Ways Of Studying The Brain

Question 1

AO1 post mortems

Answer 1

• Investigates the brain after death
• If a person has had an affliction in their lifetime, the brain can be acquired and investigated.
• Any damage found allows us to link that part of the brain to a particular function.
This may also involve comparison with a neurotypical (healthy) brain in order to see the extent of the difference

Question 2

AO1 PET scans

Answer 2

• Allows us to see activity in the brain
• Person injected with radioactive glucose
• Scans detect metabolism of substance and shows which parts of the brain are most active (using up energy) over a period of minutes

Question 3

AO1 MRI

Answer 3

• MRI scans allow up to investigate the structure of the brain
• Strong magnetic waves are sent through the body
• This affects hydrogen atoms and they are forced into different positions
• The scanner picks up these signals and the computer turns them into an image

Question 4

FMRI AO1

Answer 4

• FMRI scans allows us to observe and measure the brains function
• This means we can see the areas that are currently active, not only the structure
• Works by detecting blood oxygenation to each area of the brain (more active areas require more oxygen) this is called the BOLD signal (Blood-oxygen level dependant signal)

Question 5

EEGs AO1

Answer 5

• Electrodes are placed on the surface of the skull
• They measure change in electrical activity when a person performs a specified task
• They record activity from groups of neurons in the brain, but it is a crude measurement shown in waves
• The type of weave shown indicate the part of the brain performing the task
• Can also be used to diagnose epilepsy
• Used to diagnose brain death
• Very high temporal resolution but low spatial resolution

Question 6

ERPs AO1

Answer 6

• Ps undergo multiple EEGS and are presented with a specific stimulus multiple times
• The signals are averaged out so extraneous signals diminish and the signal related to the event remains
• By removing the background noise of general brain activity, researchers can see which electrical activity occurred in response to the event

Question 7

Post Mortem strengths

Answer 7

• PM evidence was vital in providing a foundation for early understanding of key processes in the brain
• Both Broca and Wernicke relied on PM studies in establishing links between language, brain and behaviour decades before neuroimaging began
• PM studies improve medical knowledge and help generate hypotheses for further studies

Question 8

Post Mortem weakness

Answer 8

• Causation is an issue with these investigations (cause and effect)
• Observed damage to the resin may not be linked to the deficits under review but to some other unrelated trauma or decay
• PM studies raise ethical issues of consent from the patient before death
• Patients many not be able to provide informed consent, for example in the case of HM who lost his ability to form memories was not able to provide such consent. Nevertheless PM research has been carried out on his brain.

Question 9

FMRI strengths

Answer 9

• High spatial resolution (detailed)
• No radiation and non-invade so fewer risks (still a risk tho)

Question 10

FMRI weaknesses

Answer 10

• Low temporal resolution (approx 5 sec time lag)
• Expensive
• Patient must be completely still, so limited range of stimuli/responses can be measured (can’t look at sleep/ hallucinations) not always possible to replicate some activity in the scanner
• Practical applications

Question 11

EEGs strength

Answer 11

• EEGS are important in the diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of activity in the brain that can be eulogy detected.
• Similarly it has contributed much to our understanding of the stages involved in sleep (easy to sleep in)
• Unlike FMRI, EEG technology has extremely high temporal resolution
• Todays EEG tech can accurately detect brain activity at a resolution of one millisecond

Question 12

EEGs weaknesses

Answer 12

• EEGs tend to produce very generalised information so it is not useful for pinpointing the exact source of neural activity
• EEGs do not allow researchers to distinguish between activity originating in different but adjacent locations of the brain

Question 13

ERPs strengths

Answer 13

• ERPs partly address the limitations of EEG
• ERPs bring much more specifically to the measurement of neural process than could be achieved using Rae EEG data
• As ERPs are derived from EEG measurements, they have excellent temporal resolution, especially when compared to fMRIs
• The excellent temporal resolution of ERPs have led to their widespread use in the measurement of cognitive functions and deficits
• Researchers have been able to identify many different types of ERP and describe the precise role of these in cognitve functioning including parts of working memory

Question 14

ERPs weaknesses

Answer 14

• Critics have pointed to a lack of standardisation in ERP methodology between different research studies, making it difficult to confirm findings
• A further issue is that in order to establish pure data in ERP studies, background noise and extraneous material must be completely eliminated, which is not always easy to do

Question 15

PET meaning

Answer 15

Positron emission tomography

Question 16

EEGs meaning

Answer 16

electroencephalogram

Question 17

ERPs meaning

Answer 17

Event related potentials

Question 18

MRI meaning

Answer 18

Magnetic resonance imaging

Question 19

FMRI meaning

Answer 19

Functional magnetic resonance imaging