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STARTER – Yr12 recap questions
07 Identify the two components of the peripheral nervous system, and explain two differences in their organisation and/or functions. [4 marks]
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STARTER – Yr12 recap questions
Marks for this question: AO1 = 2 and AO3 = 2 One mark each for components of the peripheral nervous system - the somatic nervous system (SNS) and the autonomic nervous system (ANS). Plus One mark each for relevant difference explained. Possible differences the SNS has sensory and motor pathways, while the ANS is purely motor; the ANS controls internal organs and glands of the body while the SNS controls skeletal muscle, movement etc; SNS is involved in voluntary actions and the ANS is involuntary ANS control centres are in the brain stem whilst SNS carries commands from the motor cortex. Credit other relevant differences. There must be explicit focus on ‘differences’ between SNS and ANS for marks to be awarded, rather than independent references to each.
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STARTER – Yr12 recap questions
10 Identify two glands that form part of the endocrinal system and outline their functions. [4 marks]
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STARTER – Yr12 recap questions
One mark each for identification of glands Plus One mark each for description of functions of the glands. This may be in terms of the hormones released and either their regulation of internal organs and processes or an outline of the effects on behaviour. Possible content Pituitary gland releases ACTH. Controls release of hormones from other glands. Adrenal gland and adrenaline/noradrenaline, causing physiological changes associated with arousal, fight and flight. Credit also other glands - pancreas and insulin, ovaries and oestrogen/progesterone, testes and testosterone.
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A LEVEL (Yr2) BIOPSYCHOLOGY (New Content) – Power Point 1
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What the spec says you have to know…
Localisation of brain function and hemispheric lateralisation; motor, somatosensory, visual, auditory and language centres; Broca’s and Wernicke’s areas, split brain research. Plasticity and functional recovery after brain trauma. This is the first of three bullet points for biopsychology
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Localisation & Lateralisation of Brain Function
During the 19th century it was discovered that certain areas of the brain held particular functions. This is known as ‘localisation of brain function’. The brain is divided into two hemispheres: the left and the right. Each hemisphere (side of the brain) is responsible for specific functions Localisation: the theory that specific areas of the brain are associated with particular physical and psychological functions Lateralisation: the dominance of one hemisphere of the brain for particular physical and psychological functions
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The motor, somatosensory, visual and auditory centres
LEARN THIS!!! The motor, somatosensory, visual and auditory centres The cortex of the brain (meaning the grey wrinkly bit on the outside) is subdivided into four ‘lobes’. Each lobe deals with different functions. Problem solving, emotions, reasoning, speaking, voluntary motor function Sensation, processing of pain, body orientation Vision and colour perception Understanding of language, auditory ability and memory acquisition
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Broken Brains The language area of the brain:
Unlike the areas explained previously the language areas of the brain are concentrated in the left hemisphere of the brain. In the 1880’s, a surgeon named Paul Broca identified an area in the left frontal lobe (Broca’s area) that deals with speech production. Damage to this area results in Broca’s aphasia which is characterised by slow speech and also lacks fluency. After watching the clip of Broken Brains, describe the case of Leborgne (‘Tan’) (this can be done on the back page of your booklets), who was nicknamed "Tan" and what the significance of this case is in relation to biopsychology and localisation. broken-brains_school
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Speech So, Broca’s area is responsible for speech then???
No, unfortunately it’s not that simple (it never is is it???) Around the same time Karl Wernicke identified patients that had no problem producing language but severe difficulty understanding it. So the speech they produced was fluent but meaningless. Wernicke identified an area in the left temporal lobe (Wernicke’s area) as being responsible for understanding language which would result in Wernicke’s aphasia when damaged. Patients with this will produce nonsense words (neologisms) as part of the content of their speech.
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Broca’s area or Wernicke’s area?
So, in a nutshell, Broca's area deals with production of language and Wernicke's area deals with comprehension of language. One area of interest (speech), but two different functions and two different areas.
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Evidence for the two areas of speech
Peterson et al. (1988) scanned brains to demonstrate Wernicke’s area being active during a listening task, and Broca’s area active during a reading task. Suggesting these areas of the brain have different functions.
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Further evaluation for localisation of brain function
Tulving et al. (1994) found that semantic and episodic memories are in different parts of the prefrontal cortex. There are now many sophisticated methods of scanning and measuring activity in the brain, which provide sound scientific evidence for localisation. Neurosurgery is still used today for treatment-resistant severe depressives and extreme cases of OCD. The success of these procedures strongly suggests that symptoms and behaviours associated with serious mental disorders are localised Lobotomy: removal of the brain tissue Leucotomy: cutting the connections to a particular part of the brain (electrical stimulation)
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Further evaluation for localisation of brain function
Dougherty et al (2002) found that of a sample of 44 patients with OCD who had received cingulotomy (a procedure which lesions the cingulate gyrus), post-surgical follow ups found that a third of participants had met the criteria for successful response to the surgery, and 14 % had a partial response.
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Further evaluation for localisation of brain function
Case study evidence…. The curious case of Phineas Gage (complete p.5 & p.6 in your booklets)
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Additional points about localisation
Some functions seem to be more localised than others. This may be in some way due to their complexity, e.g. motor function is very obviously localised to the frontal lobe, speech is less localised as is present in several different areas and something like personality or consciousness are yet to be shown as being localised.
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So, back to the spec then…….
Which lobe is responsible for….. Motor function Somatosensory (sensation) visual Auditory speech
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So, back to the spec then…….
Which lobe is responsible for….. Motor function FRONTAL LOBE Somatosensory (sensation) PARIETAL LOBE Visual OCCIPITAL LOBE Auditory TEMPORAL LOBE Speech FRONTAL LOBE/PARIETAL LOBE
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Summary questions Using an example, explain what is meant by the term ‘localisation’ [2 marks] Describe one study in which localisation of brain function was investigated. Include details of what the psychologists did and what was found [3 marks] Name the four lobes of the human brain – for each lobe, give an example of an associated function [4 marks]
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Essay question Discuss the extent to which brain functions are localised. Refer to evidence in your answer . [16 marks] Systematic research from Wernicke and Broca onwards has demonstrated the localised nature of speech. Broca’s area was thought to be responsible for the production of speech and his is now thought to involve a wider network than just Broca’s area. Wernicke’s area seems to be responsible for the interpretation of speech This claim can be supported by Broca’s own research… Other examples of localisation of function….(O.C.D. – cingulate gyrus, memory – hippocampus (H.M.), aggression & impulsivity – Phineas Gage) Supported by research…….. Problems associated with different types of research evidence (don’t just focus one case studies and evaluating them as once you’ve got the mark one you won’t get it again).
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Sperry Explanations of findings
Objects placed in right hand are identified by left hemisphere which controls speech. Objects placed in left hand are identified by right hemisphere which has no speech capacity. Objects can only be retrieved by the same hand because information cannot be passed to the opposite hemisphere as the corpus callosum had been severed. Because split-brain people have had the two hemispheres disconnected so information cannot be passed across/the two hemispheres cannot communicate with each other.
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PLASTICITY AND FUNCTIONAL RECOVERY OF THE BRAIN AFTER TRAUMA
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Brain plasticity The brain would appear to be ‘plastic’ meaning that it has the ability to change throughout life. When we are babies there is a rapid growth in the number of synaptic connections it has, it peaks to around 15,000 at age 2-3 years. This equates to twice as many that are in the adult brain. As we age, rarely used connections are deleted and others are strengthened. Originally it was thought that when we are adults that the changes stop. However recent research suggests that at any time in our lives existing neural connections can change and new ones can be formed, this results from learning new things and also from our experiences (plasticity) Jody Miller – how does this support plasticity?
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Maguire (2000) Read the Maguire article and describe what it found and how that relates to the notion of brain plasticity.
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Maguire (2000) Maguire’s study supports brain plasticity as it shows that the possibility of local plasticity in the structure of the healthy adult human brain, as a function of increased exposure to an environmental stimulus. E.g the taxi driver’s brains had changed due brain plasticity.
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Draganski et al (2006) Magnetic resonance images were obtained at three different time points while medical students learned for their medical examination. During the learning period, the gray matter increased significantly in the posterior and lateral parietal cortex bilaterally. These structural changes did not change significantly toward the third scan during the semester break 3 months after the exam. The posterior hippocampus showed a different pattern over time: the initial increase in gray matter during the learning period was even more pronounced toward the third time point. These results indicate that the acquisition of a great amount of highly abstract information may be related to a particular pattern of structural gray matter changes in particular brain areas.
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Functional recovery of the brain after trauma
Following physical injury, or other forms of trauma such as a stroke, it has been seen that unaffected areas of the brain are able to take over and compensate for the damaged areas. This functional recovery is another example of plasticity. Neuroscientists suggests this can happen quickly after trauma and then slow down, where a person may have to undergo rehabilitation to help further their recovery.
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What happens during recovery?
The brain is able to rewire itself and reorganise by forming new synaptic connections. Secondary neural pathways, that wouldn’t normally carry out those functions are activated to enable functioning to continue, often like before. This is supported by some structural changes on the brain: Axonal sprouting: The growth of new nerve endings which connect with other undamaged nerve cells to form new pathways. Reformation of blood vessels Recruitment of homologous (similar) areas on the opposite side of the brain to perform specific tasks. An example would be if Broca’s area was damaged on the left side of the brain, the right side would then try to carry out its function. After recovery it would then shift back.
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Evaluation of Plasticity & Functional recovery after trauma
Practical Application The field of neurorehabilitation has developed from what we have found out about when looking at plasticity. This is basically when recovery after trauma, after initially seeming spontaneous and significant slows down. At this point therapeutic techniques are introduced such as physical (movement) therapy and electrostimulation which appear to help the brain ‘heal itself’. This therefore can help patients recover quicker after trauma and the contribution of our understanding of this is invaluable to quickly improve quality of life in patients.
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Evaluation of Plasticity & Functional recovery after trauma
Plasticity and Age Most research seems to support the idea that plasticity reduces with age and that the greatest potential for ‘new growth’ and reorganisation comes in childhood. However, that is not to say that it does not happen in later life, it’s just slower and less significant. Bezzola (2012) used fMRI scans to observe changes in the motor cortex of Pps aged who had been given 40 hrs intensive golf tuition (they did not already play the game) and when compared to controls it was seen that motor cortex activity was significantly higher in this group of golf novices! Phrase this point something like, “An issue with the notion of plasticity is that it lessens with age and therefore it’s effects are different for different people…..however, research from Bezzola would suggest that it is still possible in (older) adults….”
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TASKS Using the textbooks…
Complete the 4 mark Q. on Josie’s plasticity and functional recovery (separate sheet of paper) Have a go at the Apply it question on p.40 (research methods and stats), this can be done on p.21/back cover of booklet.
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Exam Question Josie is twelve. Last year she was involved in a serious road accident and suffered head injuries that caused problems with speech and understanding language. Now, a year later, Josie has recovered most of her language abilities. Using your knowledge of plasticity and functional recovery of the brain after trauma, explain Josie’s recovery. [4 marks]
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Exam Question – possible content
When the brain is still maturing recovery from trauma is more likely. As Josie is only 12 this may be a reason for her significant recovery. Recruitment of homologous areas (compensatory mechanisms) – which allows undamaged areas of the brain to take on the function of damaged areas. Growth of new neurons and/or connections to compensate for damaged areas (‘axonal sprouting’ and reformation of blood vessels). Discussion of combination of spontaneous recovery and then neurorehabilitation. You must also be constantly referring to the stem!
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Hemispheric Lateralisation and Split-Brain Studies
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Hemispheric lateralisation and split-brain studies
The cerebrum is made up of the left and right hemispheres, connected by the corpus callosum, which is a collection of nerve tissue containing over 50 million axons. It’s job is to facilitate communication between the two sides of the brain.
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Hemispheric lateralisation and split-brain studies
Split Brain research: A series of studies which have, since the 1960’s been looking at epileptic patients who as part of their treatment have had the two hemispheres of their brains severed. Hemispheric Lateralisation: One hemisphere of the brain being responsible for particular physical and psychological functions
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Hemispheric lateralisation and split-brain studies
As we’ve already seen, language is a function which we can say is subject to hemispheric lateralisation (in this case on the left side). Researchers have been studying this particular idea with great interest since the 1950’s and 60’s and have been trying to identify what other functions could also be lateralised like this. 32 mins into broken brains episode-03-broken-brains_school
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Hemispheric lateralisation and split-brain studies
Roger Sperry studied the functioning of split-brain patients (who had their hemispheres split apart by cutting the corpus callosum), in the 1960s. He was a doctor working in a hospital in California, USA. Also on site were patients who had undergone hemispheric deconnection (split-brain patients) Sperry did not sever the corpus callosum of the epileptic patients himself, he was merely an opportunist! He was able to show that certain functions were housed either fully or mainly in one particular hemisphere He won a Nobel Prize for his work.
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Sperry, R (1968); Hemisphere disconnection and unity in consciousness
The sample was 11 patients who had undergone surgery which severed communication between the two hemispheres of the brain to (apparently) ‘treat’ epilepsy. This essentially meant that the two sides of the brain could not communicate with one another and gave Sperry the perfect opportunity to see the extent to which the two hemispheres worked independently from one another. He compared their functioning to people without epilepsy who had not undergone the procedure. This was a ‘Quasi’ experiment. What does this mean?
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Sperry, R (1968); Hemisphere deconnection and unity in consciousness
Sperry got his Pps to perform different types of tasks to try and identify area of the brain responsible for sight, touch and recognition (amongst other things). In his ‘Describe what you see’ condition, a fairly typical procedure was as follows: This split brain patient is asked to focus on a dot in the centre of the screen. One eye was covered. A single word is flashed up for 1/10 of a second at a time, ‘KEY’ on the left, then ‘RING’ on the right side of the screen.
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Two different words projected, one to each visual field, or composite words
RECAP: Why can the participant SAY ring but only pick up the key?
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Two different words projected, one to each visual field, or composite words
RECAP: Why can the participant SAY ring but only pick up the key? L- KEY – goes to right hemisphere where there is no language centre. Patient reports that they didn’t see anything. If you ask the subject to point to a matching picture or choose an object from a bag, the subject has no problem in doing this. R- RING – can be described as picked up by the left hemisphere which is the language centre
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Describing what you see
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If an object was shown in the left visual field they could DRAW or select what they saw.
If an object was shown in the right visual field they could SAY what they saw.
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Right/left hand object identification
Objects put in he right hand for identification of touch are described or named in speech why is this? Because the Left hemisphere (language) is able to describe the object verbally If objects are placed in the left hand the subject can only make wild guesses and may suggest that nothing was present. Explain this… This is because the language centre is the left hemisphere, so the information from the right hemisphere can’t communicate across both hemispheres.
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Right/left hand object identification
When an object is flashed to the left visual field (right hemisphere) the subject can retrieve the item pictured from a collection of objects using blind touch with the left hand. Subject fails to retrieve the same object with the right hand. Why is this?
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Left Hemisphere Left-hemisphere is equipped with the expressive mechanisms for speech and writing, comprehension and organisation of language. This hemisphere can communicate verbally and in a relatively ‘normal’ manner. It can communicate about the right hand and leg and right half of the body and right visual field
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Right Hemisphere Mute aphasic – can’t express itself verbally
Can express non-verbally, drawing or reaching objects Mental processes that are present centred around the left visual field left hand, left leg and left half of body controlled by this hemisphere.
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Sperry - RECAP Briefly outline Sperry’s procedure in 5 bullet points
Outline Sperry’s main findings in 5 bullet points Summarise what Sperry’s findings tell us about hemispheric lateralisation
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Evaluation of Sperry’s research
Demonstrated lateralised brain functions: this work on split-brain research has allowed us to confidently conclude that the two hemispheres do work differently; left= more analytic and verbal, right= spatial and music. Sperry’s work took place in a highly controlled lab setting. Standardised procedures were used and a strict methodology adhered to which allowed for full replication.
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Evaluation of Sperry’s research
Generalisation issues: did the epilepsy cause changes in the brain? Was it truly because the hemispheres were separated? He used only 11 people- can we generalise from 11? His control group were also made up of 11 people, but who had no history of epilepsy- was this appropriate?
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Evaluation of Sperry’s research
The disconnection between the hemispheres was greater in some patients than others The data was artificially produced as in real life a severed corpus callosum can be compensated for by the unrestricted use of two eyes
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The left hemisphere is sometimes referred to as the ‘analyser’ and the right, the ‘synthesiser’
Language on the left dRawing is on the right
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Applied (AO2) question B.L. is a split brain patient whose corpus callosam was severed surgically to treat her epilepsy. When a picture of a cat is presented to her left field of vision, and a lion to her right she says she saw the lion. However, when asked to pick the picture from a set of picture cards she picks the cat. Explain this using your knowledge of lateralisation of function. (6 marks)
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B.L. sees the cat with her left field of vision as it is presented on her left, and from ther, due to contralateralisation, the information crosses over and is processed by the right visual cortex. Due to the split brain procedure this information is now restricted to the right hemisphere. Due to speech being lateralised on the left hemisphere, in particular Broca’s area, B.L. is unable to say the word ‘cat’. However, B.L. would be able to pick the cat card out of the pack with her left hand as having seen it with her left visual field the info goes to the right hemisphere. Recognition is a right hemispheric function and so this would not be impeded by the inability for the two hemispheres to communicate.
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WAYS OF INVESTIGATING THE BRAIN
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Ways of investigating the brain
We are in a position where our advancement of technology makes it possible to understand the brain (and ultimately our behaviour) in more and more detailed and specific ways. There are several different ways to investigate the brain, each has it’s own way of working and its own strengths and limitations. Your job is to learn and remember all these!!!! Key term: Temporal resolution = refers to the precision of a measurement with respect to time. Spatial resolution = refers to the precision of measurement with respect to actual location of activity (EEG) (EEG vs. fMRI)
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Functional magnetic resonance imaging (fMRI)
Measures changes in brain activity (by monitoring blood flow) while a person performs a task. It measures blood flow in the brain using radio waves and a magnetic field. If a particular area of the brain becomes more active, there is an increased demand for oxygen in that area. The brain responds to this extra demand by increasing blood flow, delivering oxygen in the red blood cells. As a result of these changes in blood flow, researchers are able to produce maps showing which areas of the brain are involved in a particular mental activity.
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Electroencephalogram (EEG)
An EEG measures electrical activity in the brain via electrodes placed on the scalp.EEG data can be used to detect various types of brain disorder (such as epilepsy) or to diagnose other disorders that influence brain activity such as Alzheimer’s disease. When a person is awake but relaxed alpha waves are recorded. When the person is physiologically aroused beta waves. Delta and theta waves occur during sleep. As the person moves from light to deep sleep the occurrence of alpha waves decreases and are replaced first by lower frequency theta waves and then by delta waves.
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Event related potentials (ERPS)
ERPS are a way researchers have devised for ‘teasing out’ and isolating info. from EEGs. All extraneous brain activity from the original EEG is filtered out leaving only the responses that relate to the presentation of a specific stimulus or performance of a specific task. What remains are event related potentials: types of brainwave that are triggered by particular events. Research has revealed many different forms of ERP and how, for example, these are linked to perception or cognition.
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Post-mortem examinations
Investigation of brain tissue after death. Researchers can examine brains to look for abnormalities that might explain pathological behaviour of an individual when they were alive. An early example of this technique was Broca’s work with his patient ‘Tan’, who displayed speech problems when alive and was subsequently found to have a lesion in the area of the brain now known as ‘Broca’s area’; an area important for speech production.
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Strengths & Weaknesses of fMRI
Unlike other scans (such as PET Scans) it doesn’t rely on the use of a radioactive tracer. It’s risk free and non-invasive. It produces high resolution images that are accurate to the millimetre so provides a clear image of where functions are localised. High spatial resolution. Expensive compared to other imaging techniques- requires highly specialised equipment and trained experts. MFRI is an indirect measure of functioning. It is studying blood flow rather than the actual firing of neurones. As such there is a 5 second delay between the neurone firing and activity being detected. This means that what your seeing isn’t quite real time. Low temporal resolution)
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Strengths and weaknesses of EEGs
Has been extremely useful in investigating a wide range of issues including epilepsy and sleep. High temporal resolution (as can detect activity in under one millisecond) A general measure, the signal from an individual neuron is not strong enough to detect so only indicates an areas when many neurons are firing. Low spatial resolution.
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Strengths and weaknesses of event related potentials (ERPS)
More specific than raw EEG readings. Derived from EEG so excellent temporal resolution Differing procedures have been adopted (not standardised so difficult to compare and replicate the findings of studies using this technique) To be successful all extraneous interference needs to be eliminated and this is hard to achieve.
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Strengths and weaknesses of post mortem examinations
Vital during the early days of psychology before technology was developed. E.g Broca and Wernicke Cause and effect is a problem the differences observed can be unrelated to the behaviour. Informed consent- some patients loose the ability to consent during their life time due to the issues that make them of interest to but even those that don’t are problematic because consent is needed from relatives (and needed quickly)
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06 The electroencephalogram (EEG) and event-related potentials (ERPs) both involve recording the electrical activity of the brain. Outline one difference between the EEG and ERPs. (2 marks)
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06 The electroencephalogram (EEG) and event-related potentials (ERPs) both involve recording the electrical activity of the brain. Outline one difference between the EEG and ERPs. (2 marks) 2 marks for clear outline of the key difference: EEG is a recording of general brain activity usually linked to states such as sleep and arousal, whilst ERPs are elicited by specific stimuli presented to the participant. 1 mark for a muddled/vague answer that shows some understanding of general state vs specific response. Note - question is about differences, so no credit for simply describing the technique.
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