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Biopsychology Flashcards

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1
Q

Central Nervous System

A
  • CNS consists of the brain + spinal cord
  • It has 2 main functions: the control of behaviour + the regulation of the body’s physiological processes
  • In order to do this the brain must be able to receive information from the sensory receptors (eyes, ears, skin etc.) + be able to send messages to the muscles and glands of the body in response
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2
Q

The brain is divided into 4 main areas:

A

A) Cerebrum
B) Cerebellum
C) Diencephalon
D) Brain stem

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3
Q

Cerebrum

A
  • This is the largest part of the brain
  • It has 4 lobes + is spilt down the middle into 2 halves called the right and left hemisphere
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4
Q

Cerebellum

A

Responsible for motor skills, balance + coordinating the muscles to allow precise movements

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5
Q

Diencephalon

A

Contains the thalamus (regulates consciousness, sleep and alertness) + the hypothalamus (regulates body temperature, stress response and hunger and thirst)

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6
Q

Brain stem

A

Regulates breathing + heart rate

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7
Q

The Spinal Cord

A
  • The main function of the spinal cord is to relay info between the brain + the rest of the body
  • This allows the brain to monitor and regulate bodily processes such as digestion and breathing and co-ordinate voluntary movement
  • The spinal cord is connected to different parts of the body by pairs of spinal nerves which connect to specific muscles and glands
  • If the spinal cord is damaged, body areas connected to it by nerves below the damage will be cut off + stop functioning
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8
Q

The Peripheral Nervous System (PNS)

A
  • PNS consists of the nervous system throughout the rest of the body (not the brain or spinal cord)
  • The PNS transmits messages via neurons (nerve cells) to and from the CNS
  • The PNS has 2 divisions: the somatic nervous system + the autonomic nervous system
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9
Q

The Somatic Nervous System (SNS)

A
  • SNS controls voluntary movements + is under conscious control
  • It connects the senses with the CNS + has sensory pathways AND motor pathways
  • It controls skeletal muscles
  • The somatic nervous system is controlled by the motor cortex
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10
Q

The Autonomic Nervous System (ANS)

A
  • ANS is involuntary (not under conscious control)
  • It ONLY has motor pathways + it controls smooth muscles and the internal organs and glands of the body
  • The ANS is controlled by the brain stem
  • It has 2 sub divisions: sympathetic nervous system + parasympathetic nervous system
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11
Q

Sympathetic Nervous System

A
  • This is activated when a person is stressed
  • Heart rate and breathing increase, digestion stops, salivation reduces, pupils dilate + the flow of blood is diverted from the surface on the skin (fight or flight response)
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12
Q

Parasympathetic Nervous System

A
  • This is activated when the body is relaxing + so conserving energy
  • Heart rate and breathing reduce, digestion starts, salivation increases and pupils constrict
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13
Q

Neurones

A

Neurons are specialised nerve cells that move electrical impulses to and from the CNS

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14
Q

There are several parts to a neuron:

A
  • Cell Body
  • Nucleus
  • Dendrites
  • Axon
  • Myelin Sheath
  • Schwann cells
  • Nodes of Ranvier
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15
Q

Cell body

A

Controls centre of the neurone

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16
Q

Nucleus

A

Contains genetic material

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17
Q

Dendrites

A

Receives an electrical impulse (action potential) from other neurons or sensory receptors e.g. eyes, ears, tongue and skin

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18
Q

Axon

A

A long fibre that carries the electrical impulse from the cell body to the axon terminal

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19
Q

Myelin Sheath

A

Insulating layer that protects the axon + speeds up the transmission of the electrical impulse

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20
Q

Schwann cells

A

Make up the myelin sheath

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21
Q

Nodes of Ranvier

A

Gaps in the myelin sheath + they speed up the electrical impulse along the axon

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22
Q

Sensory Neuron

A
  • Are found in sensory receptors
  • They carry electrical impulses from the sensory receptors to the CNS (spinal cord and brain) via the PNS
  • Sensory neurons convert information from sensory receptors into electrical impulses
  • When these impulses reach the brain they are converted into sensations such as heat, pain so that the body can react appropriately
  • Some sensory impulses terminate at the spinal cord
  • This allows reflexes to occur quickly without the delay of waiting for the brain to respond
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23
Q

Motor Neuron

A
  • Motor neurons are located in the CNS but project their axons outside of the CNS
  • They send electrical impulses via long axons to the glands + muscles so they can affect function
  • Glands and muscles are called effectors
  • When motor neurons are stimulated they release neurotransmitters that bind to the receptors on muscles to trigger a response which leads to movement
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24
Q

Relay Neuron

A
  • Relay neurons are found in the CNS
  • They connect sensory neurons to motor neurons so that they can communicate with one another
  • During a reflex arc e.g. you put your hand on a hot hob, the relay neurons in the spinal cord are
    involved in an analysis of the sensation + decide how to respond e.g. to lift your hand, without waiting for the brain to process the pain
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25
Q

Synaptic Transmission

A
  • Neurons transmit electrical impulses (known as action potentials) between the pre-synaptic neuron + the post-synaptic neuron
  • Synaptic transmission takes only a fraction of a second with the effects terminated by a process called re-uptake
  • The neurotransmitter is taken back by the vesicles on the pre-synaptic neuron where they are stored for later release
  • The quicker the neurotransmitter is taken back the shorter the effects
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26
Q

Pre synaptic neuron

A

The neuron transferring the action potential

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27
Q

Post synaptic neuron

A

The neuron receiving the action potential

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28
Q

Exocytosis

A
  • When the action potential reaches the pre-synaptic terminal it triggers the release of neurotransmitters (chemical messengers) from sacs on the pre-synaptic membrane known as vesicles in a process called exocytosis
  • The released neurotransmitter will diffuse across the synaptic cleft (physical gap between the pre-synaptic membrane + post-synaptic membrane) where it binds to specialised post-synaptic receptor sites
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29
Q

Excitatory neurotransmitters

A
  • Neurotransmitters can be excitatory or inhibitory
  • Most can be both but GABA is purely inhibitory
  • Excitatory neurotransmitters causes an electrical charge in the membrane of the post-synaptic neuron resulting in an excitatory post synaptic potential (EPSP), meaning that the post-synaptic neuron is more likely to fire an impulse
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30
Q

Inhibitory neurotransmitters

A

Inhibitory neurotransmitters cause an inhibitory post synaptic potential (IPSP), making it less likely that the neuron will fire an impulse

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31
Q

Summation

A
  • A neuron can receive both EPSPs + IPSPs at the same time
  • The likelihood that the neuron will fire an impulse is determined by adding up the excitatory + the inhibitory synaptic input
  • The net result of this calculation known as summation determines whether or not the neuron will fire an impulse
  • If the net effect is inhibitory the neuron will not fire + if the net effect is excitatory, the neuron will fire
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32
Q

Direction of Synaptic Transmission

A
  • Info can only travel in ONE direction at a synapse
  • The vesicles containing neurotransmitters are ONLY present on the pre-synaptic membrane
  • The receptors for the neurotransmitters are ONLY present on the post-synaptic membrane
  • It is the binding of the neurotransmitter to the receptor which enables the info to be transmitted to the next neuron
  • Diffusion of the neurotransmitters mean they can only go from high to low concentration so they can only travel from the pre synaptic membrane to the post synaptic membrane
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33
Q

Medication

A
  • Psychoactive drugs (medication that affects brain function to alter perception, mood or behaviour) such as SSRIs, work by affecting (increasing or inhibiting) the transmission of neurotransmitters across the synapse
  • Some pain medications mimic the effects of inhibitory neurotransmitters
  • Stimulation of postsynaptic receptors by an inhibitory neurotransmitter results in inhibition of the postsynaptic membrane
  • When an inhibitory neurotransmitter binds to the post-synaptic receptors it makes the post synaptic neuron less likely to fire
  • Due to summation, if inhibitory neurotransmitters are higher than excitatory neurotransmitters they can inhibit an action potential from occurring
  • Therefore, pain medications would decrease the overall activity + reducing brain activity may lead to less pain
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34
Q

Endocrine System

A
  • The endocrine system provides a chemical system of communication in the body via the blood stream
  • Endocrine glands produce + secrete hormones into the bloodstream which are required to regulate many bodily functions
  • The major glands of the endocrine system include the pituitary gland + the adrenal glands
  • Each gland produces different hormones which regulate activity of organs/tissues in the body
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35
Q

Target Cells

A
  • Although hormones come into contact with most cells in the body, they only affect a limited number of cells known as target cells
  • Target cells respond to a particular hormone because they have receptors for that hormone
  • When enough receptor sites are stimulated by that hormone there is a physiological reaction
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36
Q

The Pituitary Gland (PG)

A
  • Located in the brain
  • It produces hormones whose primary function is to influence the release of other hormones from other glands in the body
  • Is controlled by the hypothalamus (a region of the brain just above the pituitary gland)
  • The hypothalamus receives info from many sources about the basic functions of the body
  • The hypothalamus then sends a signal to the PG in the form of a releasing hormone
  • This causes the PG to send a stimulating hormone into the bloodstream to tell the target gland to release its hormone
  • As levels of this hormone rise in the bloodstream the hypothalamus shuts down production of the releasing hormone + the PG shuts down secretion of the stimulating hormone
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37
Q

The pituitary gland has 2 divisions:

A

1) The anterior pituitary gland releases the hormone called ACTH which regulates levels of the hormone cortisol
2) The posterior pituitary gland is responsible for releasing the hormone oxytocin which is crucial for infant/mother bonding

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38
Q

We have 2 adrenal glands situated on top of the kidneys:

A

1) Adrenal Cortex
2) Adrenal Medulla

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39
Q

Adrenal Cortex

A
  • This is the outer section of the adrenal gland
  • It produces the hormone cortisol which is produced in high amounts when someone is experiencing chronic (long-term) stress
  • Cortisol is also responsible for the cardiovascular system + for instance it will increase blood pressure + causes blood vessels to constrict
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40
Q

Adrenal Medulla

A
  • This is the inner section of the adrenal gland which produces adrenaline = the hormone that is needed for the fight or flight response that is activated when someone is acutely (suddenly) stressed
  • Adrenaline increases heart rate, dilates pupils + stops digestion
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41
Q

The Sympathomedullary Pathway

A
  • The sympathetic nervous system is triggered by the hypothalamus
  • The hypothalamus also sends a signal to the adrenal medulla (part of the adrenal glands) which responds by releasing the hormone adrenaline into the bloodstream
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42
Q

What adrenaline does?

A
  • Adrenaline will increase heart rate, constrict blood vessels, increase rate of blood flow, raise blood pressure, divert blood away from the skin, kidneys and digestive system, increase blood supply to the brain and skeletal muscles, and increase respiration and sweating
  • All of this prepares the body for action + fight or flight by increasing blood supply + therefore
    oxygen to skeletal muscles for physical action + increasing oxygen to the brain for rapid response planning
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43
Q

The role of the Parasympathetic Nervous System in fight or flight

A
  • When the threat has passed the parasympathetic nervous system dampens down the stress response
  • It slows down the heartbeat + reduces blood pressure
  • Digestion, which is stopped when the sympathetic NS is active, restarts
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44
Q

Advantage of the Fight or Flight Response (1)

A

The F/F response makes sense from an evolutionary psychology POV because it would have helped an individual to survive by fighting or fleeing a threat

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45
Q

Advantage of the Fight or Flight Response (2)

A
  • Studies supports the claim that adrenaline is essential in preparing the body for stress
  • People who have malfunctioning adrenal glands don’t have a normal F/F response to stress
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46
Q

Disadvantage of the Fight or Flight Response (1)

A
  • Gray (1988) states that the first reaction to stress is not to F/F but freeze
  • This involves the person stopping, looking and listening + being hyper vigilant to danger
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47
Q

Disadvantage of the Fight or Flight Response (2)

A
  • Taylor (2000) found that females tend + befriend in times of stress
  • Tend and befriend refers to the protection of offspring (tend) + seeking out social groups for mutual defence (befriend)
  • Women have the hormone oxytocin which means they are more likely to stay and protect their offspring
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48
Q

Localisation of function

A

Refers to the principle that functions e.g. vision, hearing, memory, etc. have specific locations within the brain

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49
Q

Research has shown:

A
  • That some functions are more localised than others
  • The motor and somatosensory functions are highly localised to particular areas of the cortex
  • Other functions are more widely distributed
  • The language system uses several parts of the brain, although some components such as speech production may be localised (Broca’s Area)
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50
Q

Visual and Auditory Centres

A
  • Visual Centres
  • Auditory Centres
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51
Q

Visual Centres

A
  • The visual cortex processes info such as colour + shape
  • In the occipital lobe of BOTH hemispheres of the brain
  • Visual processing starts in the retina where light enters + strikes the photoreceptors
  • Nerve impulses from the retina are transmitted to the brain via the optic nerve
  • The majority terminate in the thalamus which acts as a relay station, passing the information onto the visual cortex
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52
Q

Auditory Centres

A
  • The auditory cortex processes info such as pitch + volume
  • It lies within the temporal lobe in BOTH hemispheres of the brain
  • The auditory pathway begins in the cochlea in the inner ear where sound waves are converted to nerve impulses which travel via the auditory nerve to the auditory cortex
  • Basic decoding occurs in the brain stem, the thalamus carries out further processing before impulses reach the auditory cortex
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53
Q

Motor and Somatosensory Areas

A
  • The Motor Cortex
  • The Somatosensory Cortex
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54
Q

Motor Cortex

A
  • Is responsible for voluntary movements
  • Located in the frontal lobe of BOTH brain hemispheres
  • Diff parts of the motor cortex control diff parts of the body
  • These areas are arranged logically next to one another
  • Damage to this area can cause a loss of muscle function/paralysis in 1 or both sides of the body (depending on which hemisphere/hemispheres have been affected)
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55
Q

The Somatosensory Cortex

A
  • Is responsible for processing sensations such as pain and pressure
  • It is located in the parietal lobe of BOTH hemispheres
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56
Q

Language Centres

A
  • Broca’s Area
  • Wernicke’s Area
57
Q

Broca’s Area

A
  • This area is named after Paul Broca who treated patients who had difficulty producing speech
  • He found that they had lesions to the LEFT
    hemisphere of the frontal lobe
  • Damage to the Broca’s Area causes Expressive
    Aphasia
  • This disorder affects language production but NOT understanding
  • Speech lacks fluency and patients have difficulty with certain words which help sentences function e.g. ‘it’ and ‘the’
58
Q

Wernicke’s Area

A
  • This area is in the LEFT hemisphere of the temporal lobe
  • Carl Wernicke found that patients with a lesion to this area could speak but were unable to understand language
  • Wernicke concluded that this area is responsible for the processing of spoken language
  • The Wernicke Area is connected to the Broca’s Area by a neural loop
  • Damage to the Wernicke’s Area causes Receptive Aphasia
  • This disorder leads to an impaired ability to understand language
59
Q

Disadvantage of Localisation of Function (1)

A
  • Some functions are more localised than others
  • Motor and somatosensory functions are highly localised to specific areas of the cortex
  • However, higher functions e.g. personality + consciousness are much more widely distributed
  • Functions such as language are too complex to be assigned to just one area + instead involve networks of brain regions
60
Q

Disadvantage of Localisation of Function (2)

A
  • Equipoteniality theory (Lashley, 1930) holds that higher mental functions are not localised
  • The theory also claims that intact areas of the cortex take over responsibility for a specific cognitive function following injury to the area
    normally responsible
61
Q

Disadvantage of Localisation of Function (3)

A
  • Dronkers (2007) re-examined the preserved brains of two of Broca’s patients
  • MRI scans revealed that several areas of the brain had been damaged
  • Lesions to the Broca’s Area cause temporary speech disruption they do not usually result in severe disruption of language
  • Language is a more widely distributed (and less localised) skill than originally thought
62
Q

Disadvantage of Localisation of Function (4)

A
  • Bavelier (1997) found that there are individual differences in which brain areas are responsible for certain functions
  • They found that diff brain areas are activated when a person is engaged in silent reading
  • They observed activity in the right temporal lobe, left frontal lobe + occipital lobe
  • This means that the function of silent reading doesn’t have a specific location within the brain
63
Q

Hemispheric Lateralisation

A

Refers to the notion that certain functions are principally governed by 1 side of the brain

64
Q

Systematic research has demonstrated:

A
  • That in most people language centres are lateralised to the left hemisphere
  • The Broca’s Area was thought to be responsible for the production of speech however this is now thought to involve a wider network than just the Broca’s Area
  • Damage to the Broca’s Area leads to expressive aphasia
  • The Wernicke’s Area is considered to play a vital role in understanding language/interpreting speech
  • Damage to the Wernicke’s Area leads to receptive aphasia
  • The right hemisphere is dominant for visuo-spatial functions + facial recognition
65
Q

Right and Left

A
  • The right hemisphere of the brain is responsible for the left hand side of the body + the left hemisphere is responsible for the right hand side of the body
  • If a patient is experiencing right sided paralysis this means there is lateralised damage to the left hemisphere
66
Q

Corpus Callosum

A
  • The 2 hemispheres are connected by a bundle of nerve fibres known as the corpus callosum which enables information to be communicated between the 2 hemispheres
  • Many researchers suggest that the 2 hemispheres work together to perform most tasks as part of a highly integrated system
67
Q

Advantage of Hemispheric Lateralisation (1)

A
  • It makes sense from an evolutionary perspective
  • It increases neural processing capacity which is adaptive
  • By using 1 hemisphere to engage in a particular task it leaves the other hemisphere free to engage in another function
  • Rogers (2004) found that hemispheric lateralisation in chickens is associated with an ability to perform 2 tasks simultaneously: finding food + being vigilant for predators
68
Q

Advantage of Hemispheric Lateralisation (2)

A
  • Patients who have extensive damage to their left hemisphere can experience global aphasia (loss of speech production + speech comprehension)
  • This suggests that language is lateralised to the left hemisphere
69
Q

Disadvantage of Hemispheric Lateralisation (1)

A
  • JW (a split-brain patient) developed the capacity to speak using his right hemisphere, with the result that they could speak about information presented in either the left visual field or the right visual field (although he was more fluent if information was presented in the left)
  • It would appear that language is not lateralised entirely to the left hemisphere (Turk, 2002)
70
Q

Disadvantage of Hemispheric Lateralisation (2)

A
  • If 1 hemisphere is damaged, undamaged regions on the opposite hemisphere can compensate
  • Danelli (2013) reported the case of EB, a 17-year-old Italian boy who had virtually his entire left hemisphere removed at the age of 2 and a half due to a huge benign tumour
  • EB’s language appeared almost normal in everyday life in terms of vocabulary and grammar
  • However, systematic testing revealed subtle grammatical problems as well as poorer than normal scores on picture naming + reading of loan words (words adopted from another language e.g. cafe)
  • Language function can be largely preserved after removal of the left hemisphere in childhood but the right hemisphere can’t provide by itself a perfect mastery of each component of language
71
Q

Split Brain Research

A
  • In the past surgeons have cut the corpus callosum to prevent the violent electrical activity caused by epileptic seizures crossing from 1 hemisphere to the other
  • Patients who underwent this form of surgery are often referred to as split-brain patients
72
Q

Sperry and Gazzaniga (1968)

A
  • They investigated split-brain patients
  • Info from the left visual field goes into the right hemisphere whereas info from the right visual field goes into the left hemisphere
  • Because in split-brain patients the corpus callosum has been severed there is no way for the info presented to one hemisphere to travel to the other
73
Q

Sperry and Gazzaniga (1968) - Procedure

A
  • Patients are asked to stare at a dot in the centre of a screen + then info is presented in either the left or right visual field
  • They are then asked to make responses with either their left hand (right hemisphere), right hand (left hemisphere) or verbally (left hemisphere) without being able to see what their hands were doing
  • They may be flashed an image of a dog in their right visual field + then asked what they have seen
  • They will be able to answer ‘dog’ because the info will have gone into their left hemisphere where the language centres are
  • If a picture of a cat is shown in their left visual field + they are asked what they have seen they will not be able to say because the info has gone into their right hemisphere which has no language centres
  • However, they can draw a picture of a cat with their left hand because the right hemisphere controls this hand
74
Q

Advantage of Split Brain Research (1)

A

Split-brain research has enabled discoveries of hemispheric lateralisation

75
Q

Advantage of Split Brain Research (2)

A

Experiments on split-brain patients are highly controlled + scientific

76
Q

Disadvantage of Split Brain Research (1)

A
  • Split-brain patients have often had drug therapy for their epilepsy for much longer than others which may affect the way in which their brain works
  • This means the findings of split-brain research cannot be generalised to the target population
77
Q

Disadvantage of Split Brain Research (2)

A

Many studies using split-brain patients have as few as 3 participants making it hard for results to be generalised to the target population

78
Q

Brain Plasticity

A
  • Refers to the brain’s ability to change and adapt as a result of experience
  • Plasticity allows the brain to cope better with the indirect effects of brain damage such as swelling or haemorrhage following a road accident or the damage resulting from inadequate blood supply following a stroke
79
Q

Plasticity - Life Experience

A
  • Nerve pathways that are used frequently develop stronger connections + those that are rarely used eventually die
  • By developing new connections + reducing weak ones the brain is able to adapt to a changing environment
  • However, there is also a decline in cognitive functioning with age attributed to these changes
  • Boyke (2008) taught 60 year olds a new skill (juggling) + this increased grey matter in the visual cortex
80
Q

Plasticity - Video Games

A
  • Kuhn (2014) compared a control group to a group who had been given video game training for at least 30 minutes a day for 2 months on the game ‘Super Mario’
  • They found that playing video games caused a significant increase in grey matter in the visual cortex, hippocampus and cerebellum
  • Playing video games results in new synaptic connections in brain areas involved in spatial navigation, strategic planning, working memory + motor performance
81
Q

Plasticity - Meditation

A
  • Davidson (2004) compared 8 practitioners of Tibetan meditation with 10 students who had no previous meditation experience
  • An EEG picked up greater gamma wave activity in the monks even before they started meditating
  • Gamma waves coordinate neural activity
82
Q

Advantage of Plasticity (1)

A
  • Kempermann (1998) found far more new neurons in the brains of rats in complex environments compared to those housed in basic cages
  • This increase in neurons was most prominent in the hippocampus which is involved in the forming of new long-term memories + the ability to navigate
83
Q

Advantage of Plasticity (2)

A
  • Maguire (2000) measured grey matter in the brains of London taxi drivers using an MRI scan
  • The hippocampus in taxi drivers was significantly larger than a control group + this was positively correlated with the amount of time they had spent as a taxi driver (the extent of their life experience)
84
Q

Functional Recovery

A
  • Is a form of plasticity
  • Following damage caused by trauma, the brain can redistribute or transfer functions usually performed by damaged areas to other, undamaged areas
  • When the brain is still maturing, recovery from trauma is more likely (Elbert et al. 2001), however the brain is capable of plasticity + functional recovery at any age
  • Studies have suggested that women recover from a brain injury quicker than men do
85
Q

Neural Reorganisation

A

Transfer of functions from damaged areas of the brain to undamaged ones can occur = called neural reorganisation

86
Q

Neural Regeneration

A
  • Growth of new neurons and/or connections (axons and dendrites) to compensate for damaged areas can also occur = called neural regeneration
  • Axon sprouting is part of neural regeneration, new nerve endings grow + connect with other undamaged nerve cells to form new neural pathways
87
Q

Physiotherapy

A
  • Spontaneous recovery from a brain injury tends to slow down after a number of weeks
  • So physiotherapy may be required to maintain improvements in functioning
  • Techniques can include movement therapy + electrical stimulation of the brain to counter deficits in motor + cognitive functioning that can be experienced following a stroke
88
Q

Advantage of Functional Recovery (1)

A
  • Phantom Limb Syndrome (PLS) can be used as evidence of neural reorganisation
  • PLS is the continued experience of sensation in a missing limb, as if it were still there
  • These sensations are often unpleasant + even painful
  • PLS is thought to be caused by neural reorganisation in the somatosensory
    cortex that occurs as a result of limb loss (Ramachandran and Hirstein, 1998)
89
Q

Advantage of Functional Recovery (2)

A
  • Hubel and Torten Wisel (1963) sewed 1 eye of a kitten shut + analysed the brain’s cortical response
  • They found that the visual cortex for the shut
    eye was not idle (as was predicted) it continued to process information from the open eye
  • This is further evidence that brain areas can reorganise themselves + adapt their functions
  • However this is not ethical as it uses animal cruelty and causes harm, pain and discomfort to the poor kitten
90
Q

4 ways to study the brain:

A

1) Post Mortem Examinations
2) FMRI
3) EEG
4) ERP

91
Q

Post Mortem Examinations

A
  • Psychologists may study a person who displays an interesting behaviour while they are alive
  • When the person dies, the psychologists look for abnormalities in the brain that might explain their behaviour
  • Post-mortem studies have found a link between brain abnormalities + psychiatric disorders e.g. there is evidence of reduced glial cells in the frontal lobe of patients with depression
92
Q

Advantage of Post Mortem Examinations

A
  • Post-mortem studies allow for more detailed examination of anatomical + neurochemical aspects of the brain than would not be possible with other methods of studying the brain
  • They have enabled researchers to examine deeper regions such as the hippocampus and hypothalamus
93
Q

Disadvantage of Post Mortem Examinations (1)

A
  • Studies using post-mortems may lack validity because people die in a variety of circumstances + at varying stages of disease
  • Similarly, the length of time between death, the post-mortem + drug treatments can all affect the brain
94
Q

Disadvantage of Post Mortem Examinations (2)

A
  • Post-Mortem studies have very small sample sizes (as special permission needs to be granted)
  • This means the sample cannot be said to be representative of the target population + so it is problematic to generalise the findings to the wider population
95
Q

Functional Magnetic Resonance Imaging (FMRI)

A
  • FMRI provides an INDIRECT measure of neural activity
  • It uses magnetic fields + radio waves to monitor blood flow in the brain
  • It measures the change in the energy released by haemoglobin, reflecting activity of the brain (oxygen consumption) to give a moving picture of the brain
  • Activity in regions of interest can be compared during a base line task + during a specific activity
96
Q

Advantage of FMRI (1)

A

FMRIs captures dynamic brain activity as opposed to a post-mortem examination which purely show the physiology of the brain

97
Q

Advantage of FMRI (2)

A

FMRIs have good spatial resolution (refers to the smallest feature that a measurement can detect)

98
Q

Disadvantage of FMRI (1)

A

Interpretation of fMRI is complex + is affected by poor temporal resolution (resolution of a measurement with respect to time), biased interpretation + by the base line task used

99
Q

Disadvantage of FMRI (2) - expensive

A

FMRI research is expensive leading to reduced sample sizes which negatively impact the validity of the research

100
Q

Electroencephalogram (EEG)

A
  • An EEG DIRECTLY measures GENERAL neural activity in the brain usually linked to states such as sleep and arousal
  • Electrodes are placed on the scalp + detect neuronal activity directly below where they are
    placed + differing numbers of electrodes can be used depending on focus of the research
  • When electrical signals from the different electrodes are graphed over a period of time, the resulting representation is called an EEG pattern
  • EEG patterns of patients with epilepsy show spikes of electrical activity
  • EEG patterns of those with brain injury show a slowing of electrical activity
101
Q

Advantage of EEG

A

An EEG is useful in clinical diagnosis e.g. it can record the neural activity associated with epilepsy so that doctors can confirm the person is experiencing seizures

102
Q

Advantage of EEG (2)

A

EEGs are cheaper than an fMRI so can be used more widely in research

103
Q

Disadvantage of EEG

A

EEGs have poor spatial resolution

104
Q

Event Related Potentials (ERP)

A
  • Electrodes are placed on the scalp + DIRECTLY measure neural activity (below where they are placed) in response to a SPECIFIC stimulus introduced by the researcher
  • ERPs are difficult to pick out from all the other electrical activity being generated within the brain
  • To establish a specific response to a target stimulus requires many presentations of this
    stimulus + the responses are then averaged together
  • Any extraneous neural activity that is not related to the specific stimulus will not occur consistently whereas activity linked to the stimulus will
105
Q

Advantage of ERP (1)

A
  • ERPs can measure the processing of a stimulus even in the absence of a behavioural response
  • Therefore it is possible to measure ‘covertly’ the processing of a stimulus
106
Q

Advantage of ERP (2)

A

ERPs are cheaper than an fMRI so can be used more widely in research

107
Q

Advantage of ERP (3)

A

ERPs have good temporal resolution (unlike FMRIs)

108
Q

Disadvantage of ERP (1)

A

ERPs have poor spatial resolution (unlike FMRIs)

109
Q

Disadvantage of ERP (2)

A
  • Only sufficiently strong voltage changes generated across the scalp are recordable
  • Important electrical activity occurring deeper in the brain is not recorded
  • The generation of ERPs tends to be restricted to the neocortex
110
Q

Biological Rhythms

A
  • Are cyclical changes in physiological systems
  • They evolved because the environments in which organisms live have cyclical changes e.g. day/night, summer/winter etc
  • There are 3 types of biological rhythms: circadian, ultradian and infradian
111
Q

Circadian Rhythms (CRs)

A
  • Are any cycle that lasts 24 hours
  • Nearly all organisms possess a biological representation of the 24 hr day
  • These optimise an organism’s physiology + behaviour to best meet the varying demands of the day/night cycle
112
Q

SCN

A
  • Circadian rhythms are driven by the suprachiasmatic nuclei (SCN) in the hypothalamus
  • This pacemaker (controls the rate at which something occurs) must constantly be reset so that our bodies are in synchrony with the outside world
  • Natural light provides the input to this system, setting the SCN to the correct time in a process called photoentrainment
  • The SCN then uses this info to coordinate activity of circadian rhythms throughout the body
113
Q

The Sleep Wake Cycle

A
  • Light and darkness are the external signals that determine when we feel the need to sleep + when we wake up
  • This rhythm dips + rises at different times of the day so that the strongest sleep drives occur between 2:00-4:00am and 1:00-3:00pm
114
Q

Melatonin

A
  • The release of melatonin from the pineal gland is at its peak during the hours of darkness
  • Melatonin induces sleep by inhibiting the neural mechanisms that promote wakefulness
  • Light supresses the production of melatonin
115
Q

Homeostatic Control

A
  • Sleep and wakefulness are also under homeostatic control
  • When we have been awake for a long time homeostasis tells us that the need for sleep is increasing because of the amount of energy used up during wakefulness
  • This homeostatic drive for sleep increases gradually throughout the day, reaching its maximum in the late evening
  • Circadian rhythms keep us awake as long as there is daylight prompting us to sleep as it becomes dark
  • The homeostatic system tends to make us sleepier, the longer we have been awake regardless of whether it is night or day
  • The internal circadian rhythm will maintain a cycle of 24-25 hours even without natural light
116
Q

Advantage of Circadian Rhythms

A
  • One practical application of CRs is chronotherapeutics
  • The time that patients take medication is very important for treatment success
  • It is essential that the right concentration of drug is released in the target area of the body at the time the drug is most needed
  • E.g. the risk of heart attack is greatest during the early morning hours after waking
  • Medications have been developed that are taken before the person goes to sleep but are not released until the vulnerable time of 6:00am
117
Q

Disadvantage of Circadian Rhythms (1)

A
  • Research on CRs has not isolated people from artificial light, because it was believed only natural light affected CRs
  • However, more recent research suggests this might not be true
  • Cziesler (1999) altered participant’s CRs down to 22 hours + up to 28 hours by using artificial light alone
118
Q

Disadvantage of Circadian Rhythms (2)

A
  • There are individual differences in the length of CRs
  • One research study found that cycles can vary from 13 to 165 hours (Czeisler, 1999)
  • Another individual difference in CRs is when people reach their peak
  • ‘Morning people’ prefer to rise early + go to bed early whereas ‘evening people’ prefer to rise late
119
Q

Disadvantage of Circadian Rhythms (3)

A
  • Studies of individuals who live in Artic regions, where the sun does not set in the summer months, show normal sleeping patterns despite the prolonged exposure to light
  • This suggests that there are occasions where the exogenous zeitgeber of light may have very little bearing on our internal biological rhythms
120
Q

Ultradian Rhythms (URs)

A
  • Ultradian rhythms span a period of less than 24 hours e.g. the 5 sleep stages
  • Human sleep follows a pattern alternating between Rapid Eye Movement (REM) sleep (stage 5) + Non-Rapid Eye Movement (NREM) sleep (consists of stages 1, 2, 3, 4)
  • The cycle repeats itself every 90 mins
  • Each stage shows a distinct EEG pattern
  • As the person enters deep sleep their brainwaves slow + their breathing + heart rate decreases
  • During the fifth stage (REM sleep), the EEG pattern resembles that of an awake person
  • It is during this stage that dreaming occurs
121
Q

Basic Rest Activity Cycle (BRAC)

A
  • Kleitman (1969) referred to the 90 min cycle found during sleep as the Basic Rest Activity Cycle
  • He suggested that this 90 min cycle continues
    when we are awake
  • During the day rather than moving through the sleep stages, we move progressively from a state of alertness into a state of physiological fatigue
  • Studies suggest that the human mind can focus for about 90 mins + towards the end of those 90 mins the body begins to run out of resources, resulting in loss of concentration, fatigue + hunger
122
Q

Advantage of Ultradian Rhythms

A
  • Ericsson (2006) found support for the URs
  • They studied a group of elite violinists + found that among this group practise sessions were limited to 90 mins at a time
  • Violinists frequently napped to recover from practise with the best violinists napping more
  • The same pattern was found among athletics, chess players and writers
  • This fits with the BRAC
123
Q

Disadvantage of Ultradian Rhythms

A
  • Tucker (2007) suggests that there are individual differences in URs which are biologically determined + may even be genetic in origin
  • Participants were studied over 11 consecutive days + nights in a lab environment
  • The researchers assessed sleep duration, time taken to fall asleep + the amount of time in each sleep stage
  • They found differences in all of these characteristics
124
Q

Infradian Rhythms (IRs)

A

IRs span a period of longer than 24 hours + they may last weeks, months or even a year e.g. the menstrual cycle

125
Q

Menstrual Cycle

A
  • Lasts for about a month
  • There are considerable variations in the length of this cycle with some women experiencing a 23 day cycle + others a 36 day cycle
  • The average is 28 days
  • Hormones regulate the menstrual cycle
  • Ovulation occurs roughly halfway through the menstrual cycle when oestrogen levels are at their peak + usually lasts for 16-32 hours
  • After ovulation, progesterone levels increase in preparation for the possible implantation of an embryo in the uterus
126
Q

Advantage of Infradian Rhythms

A
  • IRs can affect behaviour
  • Penton-Voak (1999) found that women express a preference for feminised male faces when choosing a partner for a long-term relationship
  • However they showed a preference for masculinised faces during ovulation
127
Q

Disadvantage of Infradian Rhythms

A
  • The menstrual cycle is not only governed by IRs
  • When several women of childbearing age live together + don’t take oral contraceptives, their menstrual cycles synchronise
  • In one study samples of sweat were collected from one group of women + rubbed onto the upper lip of another group of women, their menstrual cycles became synchronised
  • This suggests that the synchronisation is affected by pheromones
  • Pheromones are a chemical substance produced + released into the environment by an animal which affects the behaviour of others of the same species
128
Q

Internal Biological Rhythms

A
  • Our internal biological rhythms must be finely tuned in order to stay in keeping with the outside world
  • To achieve this we have endogenous pacemakers (internal biological rhythms) + exogenous zeitgebers (external cues/factors e.g. light) which reset our biological rhythms every day
129
Q

Endogenous Pacemakers (EP)

A
  • The most important EP is the suprachiasmatic nuclei (SCN)
  • This is a tiny cluster of nerve cells in the hypothalamus
  • The SCN plays an important role in generating CRs
  • It acts as the master clock, linking other brain regions that control sleep and arousal + controlling all other biological clocks throughout the body
130
Q

Neurons in the SCN

A
  • Neurons within the SCN synchronise with each other so that their target neurons in sites elsewhere in the body receive time-coordinated signals
  • These peripheral clocks can maintain a CR but not for very long which is why they are controlled by the SCN
  • This is possible because of the SCN’s built in CR which only needs resetting when external light levels change
  • The SCN receives info about light levels thru the optic nerve
  • If our biological clock is running slow then morning light shifts the clock
131
Q

SCN and the pineal gland

A
  • The SCN also regulates the manufacture + secretion of melatonin in the pineal gland via the interconnecting neural pathway
  • The SCN sends a signal to the pineal gland, directing it to increase production + secretion of the hormone melatonin at night + to decrease it as light levels increase in the morning
  • Melatonin induces sleep by inhibiting the brain mechanisms that promote wakefulness
132
Q

Advantage of Endogenous Pacemakers

A
  • Folkard (1996) studied a uni student (Kate Aldcroft) who spent 25 days in a lab
  • She had no access to the EZs of light to reset the SCN
  • However at the end of 25 days her core temperature rhythm was still at 24 hours
  • This indicates that we DO NOT need the EZs of light to maintain our internal biological rhythms
133
Q

Disadvantage of Endogenous Pacemakers

A
  • Kate Aldcroft’s sleep-wake cycle extended to 30 hours with periods of sleep as long as 16 hrs
  • This suggests that we DO need the EZs of light to maintain our internal biological rhythms
134
Q

Exogenous Zeitgebers (EZs)

A
  • The term exogenous refers to anything whose origins are outside of the organism
  • EZs are environmental events that are responsible for maintaining the biological clock of an organism
  • The most important zeitgebers for most animals is light
135
Q

Melanopsin

A
  • Receptors in the SCN are sensitive to changes in light levels during the day + use this info to synchronise the activity of the body’s organs + glands
  • Light resets the internal biological clock each day keeping it on a 24-hour cycle
  • A protein in the retina of the eye called melanopsin which is sensitive to natural light is critical in this system
136
Q

Out of sync biological rhythms

A
  • When people move to a night shift or travel to a country with a different time zone their EPs try to impose their inbuilt rhythm of sleep (CR) but this is now out of synchrony with the EZ of light
  • Out of sync biological rhythms lead to disrupted sleep patterns, increased anxiety + decreased alertness and vigilance
137
Q

Advantage of Exogenous Zeitgebers (1)

A
  • The vast majority of blind people who still have light perception have normal CRs
  • Blind people without light perception show abnormal CRs
  • This shows the vital role that the EZ of light levels play in maintaining our internal biological rhythms
138
Q

Advantage of Exogenous Zeitgebers (2)

A

Burgess (2003) found that exposure to bright light prior to an east-west flight decreased the time needed to adjust circadian rhythms to local time

139
Q

Disadvantage of Exogenous Zeitgebers

A
  • Studies of individuals who live in Artic regions, where the sun does not set in the summer months show normal sleeping patterns despite the prolonged exposure to light
  • This suggests that there are occasions where the EZ of light may have very little bearing on our internal biological rhythms

Psychology (11 decks)

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