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BIOPSYCHOLOGY Flashcards

1
Q

What two parts is the nervous system divided into?

A
  • Central nervous system
  • Peripheral nervous system
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2
Q

What is the central nervous system divided into?

A
  • Brain
  • Spinal cord
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3
Q

What is the central nervous system?

A
  • Comprises the brain and spinal cord
  • Receives information from the senses and controls the body’s responses
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4
Q

What is the brain?

A
  • Part of the central nervous system that is responsible for coordinating sensation, intellectual and nervous activity
  • Regulates body temperature, breathing and heart rate
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5
Q

What is the spinal cord?

A
  • Bundle of nerve fibres enclosed within the spinal column and which connects nearly all parts of the body with the brain
  • Ensures that signals from the brain are transmitted to the rest of the body via the PNS
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6
Q

What is the peripheral nervous system (PNS)?

A
  • Part of the nervous system that is outside the brain and spinal cord
  • Transmits messages throughout the whole body from the brain and also relays messages back to the brain
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7
Q

What is the peripheral nervous system divided into?

A
  • Somatic nervous system
  • Autonomic nervous system
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8
Q

What is the somatic nervous system?

A
  • Responsible for carrying sensory and motor information to and from the CNS
  • Controls voluntary movements + processes
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9
Q

What is the autonomic nervous system?

A
  • Governs the brain’s involuntary activities (e.g. stress + heartbeat) + is self-regulating
  • Transmits and receives information from organs
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10
Q

What is the autonomic nervous system divided into?

A
  • Sympathetic nervous system
  • Parasympathetic nervous system
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11
Q

What is the sympathetic nervous system?

A
  • Associated with the ‘fight or flight’ response
  • Prepares the body for physical activity (e.g. running away of fighting)
    ^— increases heart rate + blood pressure
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12
Q

What is the parasympathetic nervous system?

A
  • Relaxes the individual once the emergency has passed
    ^— a.k.a. ‘Rest and digest’ system
  • Regulates bodily functions like digestion + urination
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13
Q

What is meant by the sensory neuron?

A
  • Carries nerve impulses from sensory receptors (e.g. taste, vision, touch) to the spinal cord + the brain
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14
Q

What is meant by the relay neuron?

A
  • Most common type of neuron in CNA
  • Allow sensory + motor neurons to communicate with each other
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15
Q

What is meant by the motor neuron?

A
  • Form synapses with muscles _ control their contractions
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16
Q

Define synaptic transmission

A
  • Refers to the process by which a nerve impulse passes across the synaptic cleft from one neuron (presynaptic neuron) to another (postsynaptic neuron)
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17
Q

What is an action potential?

A
  • Neurons must transmit info both within the neuron + from one neuron to the next
  • The dendrites of neurons receive information from sensory receptors or other neurons
  • This info is then passed down to the cell body + on to the axon
  • Once the information has arrived at the axon, it travels down its length in the form of an electrical signal known as an action potential
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18
Q

Explain the nature of synaptic transmission

A
  • Action potential arrives at the terminal button at the end of the axon + needs to be transferred to another neuron or to tissue
    ^— must cross a gap between the presynaptic neuron and the postsynaptic neuron (called the synapse)
  • Vesicles at the end of the axon of the nerve cell (synaptic vesicles) contain chemical messengers that assist in the transfer of the impulse (neurotransmitters)
  • Action potential reaches synaptic vesicles —> causes them to release their contents through exocytosis
  • Released neurotransmitter diffuses across synaptic gap + binds to specialised receptors on the surface of the cell that recognised + are activated by that neurotransmitter
  • Once activated, receptor molecules produce excitatory or inhibitory effects
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19
Q

Explain what is meant by excitation

A
  • Neurotransmitters are either excitatory or inhibitory
  • Excitatory neurotransmitters increase the likelihood that in excitatory signal is sent to the postsynaptic cell, which is then more likely to fire
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20
Q

Explain what is meant by inhibition

A
  • Neurotransmitters are either excitatory or inhibitory
  • Inhibitory neurotransmitters decrease the likelihood of that neuron firing
  • Responsible for calming the mind + body, inducing sleep
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21
Q

Explain the role of excitatory neurotransmitters

A
  • An excitatory neurotransmitter binding with a postsynaptic receptor causes an electrical change in the membrane of that cell
    ^— results in a excitatory postsynaptic potential (EPSP)
    ^— means that postsynaptic cell is more likely to fire
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22
Q

Explain the role of inhibitory neurotransmitters

A
  • An inhibitory neurotransmitter binds with a postsynaptic receptor
    ^— results in an inhibitory postsynaptic potential (IPSP)
    ^— makes it less likely that the cell will fire
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23
Q

How can

A
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24
Q

What is the endocrine system?

A

A network of glands throughout the body that manufacture + secrete chemical messengers (hormones)

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25
Q

Outline the functions of the endocrine system

A
  • Endocrine glands produce + secrete hormones (chemical substances that regulate cell activity)
  • ## Endocrine system regulated by feedback (like how thermostat regulates room temp)wtaf
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26
Q

State three endocrine glands

A
  • Pituitary gland
  • Adrenal glands
  • Ovaries
  • Testes
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27
Q

List THREE hormones produced by the pituitary gland

A
  • ACTH - stimulates adrenal glands to produce cortisol
  • LH (luteinising hormone)-
  • FSH (follicle stimulating hormone)
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28
Q

Outline the role of the pituitary gland (PG)

A
  • Produces hormones that influence the release of hormones from other glands
    ^— thus regulates many bodily functions
  • PG controlled by hypothalamus
  • High levels of hormones produced in other glands can stop the hypothalamus and pituitary releasing more of their own hormones
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29
Q

List FOUR hormones produced by the adrenal glands

A
  • Cortisol
  • Aldosterone
  • Adrenaline
  • Noradrenaline
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30
Q

Outline the role of the adrenal glands

A
  • Each adrenal gland made up of 2 distinct parts - adrenal cortex (OUTER) and adrenal medulla (INNER)
  • Hormones released by adrenal cortex are necessary for life while those by the adrenal medulla are not
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31
Q

Outline the role of cortisol

A
  • Regulates or supports many important bodily functions
    ^— e.g. cardiovascular + anti-inflammatory functions
  • Production increased in response to stress
  • If low cortisol, individual has low pressure, poor immune function and an inability to deal with stress
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32
Q

Outline the role of aldosterone

A
  • Maintains blood volume + blood pressure
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33
Q

Outline the role of adrenaline

A
  • Helps the body respond to a stressful situation
    ^— e.g. by increasing heart rate + blood flow to the muscles and brain + helping with the conversion of glycogen to glucose to provide energy
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34
Q

Outline the role of noradrenaline

A
  • Constricts the blood vessels causing blood pressure to increase
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35
Q

List TWO hormones released by the ovaries

A
  • Oestrogen
  • Progesterone
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36
Q

Outline the role of the ovaries

A
  • Responsible for the production of eggs

Progesterone: important in post-ovulation + associated with heightened sensitivity to social cues that indicate the presence of social opportunity or threat that would be significant in the case of pregnancy

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37
Q

State the hormone produced by the testes

A

Testosterone

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38
Q

Outline the role of the testes

A
  • Male reproductive glands
  • Testosterone causes development of male characteristics (e.g. facial hair, voice deepening + growth spurt in puberty)
  • T production controlled by hypothalamus + pituitary gland
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39
Q

What is a hormone

A

The body’s chemical messengers - they travel through the bloodstream, influencing many different processes including mood, the stress response + bonding between mother + newborn baby

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40
Q

Explain what is meant by the term ‘fight or flight response’

A
  • Evolved as a survival mechanism
  • Sequence of activity within the body that is triggered when the body prepared itself for defending/attacking (fight) or running away to safety (flight)
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41
Q

Outline the roles of the amygdala and hypothalamus in the ‘fight or flight response’

A
  • When exposed to a threat the amygdala is mobilised: associated sensory signals (see, hear, smell) with emotions associated with fight or flight (fear/anger)
    ^— send distress signal to hypothalamus
  • Hypothalamus communicates w/ the body via sympathetic nervous system
  • Body response involves 2 major systems: acute and chronic
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42
Q

Outline the ‘fight or flight response’ or acute (sudden) stressors

A
  • Sympathetic nervous system is triggered - begins process of preparing the body for rapid action necessary for fight or flight + sends signal to adrenal medulla
  • Adrenaline released into bloodstream: heart beats faster (pushing blood to muscles, heart + other organs), bp increases, breathing more rapid for more oxygen, triggers release of blood sugar (glucose) to supply energy to body part
  • After threat passers, parasympathetic NS dampens stress response, slowing heartbeat + reducing bp, digestion begins again
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43
Q

Outline the ‘fight or flight response’ or chronic (ongoing) stressors

A
  • If threat continues, chronic system kicks in | Adrenaline subsides + hypothalamus activates stress response called HPA axis
  • H - axis relies on hormonal signals to keeps SNS Hypothalamus releases corticotrophin-releasing hormone (CRH) into the bloodstream in response to the stressor
  • P - CRH arrives at the pituitary gland to stimulate release of adrenocorticotrophic hormone (ACTH), which travels to adrenal glands
  • A - ACTH stimulates adrenal cortex to release stress-related hormones (e.g. cortisol). Cortisol causes quick burst of energy + lower pain sensitivity (POSITIVE) and impaired cognitive performance + lower immune response (POSITIVE)
  • Can regulate self: if cortisol too high, H and P initiate a reduction CRH and ACTH
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44
Q

Outline the role of adrenaline in the ‘fight or flight response’

A
  • Causes physiological changes:
    ^— heart beats faster faster, pushing blood to muscles and organs
    ^— blood pressure increases
    ^— breathing more rapid to take in oxygen
    ^— triggers release of glucose to supply energy to part associated with fight-or-flight response
45
Q

What is the HPA axis?

A

Sequence of bodily activity in response to chronic stress
Comprises of the Hypothalamus, the Pituitary gland and the Adrenal glands

46
Q

Explain what is meant by the term ‘localisation of function’

A

The principle that specific functions (e.g. language, memory, hearing, etc) have specific locations within the brain

Specific areas are associated with specific cognitive processes

47
Q

Outline the nature of the motor cortex

A
  • Responsible for the generation of voluntary motor movements
    ^— located in frontal lobe of brain along the precentral gyrus
  • Both hemispheres of the brain have a motor cortex (cortex on one side controls movement on the opposite side
48
Q

Outline the role of the somatosensory cortex

A
  • Detects sensory events arising from different regions of the body
  • Located in parietal lobe, along the postcentral gyrus

Postcentral gyrus dedicated to the processing of sensory info related to touch
- Using info from the skin, somatosensory cortex produces sensations of touch, pressure, pain + temp.
- Cortex on one side receives info from opposite side (like motor cortex)

49
Q

Outline the role of the visual centre in the brain

A
  • Primary visual centre in the brain is located in the visual cortex in the OCCIPITAL LOBE
  • Visual processing actually begins in retina
  • Nerve impulses from retina are transmitted to brain via optic nerve - some impulses travel to areas of the brain involved with coordination of circadian rhythms (majority terminate in thalamus)
    Thalamus - relay station that passes this info to visual cortex
  • Visual cortex in right hemisphere receives input from left-hand side of visual field + vice-versa
  • Cortex contains several areas, processing colour, shape or movement
50
Q

Outline the role of the auditory centre in the brain

A
  • Lies within temporal lobes on both sides of the brain, where the auditory cortex is
  • Auditory pathway begins in cochlea in inner ear (where sound waves are converted to nerve impulses) which travel via auditory nerve to the auditory cortex
  • Stops at brain stem during journey (decodes duration + intensity of a sound) - then the thalamus (relay station)
51
Q

Outline the identification of Broca’s area

A
  • Paul Broca (French neurosurgeon)
  • Patient could understand spoken language but couldn’t speak or express his thoughts in writing
    ^— all such patients had lesions in their left frontal hemisphere
    ^— similar damage to the right did not have the same results
  • Identified a ‘language centre’
52
Q

Outline the role of Broca’s area

A
  • Believed to be critical for speech production
  • Neuroscientists found evidence of activity in this area when people perform cognate tasks that have nothing to do with language
  • Fedorenko et al. (2012) discovered 2 regions of Broca’s area: one involved with language + one involved in responding to many demanding cognitive tasks (e.g. maths)
53
Q

Outline the identification of Wernicke’s area

A
  • Carl Wernicke (German neurologist)
  • Patients could speak but couldn’t understand language
    ^— Wernicke proposed that language involves separate motor and sensory regions located in different cortical regions
54
Q

Outline the role of Wernicke’s area

A
  • Involved in understanding language (in left temporal lobe)
55
Q

What is the motor cortex?

A

Region of the brain responsible for the generation of voluntary motor movements

56
Q

What is the somatosensory cortex?

A

Region of the brain that processes input from sensory receptors in the body that are sensitive to touch

57
Q

What is Broca’s area?

A

An area in the frontal lobe of the brain, usually in the left hemisphere, related to speech production

58
Q

What is Wernicke’s area?

A

An area in the temporal lobe of the brain important to the comprehension of language

59
Q

Explain what is meant by ‘lateralisation’

A

The fact that some mental processes in the brain are mainly specialised to either the left or right hemisphere

60
Q

Explain what is meant by ‘split-brain research’

A

Research studying individuals who have been subjected to the surgical separation of the two hemispheres of the brain as a result of severing the corpus callosum

61
Q

Explain the nature of lateralisation in the brain

A
  • Lateralisation - two halves of the brain aren’t ‘alike’
  • Each hemisphere has functional specialisations (e.g. language is localised primarily in one half of the brain)
  • e.g. research has found L hemisphere is dominant for language + speech while R specialises in visual-motor tasks
  • Broca - damage to his area in L side caused lang. deficits but not in R side
  • Two hemispheres connected by corpus callosum - how we can talk about things (language in L) that happen in the right hemisphere
62
Q

What is the corpus callosum?

A

Connecting bundles of nerve fibres

63
Q

Outline the procedure of split-brain research

A
  • Sperry & Gazzaniga (1967) first to study epileptics who had corpus callosum cut as treatment (split-brain patients)
  • Sent visual info to just one hemisphere at a time to study hemispheric lateralisation
  • In theory: info presented to one hemisphere has no way of travelling to the other + can only be processed in one
  • Split-brain patient would fixate on a dot in the centre of a screen while info was present to either L or R field
    ^— then asked to make responses with either left hand (R hem) or right hand (L hem), or verbally (L hem) without being able to see what their hand were doing
64
Q

Outline the findings of split-brain research

A
  • If dog pic was flashed to right visual field, they would answer correctly
  • If cat pic was flashed to left visual field, they would say they see nothing

Info from L visual field processed by R hemisphere, but it as no language centre (so cannot verbally respond)
^— L hemisphere has a language centre but does not receive info about seeing the cat so cannot say it has seen it

65
Q

What has been learned from split-brain research?

A
66
Q

Explain what is meant by the term ‘plasticity of the brain’

A

The brain’s ability to change and adapt as a result of experience

67
Q

Outline evidence for plasticity in the brain due to life experience

A
  • Boyke et al. (2008) found evidence in 60 year olds taught a new skill - juggling
    ^— found increases in grey matter in the visual cortex (but when practising stopped, these changes were reversed)
  • As people gain new experiences, nerve pathways that are used frequently develop stronger connections - but those rarely used eventually die
  • Also natural decline in cognitive functioning with age that can be attributed to changes in the brain
    ^— researchers looked for ways in which new connections can be made to reverse this effect
68
Q

Outline evidence for plasticity in the brain due to video games

A
  • Kühn et al. (2014) compared control group w/ video game training group that was trained for 2 months for min. 30 mins per day on Super Mario
  • Significant increase in grey matter in various brain areas including the cortex, hippocampus + cerebellum
    ^— this was not evident in the control group
  • Concl. video game training resulted in new synaptic connections in brain areas involved with spatial navigation, strategic planning, working memory + motor performance
69
Q

Outline evidence for plasticity in the brain due to meditation

A
  • Davidson et al. (2004) compared 8 practitioners of Tibetan mediation w/ 10 student volunteers w/ no previous mediation experience
  • Both groups fitted with electrical sensors + asked to meditate for short period
  • Electrodes picked up greater activation of gamma waves in the monks
    ^— students only slight increase
  • Concl. May even have permanent changes, as monks had far more gamma wave activity that control before they started mediating

Gamma waves - coordinate neuron activity

70
Q

Explain what is meant by the term ‘functional recovery’

A

The recovery of abilities and mental processes that have been compromised as a result of brain injury or disease

71
Q

Briefly describe the foundations of functional recovery after trauma

A
  • 1960s - researches studied stroke victims who were able to regain functioning
  • When brain cells are damaged or destroyed, the brain rewires itself over time so some level of function can be regained
  • Event bough some parts of the brain may be damaged/destroyed, other parts can take over the functions that were lost
72
Q

State the two ways the brain is able to functionally recover

A
  • Neuronal unmasking
  • Stem cells
73
Q

Explain and give evidence for neuronal unmasking in functional recovery

A
  • Wall (1977) identified ‘dormant synapses’ in the brain
    ^— synaptic connections hat exist anatomically but their function is blocked
  • Under normal conditions, these synapses may be ineffective as the rate of neural input to them is too low for activation
  • Increasing rate of input to them (e.g. when surrounding area is damaged) can open thissynapses
  • Unmasking dormant synapses can open connections to regions of the brain that are not normally activated, allowing the development of new structures
74
Q

Outline the role of stem cells in functional recovery

A

Stem cells - unspecialised cells which have the potential to become different cell types that carry out different functions

  • Views that stem cells implanted into the brain would directly replace dead or dying cells
  • OR transplanted stem cells secrete growth factors that can ‘rescue’ the injured cells
  • OR transplanted cells form a neural network, linking an uninsured brain site with the damaged region
75
Q

State FOUR ways of studying the brain

A
  • Post-mortem examinations
  • Functional magnetic resonance imaging (fMRI)
  • Electroencephalogram (EEG)
  • Event-related potentials (ERPs)
76
Q

Outline the nature of post-mortem examinations as a way of studying the brain

A
  • Used to establish underlying neurobiology of a behaviour
    ^— e.g. studying a person who displays behaviour while alive that suggests possible underlying brain damage | when they die, researchers can examine their brains to look for abnormalities that may explain
    ^—— e.g. Broca did so with a patient who displayed speech problems while alive + had a lesion in the area of the brain ‘Broca’s area’
77
Q

Outline the nature of functional magnetic resonance imaging (fMRI) as a way of studying the brain

A
  • Technique for measuring changes in brain activity - detects changes in blood oxygenation and flow that indicate increased neural activity
    ^— If a particular area of the brain becomes more active, there is an increased demand for oxygen in that area - brain responds do demand by increasing blood flow, delivering oxygen in red blood cells
  • Researchers can therefore produce maps showing which areas of the brain are involved with a particular mental activity
78
Q

Outline the nature of electroencephalograms (EEGs) as a way of studying the brain

A
  • EEG measures electrical activity in the brain
    ^— electrodes placed on scalp detect small electrical changes resulting from activity of brain cells - graphing of signals over period of time results in EEG
  • EEG data can be used to detect various types of brain disorder (e.g. epilepsy) or do diagnose other disorders affecting brain activity (e.g. Alzheimer’s)
  • In epileptics, EEG readings show spikes of electrical activity | EEG patterns in patients with brain disease + brain injury show overall slowing of electrical activity
79
Q

Name the four basic EEG patterns

A
  • Alpha waves
  • Beta waves
  • Delta waves
  • Theta waves
80
Q

When are alpha waves recorded in EEGs?

A

When a person is awake but relaxed

RHYTHMICAL ALPHA WAVES

81
Q

When are beta waves recorded in EEGs?

A

When the person is physiologically aroused
Also REM sleep (rapid eye movement)

LOW AMPLITUDE + FAST FREQUENCY BETA WAVES

82
Q

When are delta and theta waves recorded in EEGs?

A
  • Occur during sleep
  • Moving for light to deep sleep, occurrence of alpha waves decreases + replaced by lower frequency theta waves - then delta waves
83
Q

Outline the nature of event-related potentials (ERPs) as a way of studying the brain

A
  • Very small voltage channels in the brain that are triggered by specific events or stimuli (e.g. cognitive processing of a specific stimulus)
  • Difficult to pick out from all other electrical activity being generated within the brain at a given time
84
Q

How can ERPs be divided?

A
  • Sensory ERPs
  • Cognitive ERPs
85
Q

What is a sensory ERP?

A

Waves occurring WITHIN the first 100 milliseconds after presentation of the stimulus
^— reflects an initial response to the physical characteristics of the stimulus

86
Q

What is a cognitive ERP?

A

Waves occurring AFTER the first 100 milliseconds
^— reflects the manner in which the subject evaluates the stimulus

87
Q

What are circadian rhythms?

A
  • A pattern of behaviour that occurs or recurs approximately every 24 hours, and which is set + reset by environmental light levels
  • Driven by our ‘body clocks’
88
Q

Give three examples of a circadian rhythm

A
  • The sleep-wake cycle
  • Core body temperature
  • Hormone production
89
Q

Outline one example of a circadian rhythm

A
  • Circadian rhythm dictates when we should sleep + be awake
    ^— light + darkness are the external signals that determine when we feel the need to sleep and when to wake up
  • Rhythm dips + rises at different times of the day - strongest sleep drive occurs in TWO ‘dips’: between 1-4AM and between 1-3PM (post-lunch dip) | Sleepiness during these dips is less intense if we get enough sleep
90
Q

Outline the nature of a circadian rhythm

A
  • A biological rhythm that are cyclical changes in the way biological systems behave
  • Driven by our body clocks (found in all cells of the body) + synchronised by master circadian pacemaker: suprachiasmic nuclei (SCN) found in hypothalamus
  • Light is the primary input for this system
91
Q

Outline one research study that has investigated circadian rhythms

A
  • Siffre (1962, 1999) has often spent long periods of time living underground to study his own circadian rhythms - no external cues (daylight, clocks or radio) - he just woke, ate and slept
  • 1962: Spent 61 days in southern Alps, resurfaces on 17 September believing it was 20 August
  • 1999: interested in effects of ageing on circadian rhythms (was 60 years old by this time)
    ^— found body clock ticked more slowly compared to when he was young - stretching circadian rhythms or 48 hours
92
Q

What are ultradian rhythms?

A

Cycles that last less that 24 hours

93
Q

Give two examples of ultradian rhythms

A
  • Sleep stages (REM, NREM)
  • Basic Rest Activity Cycle (BRAC)
94
Q

Outline the sleep stages as an example of ultradian rhythms

A
  • Follows a pattern of alternating REM (rapid eye movement) + NREM (non-repaid eye movement) sleep
    ^— consists of stages 1 through to 4 (cycle repeats every 90-100 minutes through the night)
  • Cycle consists of progression through 4 stages of NREM before entering REM

Stage 1: light sleep | Stage 2: breathing pattern + heart rate slows | Stage 3: deep sleep | Stage 4: Very deep sleep | Stage 4: REM

95
Q

Outline the BRAC as an example of ultradian rhythms

A
  • Kleitman (1969) referred to 90 minute cycle found during sleep as BRAC
    ^— also suggested the 90 minute rhythm continues during the day, even when awake: instead of sleep stages, we move progressively form state of alertness into a state of physiological fatigue approx. every 90 mins
  • Research suggests the human mind can focus for a period of about 90 mins before body runs out of resources
96
Q

What are infradian rhythms?

A

Rhythms that have a duration of over 24 hours, and may be weekly, monthly or even annually

97
Q

Give three examples of infradian rhythms

A
  • Weekly rhythms
  • Monthly rhythms: human menstrual cycle
  • Annual rhythms
98
Q

Outline weekly infradian rhythms

A
  • Male testosterone levels are elevated at weekends + young couples report more sexual activity at weekends that weekdays | BUT frequency of births at weekends is lower than weekdays
  • Halberg et al. (2002) reported seven-day rhythms of blood pressure + heart rate in humans
99
Q

Outline monthly infradian rhythms

A
  • Mentrual cycle lasts about one month (mensis = Latin for month)
    ^— this varies (23-36 days oftentimes)
  • Menstrual cycle regulated by hormones, which either promote ovulation or stimulate the uterus for fertilisation
100
Q

Outline annual infradian rhythms

A
  • In most animals, annual rhythms are related to the seasons (e.g. migration as a response to lower temperatures + decreased food sources in winter)
    ^— humans: calendar year appears to influence behaviour regardless of temperature changes
  • Magnusson (2000) suggests seasonal variation in mood in humans (especially women) - SAD (season affective disorder) - increased depression during winter months
  • Winter also associated with increase in heart attacks, which varies seasonally + peaks in winter (Trudeau, 1997)
101
Q

What are endogenous pacemakers?

A

Mechanisms within the body that govern the internal,biological bodily rhythms

102
Q

Name the most important pacemaker in human beings

A

Suprachiasmatic nucleus

103
Q

What is the suprachiasmatic nucleus?

A
  • Lies within the hypothalamus
    ^— plays an important role in generating the body’s circadian rhythm, acting as a ‘master clock’, linking to other brain regions that control sleep + arousal (has control over other biological clocks in the body)
  • Neurons in the SCN spontaneously synchronise w/ each other so their target neurons in sites elsewhere receive correctly time-coordinated signals
  • SCN has a built-in circadian rhythm, which only needs resetting when external light levels change (receive info via optic nerve) - even happens when eyes shut
    ^— if our bio clock is running slow (sun rises earlier than previous day), morning light automatically adjusts the clock
104
Q

What is the pineal gland?

A
  • An endogenous pacemaker
  • SCN sends signals to the pineal gland, directing it to increase production + secretion of hormone melatonin at night + to decrease it as light levels increase @ morning
105
Q

What is melatonin?

A

Induces sleep by inhibiting the brain mechanisms that promote wakefulness

106
Q

What is an exogenous zeitgeber?

A

An environmental cue, such as light, that helps to regulate the biological clock in an organism

107
Q

Outline light as an exogenous zeitgeber

A
  • receptors in the SCN are sensitive to light changes during the day + use this info to synchronise the activity of the body’s organs + glands
  • Light resets the internal bio clock each day, keeping it on a 24-hour cycle
  • Rods + cones in the retina of the eye detect light to form visual images
  • Melanopsin (protein sensitive to natural light) is critical in light detection
108
Q

Outline social cues as exogenous zeitgebers

A
  • Social stimuli (e.g. mealtimes + social activities) may also have a role as zeitgebers
  • Aschoff et al. (1971) showed that individuals are able to compensate for the absence of zeitgebers (natural light) by responding to social zeitgebers instead
  • Klein + Wegmann (1974) studied jet lag + found that the circadian rhythms of air travellers adjusted more quickly if they went outside more at their destination (thought to be bcs they were exposed to social cues of their new time zone)

Psychology (19 decks)

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