ways of studying the brain

Question 1

functional magnetic resonance imaging

Answer 1

• fMRI detects changes in both blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain
• when a brain area is more active, it consumes more oxygen and then blood flow is directed to the active area (haemodynamic response)
• fMRI produces 3D images (activation maps), showing which parts of the brain are involved in mental processes
• this has important implications for our understanding of localisation of function

Question 2

electroencephalogram

Answer 2

• EEG measures electrical activity within the brain via electrodes that are fixed to the scalp using a skull cap
• scan recording represents brainwave patterns that are generated from neuron activity in terms of amplitude and frequency, providing an overall account of brain activity
• often used by clinicians as a diagnostic tool, as unusual arrhythmic patterns of activity may indicate neurological abnormalities

Question 3

event-related potentials

Answer 3

• EEG is a cruse and very general measure of brain activity
• however, EEG data contains all neural responses associated with sensory, cognitive and motor events that are of interest to cognitive neuroscientists
• researchers have developed ways of isolating these
• using statistical averaging, all extraneous brain activity from original EEG is filtered out, leaves only responses that relate to a specific stimulus or task etc.
• what remains are event-related potentials (ERPs), types of brainwave that are triggered by particular events, average activity happening in brainwaves
• many different forms of ERP, research revealed how these are linked to cognitive processes etc

event - stimulus that is presented to an individual
related - activity related to the event
potential - the neuronal activity created in response to the event

Question 4

post-mortem examinations (autopsy)

Answer 4

• analysis of a person’s brain following their death
• individuals whose brains are subject to post-mortem examinations are likely those with rare disorders and have experienced unusual deficits in cognitive processes or behaviour
• areas of damage in the brain are examined after death as a means of establishing likely causes of affliction
• this may include comparison with a neurotypical brain to ascertain the extent of the difference
• pathologists will weigh brain, measure parts, identify size and discolouration

Question 5

evaluation strength of fMRI

Answer 5

• does not rely on use of radiation
• virtually risk-free, non-invasive and straightforward
• produces images with high spatial resolution, depicting detail by the millimetre
• safely provides a clear picture of brain activity

Question 6

evaluation limitation of fMRI

Answer 6

• expensive compared to other techniques
• poor temporal resolution due to 5 second time lag between screen image and initial firing of neuronal activity
• may not truly represent moment-to-moment brain activity
• not for everyone, kids may be difficult, anybody with claustrophobia or metal in their bodies

Question 7

evaluation strength of EEG

Answer 7

• useful in studying stages of sleep and in diagnosis of conditions such as epilepsy
• has very high temporal resolution (almost instantaneous)
• todays technology can detect brain activity at a resolution of a single millisecond

Question 8

evaluation limitation of EEG

Answer 8

• very general nature of info received
• EEG signal not useful for pinpointing exact source of neural activity, low spatial resolution
• researchers cannot distinguish between activities originating in different but adjacent locations

Question 9

evaluation strength of ERPs

Answer 9

• bring much more specificity to measurement of neural activity than EEGs could
• very good temporal resolution

Question 10

evaluation limitations of ERPs

Answer 10

• lack of standardisation in methodology between research studies, makes it different to confirm findings
• in order to establish pure data, background noise and extraneous variables must be completely eliminated, not always easy to achieve

Question 11

evaluation strength of post-mortem examinations

Answer 11

• vital in providing foundation for early understanding
• Broca and Wermicke relied on these studies to establish links between language, brain and behaviour, decades before neuroimaging was a possibility
• studies also used to study HM’s brain to identify areas of damage, then associated with his memory deficits

Question 12

evaluation limitation of post-mortem examinations

Answer 12

• observed damage may not link with the deficits under review, but maybe to other trauma or decay (can’t establish cause and effect)
• raises ethical issues of consent from the patient before death, may not be able to give informed consent (HM, wouldn’t have remembered giving consent)
• challenges usefulness in psychological research