presented to the left visual field: patients were unable to report the word verbally; able to select item that represented the word by touch but unable to say why they chose it. Left hemisphere: can identify words and name them. Right hemisphere: can identify words but cannot name them. 26 | P a g e

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Sperry and Gazzaniga’s Experimental Situation #2 Involved words being presented in the left and right visual fields simultaneously and were asked to verbally identify the object or select the object by touch. Words in the right visual field: patients were able to read and verbally report the word. Words in the left visual field: patients were unable to verbally report the word. Left hemisphere: can identify words and name them. Right hemisphere: can process words but cannot name them. Sperry and Gazzaniga’s Experimental Situation #3 Involved pictures of items being presented in the left or right visual fields. Pictures in the right visual field: patients were able to verbally identify the object. Pictures in the left visual field: patients were unable to verbally identify the object; able to select object that represented the word though often denied seeing anything at all. Left hemisphere: can identify pictures and name them; makes decisions concerning whether can item was present or not. Right hemisphere: can identify pictures by touch but cannot name them.

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Conclusions These experiments suggested that the left and right hemispheres have different language skills:  Left hemisphere: more involved in verbal processes and constructing theories about what is going on around them.  Right hemisphere: can process information but can only express the information nonverbally (such as through touch). » Limitations with using split-brain patients Most patients are male and right-handed (generally, right-handed people tend to have their main language centres in their left hemisphere and left-handed people in either their left or right). All patients in the study suffered from epilepsy; this may have affected their performance on such tests; all patients were also on long-term medication. The split-brain surgery itself may have had side effects and exaggerated the results. » Contribution of Split-brain studies Although the brain hemispheres may operate differently, they work in an integrated way, constantly exchanging information through the help of the corpus callosum. Our left hemisphere is more involved in verbal processes and constructing theories about the relationship between perceived events, actions and feelings. The right hemisphere is also capable of verbal processing and can express itself nonverbally.

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Perceptual anomalies
Perception: acts as a filter through which we experience the external world and create our own reality (i.e. the way we experience our world depends on our perception). Perceptual anomaly: refers to irregularities in perception and usually involves an inconsistency between perception and objective reality (some may be experienced by an average person, while others are rarely not).

Motion After-Effect
 Motion after-effect: an optical illusion that involves the apparent movement of a physically stationary visual stimulus following the viewing of a continuously moving stimulus. This stationary stimulus appears to move in the opposite direction to the original moving stimulus. Not limited to visual perception; may include sense of touch (incl. pain, pressure, temperature) Motion detector neurons: specialised neurons that detect movement in certain directions. » Causes Neural adaption: believed to be the cause of the motion after-effect illusion. The visual cortex consists of specific neurons that are designed to perceive motion in certain directions called ‘motion detector neurons’. Staring at a particular motion in a specific direction will trigger the neurons sensitive to this direction, increasing their signals. After a while, these neurons begin to adapt to the motion, causing them to reduce their signals, and the neurons that are sensitive to the opposite motion is higher, and thus this leads a person to incorrectly perceive motion in the opposite direction. » Contribution of motion after-effect studies MAEs show that visual perception does not simply rely on our eyes but also on the way our brain interprets visual stimuli. MAEs may cause our perception to be misled, causing us to perceive events that aren’t really occurring in our environment. Offers a non-invasive way to study the human brain.

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Change Blindness
   Change blindness: the failure to notice a significant alteration that occurs in full view in a visual scene. Change blindness is caused by a lack of attention to details and failure to transfer details to short-term memory. For change blindness to occur, there must be a visual disruption which occurs as the change takes place. o Eye saccades (simultaneous movement of the eyes) o Eye blink o Flicker or blank screen o Mudsplash (brief obstruction) o Very slow change (not a visual disruption, however because the change is made extremely slowly, it is unlikely to grab our attention) Inattentional blindness: a contrasting phenomenon that involves the failure to notice a particular stimulus in a scene, however this occurs without any visual disruption. 28 | P a g e

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» Causes Currently believed that attention and memory are the cause of change blindness. Two different perceptual processes take place when identifying a change: o Sensing that a change has occurred; this requires our attention since our attention is attracted to fast changes, and thus causing us to believe that a change has occurred. o Detecting the change; this requires our memory by recalling the previous scene » Contribution of change blindness studies Change blindness suggests that we can be unaware of major changes in our environment and that the perception of events is not entirely ongoing and complete. Our perceptions rely on us unconsciously ‘filling in the gaps’ to create a continuous and complete sequence of events.

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Synaesthesia
     Synaesthesia: a perceptual experience in which stimulation of one sense produces additional unusual experiences in another sense and is (involuntary and is extremely difficult to suppress). The association is vivid for a long period and is unique from patient to patient Synaesthete: a person who experiences synaesthesia. The stimulation is generally in one direction (e.g. one sound triggers a taste, but that taste does not trigger the sound). This condition can be tested by using an fMRI machine, and providing one stimulus and then observing whether another unrelated sensory area is activated. » Causes The cause is generally believed to be both due to genetics and an increased number of neural connections between regions of the brain that were not lost during childhood. Can also be acquired through brain injury however this is rare and experiences are not as vivid as those developed naturally. » Contribution of synaesthesia studies Allows us to understand the relationship between the mind and body in terms of our perceptions of reality. Synaesthesia is not purely sensory in nature but involves complex cognitive processes.

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Direct Brain Stimulation
DBS
Deep brain stimulation: internal stimulation of the brain. It involves a surgical procedure whereby three components are inserted into a person’s body, usually under local anaesthetic: 1) Implanted pulse generator (IPG) 2) The lead 3) The extension » Advantages  Gives relief of symptoms to patients who have difficulty taking particular medication or who have not responded to medication.  Useful for experimental research in animals (particularly in helping to identify the role of specific areas of the brain). » Disadvantages  It is an invasive procedure that has shown neuropsychiatric side effects (e.g. hallucinations, apathy, cognitive dysfunction, depression)  Electrodes can move slightly during surgery.  It is still in the experimental stages when used to provide relief of symptoms that don’t respond to medication.

TMS
Transcranial Magnetic stimulation: a non-invasive technique that allows researchers to stop or start activity in a specific area of the brain (external stimulation of the brain). » Advantages  Non-invasive technique.  It is able to stimulate and deactivate specific areas of the brain to determine the function of that area and mapping brain function.  Can create ‘virtual lesions’ so that researchers can study the relationship between areas of the brain and behaviour. » Disadvantages  Can only stimulate or deactivate neurons to a maximum of depth of 2 cm.  The diagnostic and therapeutic potential of TMS is still being investigated with mixed results.

Brain Recording and Imaging Techniques
CT/CAT
Computerised (axial) tomography: uses the same technology as an X-ray but is far more advanced; it uses a number of X-ray images to create a high quality three-dimensional computer-enhanced image of the brain. Patients are injected with a substance called ‘contrast’, which highlights the brain’s blood vessels after passing through the bloodstream, and allows interpretation of the CT image. » Advantages  Safe, cost-effective procedure, takes less time to perform than an MRI.  Provides greater clarity and detail of the area being examined than an X-ray. 30 | P a g e

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Researchers may view 2D or 3D images of the structure of the brain. Can identify areas of abnormality in brain structures for those suffering from psychological disorders. Less sensitive to patient movement. » Disadvantages Does not provide information about brain activity or the function of it. Exposes the patient to a lot of radiation, thus frequent use of device is not recommended. Black and white images.

PET
Positron emission tomography: measures the volume and location of blood flow in the brain by tracking a radioactive substance (e.g. radioactive glucose) that has been injected into the person’s bloodstream. » Advantages  Provides information about the function and corresponding location of particular areas of the brain during motor and cognitive tasks.  Non-invasive device and can be used with other devices for greater detail of brain activity (e.g. CT and MRI).  Allows researchers to see the brain in action when a person is under the influence of drugs.  Provides valuable comparisons of a patient’s mental functioning as their disease progresses. » Disadvantages  Expensive; few hospitals have access to one.  Requires highly trained staff to operate the device.  Uses radioactive material to show areas of the brain that are active; though time is often limited due to the short life of the radioactive tracer.  Unsafe for pregnant women due to its use of radioactive substances.

SPECT
Single photon emission computed tomography: an imaging technique using radioactive tracers and a scanner that detects gamma rays. SPECT takes a series of 2D images which are combined to create an accurate 3D image. » Advantages  Cheaper to run than a PET scan.  Provides very good information about the functions of the brain.  Provides 3D images of the brain which can then be digitally manipulated on screen for examination. » Disadvantages  Scans take longer to complete.  Images not as detailed compared to PET.  Uses radioactive tracer.

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Unit 3: The conscious self

AOS 1: Mind, brain and body

MRI
Magnetic resonance imaging: a neuroimaging procedure that uses harmless magnetic fields and radio waves to produce a computer-enhanced image of the brain structure. » Advantages  Produces clear images (detailed 3D computer-enhanced, coloured picture) and provides rich detail of damage or abnormalities.  Does not use X-ray or radioactive substances and therefore does not pose a threat to the patient with repeated exposure as it uses harmless magnetic fields and radio waves. » Disadvantages  Expensive and not commonly available as CT.  Cannot be used on people with internal metal devices as it interferes with magnetic image and may pose a physical risk to the person.  Functional information is very limited as pictures are static and frozen in time.  Some may find the MRI chamber claustrophobic and need to be sedated.  Very loud; earplugs or headphones must be worn.  Patient must lie very still; slightest head movement can disturb the scanner’s magnetic field.

fMRI
Functional magnetic resonance imaging: Same as the MRI except that the fMRI is able to provide information on the functions of the brain by monitoring blood flow and oxygen consumption to reveal areas of greater brain activity. It enables researchers to distinguish brain structures that are less than 1 mm apart, and also produces an image every second to show the location(s) and level of brain activation. » Advantages  Produces a clear, detailed 3D computer-enhanced image of the brain (and other structures of the body) to 1 mm accuracy.  Blood flow and oxygen consumption of a specific area of the brain can be viewed as it occurs. » Disadvantages  Very loud; earplugs or headphones must be worn.  The chamber can be claustrophobic for some patients.  Patient must lie very still; slightest head movement can disturb the scanner’s magnetic field.  Unable to detect which brain receptors are being activated by particular neurotransmitters, drugs and treatment chemicals.  Does not reflect the true complexity of communication processes between regions of the brain.  Accuracy has been questioned as the multiple areas that appear to be most activated during the procedure do not show the sequence of activation (instead they light up together).

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