Biopsych: Ways Of Studying The Brain

Question 1

What is a Functional Magnetic Resonance Imaging (fMRI)?

Answer 1

Works by detecting the changes in blood oxygenation and flow that occurs as a result of neural (brain) activity in specific parts of the brain.
- it measures brain activity while a person performs a particular task
- if a particular brain region is more active, theres an increased demand for oxygen, causing increase in blood flow
- produces 3D images that are activation maps, showing which parts of the brain are using larger amount of oxygen —> more active

Question 2

What are some strengths of fMRI?

Answer 2

+ do not rely on the use of radiation (unlike PET scans)
+ Virtually risk-free, non-invasive and straightforward to use
+ images have very high spatial resolution, giving details by the mm.

Question 3

What are some weaknesses to the fMRI?

Answer 3

• expensive and only captured a clear image if the person stays perfectly still
• poor temporal resolution (around a 5 second time lag behind the image on the screen and the firing of neurons)
• only measures blood flow, not individual neuron activity - so difficult to tell exactly what kind of brain activity is being represented.

Question 4

What is an Electroencephalogram (EEG)?

Answer 4

• a technique which measures electrical activity in the brain. Typical activity patterns include alpha, beta, delta and theta waves
• uses electrodes that are placed on the scalp (skull cap) to detect electrical changes that are caused by brain cell activity
• often used by clinicians as a diagnostic tool - as unusual patterns of activity may indicate neurological abnormalities (e.g. epilepsy, tumours or disorders of sleep)

Question 5

What’s some strengths of the EEG?

Answer 5

+ helps for diagnosis of conditions
+ contributed to understanding the stages involved in sleep
+ extremely high temporal resolution (of 1 millisecond)

Question 6

What are some limitations of EEGs?

Answer 6

• produce very generalised info, so not useful for pinpointing exact sources of neural activity
• don’t allow researchers to distinguish between activity originating in different but adjacent locations of the brain

Question 7

What are Event-Related Potentials (ERPs)?

Answer 7

• a way of teasing out and isolating specific neural responses associated with sensory, cognitive and motor events - of interest to cognitive neuroscientists
• work by using statistical averaging techniques, that filters out extraneous brain activity from the original EEG recording, leaving only the responses that relate to the presentation of a specific stimulus or performance of a specific task.
• uses EEG to measure small voltage changes to specific events or stimuli
• types of brainwave that are triggered by particular events
• waves which occur within 100ms are termed sensory, waves which occur after this are termed cognitive.

Question 8

What are some strengths of ERPs?

Answer 8

+ partly address the limitations of EEG- bring much more specificity to the measurements
+ excellent temporal resolution - led to widespread use i the measurements of cognitive functions and deficits

Question 9

What are some limitations of ERPs?

Answer 9

• lack of standardisation in ERP methodology - difficult to confirm findings
• extraneous variables must be completely eliminated (e.g. background noise)- which is hard

Question 10

What is a post mortem examination?

Answer 10

• analysis of the brain when a person dies - the brains are likely those who had a rare disorder and experiences unusual deficits in mental processes or behaviour in their life
• enables researchers to perform a more detailed examination of the anatomical structure of the brain - the deeper regions like the hippocampus
• areas of damage in the brain are examined to establish the likely cause of suffering
• may also involve the comparison with a neurotypical (healthy) brain

Question 11

What are the strengths of post mortems?

Answer 11

+ vital in early understanding of key processes if the brain
+ both Broca’s and Wernicke used these to establish links between language, brain and behaviour decades before neuroimaging began
+ improve medical knowledge and help generate hypotheses for further studies

Question 12

What are some of the weaknesses of post mortems?

Answer 12

• causation is an issue
• observed damage may not be linked to the deficits under review, but other trauma/decay
• ethical issues - need to get patients consent before death, as they can’t provided informed consent otherwise