Ways of studying the brain

Question 1

What are the research methods that study the brain?

Answer 1

• post mortem
• fMRIs
• EEGs
• ERPs

Question 2

describe what post mortem examinations are?

Answer 2

• has been used to further understanding of the brain for centuries
• before x-ray and MRI it was the one of the few ways to study the relation between behaviour and the brain
• used for examination of structural damage to the brain to establish how/ what damage lead to specific deficits and behaviours observed pre-death

Question 3

what are the strengths of post mortems?

Answer 3

• vital before neuroimaging became possible = Harrison (2000) suggested that the methods was instrumental in helping to understand schizophrenia. suggested that the structural + neurochemical abnormalities linked schizophrenia were identified using this method
• allows exploration of deeper areas within the brain which scan may not be able to reach = detailed examinations of anatomical aspects of brain that is not possible thru non-invasive techniques. researchers exmine deeper regions accurately and potential links o behaviour

Question 4

what are the weaknesses of post mortems?

Answer 4

• difficult to establish causation of function = issues with compariosn of functioning before death as method is retrospective. may not tell us enough about how person functioned before death like their lifestyle. means that researchers cannot follow up potential abnormalities and cognitive functioning as it is too late
• there are factors that can effect the quality and variety of data = after death brain undergoes significant changes meaning findings may lack accuracy, especially if time delay before analysis. as soon as oxygen is cut off from brain the shape and structure of parts alter

Question 5

Describe what functional magnetic resonance imaging (fMRI) is?

Answer 5

• a non-invasive method that uses strong magnetic and radio waves to monitor blood flow in brain.
• takes repeated scans - one a second - to create an image of concerntration of oxygen in blood at any given time.
• areas of high activity will show coresspondingly high levels of blood oxygenation and blood floe which allows sections that are particularly active during diff tasks to be identified

Question 6

what are the weaknesses of fMRIs?

Answer 6

• has poor temporal resolution = has time lag of 5 seconds and the complexity of the brain activity means interpretating the scan is complex and problematic. difficult task made more difficult by time delay of scan.
• it only measures blood flow and not neuronal activity so may be too localised = overlooks networked nature of the brain as focuses only on localised activity of brain. some suggests that it is the communication between diff regions that is most critical to mental functioning and this scanner cannot deduce this.

Question 7

what are the strengths of fMRIs?

Answer 7

• high quality images = provides maving picture of brain activity than just bland physiology of brain. the dynamic structure of brain is highly valuable when trying to link brain to key behaviours.
• high spatial resolution = has spatial resolution of 1-2mm meaning psychologists can discriminate between different brain regions with accuracy.
• risk free and non-invasive = it is a non-invasive method nor does it expose the brain to potential harmful radiation, so it is ethical

Question 8

Describe what electroencephalograms (EEGs) are?

Answer 8

• a non-invasive measurement of electrical activity in the brain, recording of brain activity
• small sensors are attached to the scalp to pick up electrical signals produced when brain cells send messages to each other
• The EEG test measures the size and frequency of the electrical activity associated with certain states like sleep.
• means it can help identify abnormalities in any of these areas and can help detect and investigate epilepsy.

Question 9

what are the strengths of EEG?

Answer 9

• high temporal resolution and is cheap = EEgs are cheaper tha many other methods of studying the brain Hence due to this they are more available and used more extensively. they have no lag time too as an EEg takes readings every millisecond meaning it can establish brain activity in real time
• it has been invaluable to diagnosing conditions like epilespsy and understanding sleep = used effectively in clinical practice to study sleep disorders and epilepsy, for instance, with epileptic seizures, disturbed brain activty is shown and detected with this method and can diagnose epilepsy

Question 10

what are the weaknesses of EEGs?

Answer 10

• difficult to use = output from machines needs to be interpreted. hence there is still a high level of expert required to use this method effectively.
• produces very generalised information on brain activity in localised areas = electrical activity is only recorded at the locations of electrodes, doesnt show connectivity. activity can also be picked up by several neighbouring electrodes therefore the signal is not useful pinpointing the exact source of activity. EEG is only useful for showing general activity levels

Question 11

Describe what event related potentials (ERPs) are?

Answer 11

• use a similar array of recording electrodes as an EEG but it measures electrical activity in response to certain stimulus.
• in order to identify small specific responses, it is necessary to take recording from numerous presentations and then average out the responses to obtain an action potential.
• ERPs are of ten used when investigating fast responses that might not be detected by other techniques.

Question 12

what are the strengths of ERPS?

Answer 12

• it measures specific activity in the brain relating to a specific task = it can directly measure neuronal activity and give the earliest indication of conscious cognitive processing. this is because it can detect the slightest changes due to any environmental manipulation of stimuli.
• only looks at consistent brain activity = useful to measure the reliability of self-reported techniques, especially when the topic of being investigated is sensitive and likely to be affected by social desirability bias like drug misuse.
• has high temporal resolution = same as EEG explanation

Question 13

what are the weaknesses of EPRs?

Answer 13

• poor spatial resolution = it can only detect strong voltage changes across the scalp and in superficial regions of the brain. important electrical activity deep in the brain are not recorded, hence this method is limited to just the neocortex
• difficult to use = same as EEG
• prodces very generalised info brain activity in localised areas = same as EEG