biopsychology 2 Flashcards
1
Q
what does the brain stem do?
A
controls basic life functions (eg breathing, heart rate)
2
Q
what does the cerebellum do?
A
basic motor control, balance and some simple learning
3
Q
what does the cerebrum do?
A
higher functions (emotion, complex perception, thinking)
4
Q
what does localisation of function mean?
A
certain areas of the brain hold particular functions
5
Q
what does a laterised brain function mean?
A
they are concentrated on one side of the brain
6
Q
what does a cross-laterised brain function mean?
A
the right side of the brain controls the left side of the body (in general, brain function is cross-lateralised)
7
Q
what does localisation further assume?
A
if a certain area of the brain becomes damaged through illness or injury, the function associated with that area will also be affected
8
Q
what is the opposing theory to localisation?
A
holistic theory → suggests that all parts of the brain are involved in the processing of thought and action
9
Q
what is the cerebrum?
A
the largest part of the brain. it is divided into two hemispheres (left and right)
10
Q
what is the outermost layer of the cerebrum?
A
the cerebral cortex
11
Q
how does the cerebral cortex link to our sensory systems?
A
each of our sensory systems sends messages to and from this cerebral cortex
12
Q
what are the hemispheres separated by?
A
the corpus callosum (a bundle of fibres)
13
Q
what does the corpus callosum allow?
A
allows messages that enter the right
hemisphere to be conveyed to the left hemisphere and vice versa
14
Q
each hemisphere is divided into…
A
four lobes:
➢ the frontal lobe
➢ the parietal lobe
➢ the temporal lobe
➢ the occipital lobe
15
Q
what does the frontal lobe do?
A
the location for awareness of what we are doing within our environment (our consciousness)
16
Q
what does the parietal lobe do?
A
location for sensory movements
17
Q
what does the occipital lobe do?
A
location for vision
18
Q
what does the temporal lobe do?
A
location for the auditory ability and memory acquisition
19
Q
what are the other areas of the brain?
A
-motor cortex
-somatosensory cortex
-visual cortex
-auditory cortex
language centres:
broca’s and wernicke’s areas
20
Q
MOTOR CORTEX
(function, effects of damage, location)
A
function:
responsible for voluntary movements by sending signals to muscles in the body
effects of damage
may result in loss of control over fine movements
location
-in the frontal lobe (goes across both hemispheres)
-the motor area in the left hemisphere controls movement on right & vice verses
21
Q
SOMATOSENSORY AREA
(function, effects of damage, location)
A
function
receives sensory information from the skin to produce sensations related to pressure, pain, temperature
effects of damage
causes decreased sensory thresholds
location
in the parietal lobe
22
Q
VISUAL CORTEX
(function, effects of damage, location)
A
function
receives and processes visual information.
it contains different parts which process different types of visual information.
effects of damage
damage to the left hemisphere can produce blindness in part of the right visual field in both eyes
location
in the occipital lobe
23
Q
AUDITORY CORTEX
(function, effects of damage, location)
A
function
-analyses and processes acoustic information
-information from the right ear goes primarily to the left hemisphere and information from the left ear goes primarily to the right hemisphere
effects of damage
may produce partial hearing loss
location
in the temporal lobe
24
Q
where are language areas found?
A
predominantly on the left side of the brain
25
**BROCA’S AREA**
(function, effects of damage, location)
**function**
responsible for speech production
**effects of damage**
broca’s aphasia – slow, laboured and disjointed speech
**location**
in the left frontal lobe
26
**WERNICKE’S AREA**
(function, effects of damage, location)
**function**
responsible for speech comprehension
**effects of damage**
causes wernicke’s aphasia
➢ the person struggles to understand language and often produces sentences that are fluent but meaningless
➢ nonsense words (neologisms) may also be produced
**location**
left temporal lobe
27
which case study supports the theory of brain localisation?
phineas gage
28
aim of phineas gage case study:
to explain the cause of Gage’s change of personality
29
method of phineas gage case study:
-an explosion caused a meter length iron pole (tamping iron) to be hurled first through his left cheek
-it passed behind his left eye, and exited his brain and skull from the top of his head
30
results of phineas gage case study:
-he survived, and after months of recovery wanted to regain his job
-before the accident he was seen as God-fearing, kind and reserved
-his personality had changed to someone who was now boisterous, rude and grossly blasphemous
-his friends said he was "no longer gage."
31
conclusion of phineas gage study:
-gage has taught us a great deal about the complexity of psychological processes that occur in the human brain
-he provides evidence of some localisation of function in the brain
32
strengths of the theory of localisation:
-evidence from the case study of phineas gage
-evidence from brain scans (peterson 1988)
33
strength / ao3 - evidence from the case study of phineas gage
P - there is evidence to support the theory from the case study of phineas gage
E - he suffered an accident where a piece of metal damaged most of his left frontal lobe
↳ although he survived, he experienced changes in personality, such as loss of inhibition and increased anger
↳ this suggests that that certain aspects of personality are localised within the frontal lobe
L - this therefore supports the theory that functions in the brain are localised
34
strength / ao3 - evidence from brain scans (peterson 1988)
S - there is evidence to support localisation of function from brain scans
E - peterson (1988) used brain scans to demonstrate how wernicke's area was active during a listening task and broca's area was active during a reading task
L - this supports the idea that that language functions are localised in different areas of the brain and so supports the theory of localisation of function
35
criticisms of the theory of localisation:
-theory of holistic brain function contradicts the theory of localisation
-the placisity of the brain contradicts the theory of localisation
36
ao3 / criticism - theory of holistic brain function contradicts the theory of localisation
P - not all researchers agree with the view that cognitive functions are localised in the brain
E - there is evidence to show that higher cognitive functions are not localised, but instead are distributed in a more holistic way within the brain
↳ lashley (1950) removed 10-50% of the cortex in rats that were learning a maze, no particular area seemed to be more important in terms of the rat's ability to learn the maze
↳ the process of learning seemed to require every part of the cortex
E - from this research, lashley proposed the theory of equipotentiality → suggests that the basic sensory and motor functions are localised, but the higher functions are not
L - this evidence contradicts the theory of localisation
37
ao3 / criticism - the placisity of the brain contradicts the theory of localisation
P - a further argument against localisation is that of plasticity
E - after brain damage, the brain appears to be able to reorganise itself to recover loss in function (although this does not always happen)
↳ intact areas of the cortex could take over responsibility for specific functions following injury to the area normally responsible for that function
L - this theory of plasticity supports the holistic theory (all parts of the brain are involved in processing of thought and action) rather than localisation
38
Albert suffered a stroke to the left hemisphere of his brain. The stroke damaged Wernicke's area and the motor cortex. Use your knowledge of the functions of Wernicke's area and the motor cortex to describe the problems that Albert is likely to experience.
(4 marks)
**wernicke’s area is responsible for speech comprehension** (in the left hemisphere)
↳ albert will be unable to produce coherent speech. his speech will be fluent but will not make any sense
(wernicke’s aphasia)
**the motor centre is responsible for voluntary movement**
↳ as Albert’s left hemisphere is damaged and the motor centre’s functions are cross lateralised, he will have difficulty with movement on his right side
39
what is a seizure?
an electrical disturbance in the brain
40
what is hemispheric lateralisation?
the idea that the two hemispheres of the brain have different functions
41
how did surgeons learn to reduce seizures in epilepsy patients?
-surgeons found that separating the hemispheres meant seizures could be controlled in very severe cases of epilepsy
-this is because they were mainly contained in one hemisphere
42
what medical procedure is used to split the hemispheres of the brain and how is it done?
hemispheric deconnection/commissurotomy/split-brain surgery
the corpus callosum was severed
43
who conducted the split brain research and when?
sperry & gazzaniga (1968)
44
split brain research sample:
He was a doctor working in a hospital in California, USA.
-11 patients who had undergone hemispheric deconnection for epilepsy
-sperry did not sever the corpus callosum of the epileptic patients himself, he was an opportunist
-he compared their functioning to people without epilepsy who had not undergone the procedure
45
what did the spilt brain surgery mean about communication?
messages could not be sent from one hemisphere to another
46
method of split brain research:
sperry used a tachistoscope to split the visual field & present information to either the left visual field (processed by the right hemisphere) or the right visual field (processed by the left hemisphere)
the information was presented for about 1/10th of a second
sperry and gazzaniga conducted many different experiments, including describe what you see tasks, tactile tests, and drawing tasks.
1) in the describe what you see task, a picture was presented to either the left or right visual field and the participant had to simply describe what they saw
2) in the tactile test, an object was placed in the patient's left or right hand and they had to either describe what they felt, or select a similar object from a series of alternate objects
3) finally, in the drawing task, participants were presented with a picture in either their left or right visual field, and they had to simply draw what they saw
47
FINDINGS:
describe what you see: picture presented to the right visual field
(processed by left hemisphere)
the patient could describe what they saw, as language production is mainly localised in the left hemisphere
48
FINDINGS:
describe what you see: picture presented to the left visual field
the patient could not describe what was shown and often reported that there was nothing present
↳ because the image was processed in the right hemisphere and there are no language centres here
49
FINDINGS:
tactile tests: objects placed in the right hand
(processed by the left hemisphere)
-the patient could describe verbally what they felt, or they could identify the test object presented in the right hand (left hemisphere), by selecting a similar appropriate object, from a series of alternate objects
50
FINDINGS:
tactile tests: objects placed in the left hand
(processed by the right hemisphere)
-the patient could not describe what they felt and could only make wild guesses
-however, the left hand could identify a test object presented in the left hand (right hemisphere), by selecting a similar appropriate object, from a series of alternate objects
51
FINDINGS:
drawing tasks: picture presented to the right visual field
(processed by left hemisphere)
-while the right-hand would attempt to draw a picture, the picture was never as clear as the left hand
52
FINDINGS:
drawing tasks: pictured presented to the left visual field
(processed by right hemisphere)
-the left-hand (controlled by the right hemisphere) would consistently draw clearer and better pictures than the right-hand (even though all the participants were right-handed)
-this demonstrates the superiority of the right hemisphere when it comes to visual motor tasks.
53
FINDINGS:
composite words: (key / ring)
-they would say ring as that is processed by the left hemisphere (has language areas)
-they would be able to pick up the key with their left hand as that was processed by the right hemisphere
54
conclusion of the split brain research study:
-the findings of sperry and gazzaniga's research highlights a number of key differences between the two hemispheres
↳ the left hemisphere is dominant in terms of speech and language
↳ the right hemisphere is dominant in terms of visual-motor tasks
-it seems that in these patients the hemispheres of the brain process information separately
-
55
what type of experiment did sperry use?
a quasi (natural) experiment
56
strength of sperry’s study:
high internal validity
57
ao3 / strength - high internal validity
P - the research conducted by Sperry in split brain patients has high internal validity.
E - sperry used specialist equipment (a tachistoscope) and devised a whole series of tasks to examine the functioning of the split-brain → this means that the tests were carried out in a consistent and controlled way
L - this means that the researchers were measuring what they claimed to measure (lateralisation of function), which increases the internal validity of split-brain research
58
criticisms of sperrys study:
-the research may not be applicable to split brain patients in everyday life
-much of the research is flawed
59
ao3 / criticism - the research may not be applicable to split brain patients in everyday life
P - the research may not be applicable to split brain patients in everyday life
E - in real life, patients with a split brain would adjust their visual position so that information would enter both hemispheres of the brain. we would not see the results of these experiments in everyday life
L - this means that the data about split brain patients and lateralisation of function is artificial and could be said to lack ecological validity
60
ao3 / criticism - much of the research is flawed
P - a weakness of research into hemispheric lateralistaion is that much of the research is flawed
E - sperry’s split-brain research has low generalisability. in his original study he only focused on 11 patients, all of whom had epilepsy → this research takes an idiographic (individual) approach
↳ furthermore, the split-brain procedure is rarely carried out now, so patients are hard to come by
L - this means it is difficult to generalise the findings to a healthy population and therefore we do not know that sperry’s results apply beyond the small sample of epileptic patients originally tested.
61
criticisms of lateralisation;
62
split brain patients show unusual behaviour when tested in experiments. briefly explain how unusual behaviour in split brain patients could be tested in an experiment. (2 marks)
1) set-up a split visual field using a tachistoscope
2) show a stimuli such as words or a picture
3) give the patient a task (verbal, drawing)
63
what is plasticity?
refers to the brain’s ability to change and adapt because of experience
64
what is functional recovery?
the transfer of functions from a damaged area of the brain to other undamaged areas after trauma
65
plasticity of the brain:
-when we are aged 2-3 we have around 15,000 synaptic connections but as we age, synaptic pruning means that rarely used connections are deleted and frequently used connections are strengthened
-it was previously thought that the adult brain, having moved beyond a critical period, remained static and fixed in terms of its functions and structure
66
is neural organisation only changed due to aging?
no, there are many different types of experience that can affect it
(eg: video games & meditation)
67
is plasticity always positive?
plasticity can be negative
eg;
-prolonged drug use leading to poorer cognitive functioning
-old is associated with dementia
(both are due to changes in the brain)
68
research evidence: meditation
-davidson et al (2004) studied tibetan monks and compared them to non-meditation controls
-the monks showed a significant increase in gamma wave activity (which helps to coordinate neuron activity)
-the control group did show an increase when they meditated, but much less so than monks who had been meditating for years
69
research evidence: video games
-a study by Kuhn (2014) found an increase in grey matter in those that played super mario for 30 mins per day for 2 months
-this shows that gaming resulted in new synaptic connections and brain activity for things such as cognitive functioning, motor skills and spatial navigation
70
what is the key study for plasticity?
maguire taxi cab study (2000)
71
context of the maguire study:
as part of their training, london cabbies must take a complex test called ‘the knowledge’, which assesses their recall of the city streets and possible routes
72
maguire's study: aim
to investigate the role of the hippocampus in spatial memory
73
maguire's study: participants
16 healthy, right-handed male licensed london taxi drivers
74
maguire's study: method
matched pairs design: participants were matched with a control group
-two different types of MRI scanning were used to assess how the brains of the taxi drivers differed from the control group
75
maguire’s study: results
1) the hippocampi of taxi drivers were significantly larger than those of control subjects
2) the hippocampal volume correlated with the amount of time spent as a taxi driver (i.e. the longer the participant had been working, the bigger his hippocampus was)
76
strengths of plasticity:
-there is research to support the notion of brain plasticity (maguire)
-further research supports plasticity
-research into understanding the processes involved in plasticity has contributed to the field of neurorehabilitation
77
ao3 / strength - there is research to support the notion of brain plasticity (maguire)
P - there is research to support the notion of brain plasticity
E - maguire et al. found that the posterior hippocampal volume of london taxi drivers’ brains was positively correlated with their time as a taxi driver and that there were significant differences between the taxi
drivers’ brains and those of controls
↳ this shows that the brain can permanently change in response to
frequent exposure to a particular task and supports the theory of plasticity
L - however, we can’t be sure that the difference is due to experience as they weren’t tested before
↳ they could have been taxi drivers because of their already existing difference
78
ao3 / strength - further research supports plasticity
P - further research has supported plasticity
E - kuhn et al found a significant increase in grey matter in various regions of the brain after participants played a video game for 30 minutes a day over a two-month period
↳ also, davidson et al. found permanent change in the brain generated by prolonged meditation (buddhist monks who meditated frequently had a much greater activation of gamma waves (which coordinate neural activity) than did students with no experience of meditation)
L - the two studies highlight further support for the theory of plasticity and the brain’s ability to adapt as a result of new
experience
79
ao3 / strength - research into understanding the processes involved in plasticity has contributed to the field of neurorehabilitation
P - understanding the processes involved in plasticity is has contributed to the field of neurorehabilitation
E - following illness or injury to the brain, spontaneous recovery tends to slow
down after a number of weeks, forms of physical therapy may be required to maintain improvements in functioning
↳ techniques may include movement therapy or electrical stimulation of the
brain to counter the deficits in motor or cognitive functioning
L - research has helped to show that although the brain may have the capacity to ‘fix itself’ to a point, this process requires further intervention to be completely
successful.
↳ this neurorehabilitation demonstrates the positive application of research to help improve the cognitive functions of people suffering from injuries
80
criticisms of plasticity:
some psychologists suggest that research investigating the plasticity of the brain is limited
81
ao3 / criticism - some psychologists suggest that research investigating the plasticity of the brain is limited
P - some psychologists suggest that research investigating the plasticity of the brain is limited
E - for example, maguire’s research is biologically reductionist and only
examines a single biological factor (the size of the hippocampus) in relation to spatial memory.
↳ this approach ifails to take into account all of the different biological/cognitive processes involved in spatial navigation which may limit our understanding
L - other psychologists suggest that a holistic approach to understanding complex human behaviour may be more appropriate
82
what is negative plasticity?
when plasticity results in negative consequences … there is maladaptive
plasticity
83
examples of negative plasticity:
-prolonged drug use has been shown to result in poorer cognitive functioning & increased risk of dementia in later life
-60-80% of amputees have been known to develop phantom limb syndrome (the continued experience of sensations in the missing limb as if it were still there)
84
what happens after physical injury?
-unaffected areas can sometimes compensate for damaged areas
-the functional recovery that occurs in these cases is an example of neural plasticity
-neuroscientists suggest that this can happen quickly after trauma (spontaneous recovery) and then slow down after several weeks or months → therapy may then be needed
85
what happens in the brain during recovery?
1) neuronal unmasking
2) axonal sprouting
3) recruitment of homologous areas
4) reformation of blood
86
neuronal unmasking:
-dormant synapses in the brain are inactive because of low neural input
-they are activated when a nearby area becomes damaged and neural input increases (they are unmasked)
-this opens new connections in the brain / creates new neural pathways
87
axonal sprouting:
-undamaged axons can also sprout (grow) nerve endings and connect with other undamaged nerve cells
-this makes new neural pathways to accomplish what was a damaged function
88
recruitment of homologous areas:
-a connection is damaged and cannot
be used
-another suitable and similar pathway from the opposite hemisphere is ‘recruited’ and helps out
89
example of recruitment of a homologous area:
-if broca’s area was damaged which is on the LEFT side of the brain, then a similar area on the RIGHT side of the brain would carry out its functions for a period of time
-it would then switch back to the LEFT if/when it has recovered
90
reformation of blood:
the blood supply is rerouted to other
areas of the brain
91
strengths of functional recovery:
-there is research to support the claim for functional recovery (rats)
-there is further support from human studies
92
ao3 / strength - there is research to support the claim for functional recovery (rats)
+ however
P - there is research to support the claim for functional recovery
E - taijiri et al. (2013) found that stem cells given to rats after brain injury showed a development of neuron-like cells in the area of injury
↳ this was accompanied by a solid stream of stem cells migrating to the brain’s site of injury
↳ this didn’t happpen in the control group with no transplant of stem cells.
L - this shows the brains ability to create new connections using neurons manufactured by stem cells & shows that the brain can recover after traumatic injury and adds support to the idea of functional recovery
however - animal study so hard to generalise to humans
93
ao3 / strength - there is further support from human studies
(+ however)
P - there is further support from human studies
E - human echolocation is a learned ability for humans to sense their environment from echoes
↳ this ability is used by some blind people to navigate their environment
↳ studies in 2010 and 2011 using fMRI techniques have shown that parts of
the brain associated with visual processing have adapted to process click echoes (rather than them being processed by areas devoted to audition)
L - this provides support for both neuroplasticity and functional recovery of the brain
HOWEVER - in humans evidence is restricted to small scale studies of people who already have issues, it is unclear whether what we are seeing is due to recovery or an individual difference
94
Explain what happens in the brain during functional recovery.
-during functional recovery, the brain is able to rewire and reorganise itself by
forming new neural connections
-this can be done through neuronal unmasking, where ‘dormant’ synapses (ones that have not received enough input to be active) open connections so that
functions can move around an area of damage (to compensate for a damaged area of the brain
-axonal sprouting occurs so that new nerve endings grow and connect with other, undamaged nerve cells to form new neuronal pathways
-sometimes recruitment of homologous (similar) areas can occur so that the
opposite side of the brain can perform specific tasks
95
Chelsea was hit by a car when crossing the road when she was 15 and suffered severe head injuries. While she made a full physical recovery, immediately after the accident she had problems speaking and understanding language. However, after a year she had overcome most of her language problems.
Use your knowledge of plasticity of the brain and functional recovery after trauma to explain Chelsea’s recovery. (4 marks)
-chelsea’s accident must have caused damage to the left hemisphere of her
brain, particularly **Broca’s area** (responsible for language production) and **Wernicke’s area** (responsible for language comprehension)
-since she has recovered these functions after a year, this suggests that
chelsea’s brain must have adapted and formed new pathways (plasticity) by
redistributing or transferring the language functions
-this could have been through neuronal unmasking, where dormant synapses near to the language areas in Chelsea’s brain have opened connections to compensate for the damage to the language centres
-recruitment of homologous or similar areas in the right hemisphere of Chelsea’s brain could have occurred, where the equivalent of Broca’s area and Wernicke’s area have begun to carry out the language
functions
96
Lotta's grandmother suffered a stroke to the left hemisphere, damaging Broca's area and the motor cortex
(a) Using your knowledge of the functions of Broca's area and the motor cortex, describe the problems that Lotta's grandmother is likely to experience.
damage to Broca’s area → broca’s aphasia
↳ it will affect her language production (but not her understanding)
↳ lotta’s grandmother will talk without fluency (slow, laboured and disjointed speech)
damage to the motor cortex
↳ loss of muscle function/fine motor control
↳ motor impairments on the right side of the body
97
what is spatial resolution?
refers to the smallest feature (or
measurement) that a scanner can detect (pixel and clarity of image)
98
why is spatial resolution important?
greater spatial resolution allows psychologists to discriminate between different brain regions with greater accuracy
99
what is temporal resolution?
refers to how quickly the scanner can detect changes in brain activity
100
which techniques do we need to know?
-functional magnetic resonance imaging (fMRI)
-electroencephalogram (EEG)
-event-related potentials (ERPs)
-post-mortem examinations
101
how do fMRI’s work?
-strong magnetic fields and radio waves are used to measure brain activity while a person is performing particular tasks
-when a brain area is more active it consumes more oxygen → an increase in blood flow is a response to the need for more oxygen in that area of the brain when it becomes active
-oxygen is carried in the bloodstream
attached to haemoglobin & is released for use by these active neurons, the haemoglobin becomes deoxygenated
↳ deoxygenated haemoglobin has a different magnetic quality from oxygenated haemoglobin
-an fMRI can detect these different magnetic qualities and creates a dynamic (moving) 3D map of the brain, highlighting which areas are involved in different neural activities.
102
strengths of fMRIs:
-non-invasive
-good spatial resolution
103
strength of fMRIs - non invasive
P - non-invasive
E - unlike other scanning techniques (eg: PETs), fMRI does not use radiation or involve inserting instruments directly into the brain, and is therefore virtually risk-
free
L - this should allow more patients/participants to undertake fMRI scans which could help psychologists to gather
further data on the functioning human brain and therefore develop our understanding of localisation of function
104
strength of fMRIs - good spatial resolution
P - fMRI scans have good spatial resolution
E - fMRI scans have a spatial resolution of approximately 1-2 mm which is significantly greater than the other techniques
↳ consequently, psychologists can determine the activity of different brain regions with greater accuracy when using fMRI
L - more valid
105
criticism of fMRI
-poor temporal resolution
106
criticism of fMRI - poor temporal resolution
P - fMRI scans have poor temporal resolution
E - fMRI scans have a temporal resolution of 1-4 seconds which is worse than other techniques (e.g. EEG/ERP which have a
temporal resolution of 1-10 milliseconds)
L - psychologists are unable to predict with a high degree of accuracy, the onset of brain activity
107
how do EEG’s work?
-measures electrical activity in the brain
-electrodes ate placed on scalp to detect small electrical charges which result from activity in the brain cells
-the electrical changes are tracked over time and produce a graph called an EEG
108
what are the four types of EEG patterns?
alpha waves, beta waves, theta
waves and delta waves
109
what does each EEG pattern have?
two basic properties that psychologists can examine:
**amplitude** (the intensity of the activity)
**frequency** (the speed of activity)
110
what do EEG patterns produce?
two distinctive states:
synchronised and desynchronized patterns
111
what is a synchronised pattern?
a recognised waveform can be detected
112
what is a desynchronised pattern?
where no pattern can be detected
113
what are EEG’s usually used for?
-to diagnose neurological abnormalities
(eg: epilepsy, tumours or sleep disorders)
this is because unusual arrhythmic patterns of activity may indicate these disorders
-used in studies on sleep to show different stages of sleep
114
strengths of EEG’s:
-extremely valuable in the diagnosis of disorders
-records the brain activity in real time
115
strengths of EEG’s - extremely valuable in the diagnosis of disorders
P - EEG’s have been extremely valuable in the diagnosis of disorders
E - for example, conditions like epilepsy can be detected, as the scans show sudden bursts of activity (that have no pattern), which is characteristic of this disorder
↳ furthermore, it has contributed to our understanding of the stages of sleep and our knowledge of ultradian rhythms
L - this implies it is an incredibly useful scanning technique
116
strengths of EEGs - records the brain activity in real time
P - records the brain activity in real time
E - other techniques present an image of the passive brain
↳ this means a researcher can immediately and accurately measure sudden changes to the brain activity without any lags
117
criticism of EEGs:
-they provide very generalised information
118
criticism of EEGs - provide very generalised information
P - provide very generalised information
E - electrical activity is often detected in
several regions of the brain simultaneously
↳ it can be difficult pinpoint the exact area of activity, making it difficult for researchers to draw accurate conclusions
L - ERPs allow us to determine how processing is affected by a specific stimuli
↳this makes ERP use a more experimentally robust method as it can
eliminate extraneous neutral activity
119
how do ERPs work?
-use similar equipment to EEG, electrodes
attached to the scalp.
-the key difference is that a stimulus is
presented to a participant (eg: picture/
sound) and the researcher looks for activity
related to that stimulus
120
what technique must be used for EEGs and what is its aim?
averaging:
to remove all extraneous brain activity from the original EEG and only leave event related potentials - electrical activity triggered. by a specific stimulus
121
how is averaging done?
-because ERPs are difficult to separate from all of the background EEG data, the stimulus is present many times (usually hundreds), and an average response is graphed
-this procedure, reduces any extraneous neural activity
122
what is latency?
the time between the presentation of the stimulus and the response
123
what latency do ERPs have?
ERPs have a very short latency and can be divided into two broad categories
124
which two categories can ERPS be divided into?
**sensory ERPS*+
-waves (responses) that occur within 100 milliseconds following the presentation of a stimulus (they reflect a sensory response to the stimulus)
**cognitive ERPS**
-ERPS that occur after 100 milliseconds are referred to as cognitive ERPS (they demonstrate some information processing)
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strength of ERPs:
-precise
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strength of ERPS - precise
P - ERPs are extremely precise
E - they are so precise that the patient doesn't need to give a behavioural response to the stimuli for activity to be isolated
L - this means behaviour can be monitored covertly making the evidence highly valid and accurate
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criticisms of ERPS:
-it’s difficult to completely standardise the procedures with this technique
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criticism of ERPS - it is difficult to completely standardise the procedures with this technique
P - it’s difficult to completely standardise the procedures with this technique
E - 'background' noise and extraneous material must be eliminated which is difficult to achieve → it is a difficult technique to use
↳ it’s a very time consuming process & takes several trials to be able to average out meaningful data
L - this suggests that there are limitations to how much meaningful data it can produce
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strengths of EEG and ERP:
-both techniques are non-invasive
-both techniques have good temporal resolution
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strength of EEG and ERP - both techniques are non-invasive
P - that both techniques are non-invasive
E - unlike other scanning techniques (eg: PET) these techniques don’t use radiation or involve inserting instruments directly into the brain → therefore they’re virtually risk-free
↳ EEG and ERP are much cheaper techniques in comparison with fMRI scanning and are therefore more readily available
L - this should allow more patients/participants to undertake EEG/ERPs, which could help psychologists to gather further data on the functioning human brain and therefore develop our understanding of
different psychological phenomena, such as sleeping, and different
disorders like Alzheime
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strength of EEG and ERP - both techniques have good temporal resolution
(+ however)
P - an advantage of the techniques is that it has good temporal resolution
E - it takes readings every millisecond, meaning it can record the brain’s activity in
real time as opposed to looking at a passive brain
↳this leads to an accurate measurement of electrical activity when undertaking
a specific task
HOWEVER
it could be argued that EEG/ERP is uncomfortable for the participant,
as electrodes are attached to the scalp
↳ this could result in unrepresentative
readings as the patient’s discomfort may be affecting cognitive responses to
situations
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what are post mortem techniques?
a way of studying the brains of people who showed psychological abnormalities when they were alive
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what is being looked for with post mortem techniques?
-structural abnormalities (areas of damage) that might be different to those in a control individual
(can be compared to a neurotypical brain)
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example of a post mortem examination:
-broca, examined the brain of a man (Tan) who displayed speech problems when he was alive
-it was subsequently discovered that he had a lesion in the area of the brain
important for speech production
↳ this later became known as broca’s area
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how have post-mortem techniques contributed to the understanding of disorders?
for example:
examining the brains of deceased schizophrenic patients found that they all had a higher concentration of dopamine, especially compared with brains of people without schizophrenia, highlighting the importance of such investigations
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strength of post mortem examinations:
they provide a detailed examination
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post mortem examination strengths - they provide a detailed examination
P - they provide a detailed examination of the anatomical structure and neurochemical aspects of the brain that is not possible with other scanning techniques (e.g. EEG, ERP and fMRI)
E - post-mortem examinations can access areas like the hypothalamus and hippocampus, which other scanning techniques cannot,
L - this therefore provide researchers with an insight into these deeper brain regions, which often provide a useful basis for further research
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criticisms of post mortem examinations:
-the issue of causation
-ethical issues
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post mortem examination criticisms
→ the issue of causation
P - a limitations of post-mortem examination is the issue of causation
E - the deficit a patient displays during their lifetime (eg: an inability to speak) may
not be linked to the deficits found in the brain (eg: a damaged Broca’s area)
↳ the deficits could have been the result of another illness, therefore psychologists are unable to conclude that the deficit is caused by the damage found in the brain
E - another issue is that there are many extraneous factors that can affect the conclusions of post-mortem examinations
↳ eg: any medication a person may have been taking, their age, and the time between death and post-mortem examination
L - these are all confounding factors that make the conclusions of such research questionable
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post mortem examination criticisms
→ ethical issues
P - while post-mortem examinations are invasive, this is not an issue because the patient is dead → however, there are ethical issues in relation to informed consent and whether or not a patient provides consent before his/her
death
E - many post-mortem examinations are carried out on patients with severe psychological deficits (eg: HM who
suffered from severe amnesia) who would be unable to provide fully informed consent, and yet a post-mortem examination has been conducted on his brain
L - this raises severe ethical questions surrounding the nature of such
investigations
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what is the difference between an EEG and an ERP?
**EEG**
EEGs measure general activity within the brain by placing electrodes on the
scalp and looking for brain wave pattern
**ERP**
ERPs use the same equipment as an EEG,
but measure small voltage changes in brain activity when a specific stimulus is presented
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what is the difference between an fMRI and an EEG?
**fMRIs**
-strong magnetic fields and radio waves are used to measure brain activity while a person is performing particular tasks.
-when a brain area is more active it consumes more oxygen, so increased blood flow to an area shows it is active
-fMRI scans produce 3D images which are useful for showing which parts of the brain are involved in particular processes (localisation of function)
(fMRIs have a very high spatial resolution of 1 to 2mm, which means they can be highly accurate in showing which area of the brain is active)
**EEGs**
-electrical activity in the brain is measured using electrodes that are placed on the scalp
-the electrodes detect electrical changes that are caused by brain cell activity and typical patterns include alpha,
beta, delta and theta waves
-they are used to investigate the different stages in sleep & also as a diagnostic tool,
(EEGs have very poor spatial resolution,
meaning they are unable to discriminate between brain regions with accuracy)
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what is the difference between an fMRI and a post mortem examination?
**fMRIs**
fMRI scans are non-invasive as they do not involve radiation or cutting into the brain
**post-mortems**
post-mortems are an invasive technique for studying the brain as they involve cutting into it
