ways of studying the brain

Question 1

What are the 4 types of studying the brain you need to know?

Answer 1

1. post mortem
   2.fMRI
   3.EEG
   4.ERP

Question 1

describe a post mortem

Answer 1

used to understand neurological behaviour
* looking for abnormalities

E.g Broca’s patient tan - speech problems found a lesion area now known as Broca’s area for speech production

Question 2

Strengths of a post mortem

Answer 2

+ High spatial resolution - microscopic detail as able to go to neuronal level not available with other techniques

+ Allows for deeper investigation - hypothalamus / hippocampus

+ played a central role in understanding the origins of schizophrenia / structural abnormalities / changes it NT systems

Question 3

Post mortems limitatioms

Answer 3

• Poor temporal validity - occurs after death so it is correlational between the damage and behaviour in life
• causality ? doesn’t tell us why they died may have been due to wrong drug treatment / other factors
  Doesn’t prove causality of experiences

Question 4

what is a fMRI ?

Answer 4

Uses magnetic field and a computer
* Measures brain activity whilst PPT perfirns a task
* measures bloodflow identifying increased neurological activity as demand for O2 is higher as is being used
* Allows researchers to make maps of what is involved within the brain

Question 5

fMRI strengths

Answer 5

+ non invasive

+ creates detailed spatial images - precisely identidying regions and patterns overtime as ppt completes tasks - seeing how the brain responds

+ no harmful radiation

+ Objective and reliable rather than verbal reports

Question 6

fMRI limitations

Answer 6

• not a direct measurement but just for particular areas (general) therefore not truly quantitative
• Critics argue it overlooks networked nature of the brain by only looking at specific areas and that it is the communication between areas that provides vital information - so it snapshots not informing of how two places communicate in terms of neural pathways
• measures bloodflow but we think in electrical impulses low validity
• Requires ppt to be still so the tasks that can be investigated are limites

Question 7

what is an EEG?

Answer 7

Electrodes placed on the scalp that records the summation of activity o 1,000 neurones near the electrodes

Provides a general measure of brain activity

The electrical signals measured by voltmenter is graphed as waves

• Can be used to detect brain disorders e.g epilepsy Or even slowing of the brain.
• Alpha, beta, delta and theta waves.

Question 8

EEG strengths

Answer 8

+ high temporal resolution - provides a recording of brain activity in real time - improving utility

+ Allowing for a causal explanations to be made

+ quick way of diagnosing abnormal brain activity e.g epileptic seizures + not invasive

Question 9

EEG limitation

Answer 9

• only measures superficial / exterior brain areas so is not able to measure deeper structural activities
• poor spatial as electrodes pick up activity from 1,000 nearby neurones
• electrodes can be implanted on animals but not ethically viables on humans
• if two electrodes are nearby it may get confused to identify where the precise location of activity
  May not be identifying exact source

Question 10

What is an ERP?

Answer 10

Uses electrodes fixed to participants scalp to detect neuronal activity in response to a stimulus introduced by the researcher

Takes dozens of presentaitons to a stimulus to work out where the specific electrical response is

Readings averages to remove ‘noise’ in recordings

Question 11

ERP strengths

Answer 11

+ due to the continuous nature of the processing, it is possible to identify how a manipulation of a stimulus may impact processing.

+ non invasive
+ high temproal validity - miliseconds
+ Used by neuroscientists to study how sensorry and cognition afffects physiological brain activity - as able to isolate and study individual processes (ie.cognition)

+ can be replicated for quantitative data → flexible process

Question 12

ERPs limitation

Answer 12

• Large number of trials required to gather meaningful data - timely
• • poor spatial as electrodes pick up activity from 1,000 nearby neurones
• electrodes can be implanted on animals but not ethically viables on humans
• Threshold of electrical activity picked up, nothing less, ignoring internal neural activity and only detecting changes in cortex

Question 13

Ethics of all 4

Answer 13

FMRis/EEG/ERP - non invasive
post mortem - Highly invasive family consent needed

Question 14

spatial resolution - fmri

Answer 14

very good accurate within 3mm
+ can be used anywhere throughout the brain

Question 15

spatial resolution- EEG

Answer 15

poor electrodes can pick u activity from thousands of cells
- cannot access deep brain

Question 16

spatial resolution- ERP

Answer 16

poor electrodes can pick u activity from thousands of cells
- cannot access deep brain

Question 17

spatial resolution - post mortem

Answer 17

good can easily access the whole brian physically and use other techniques on it

Question 18

Temporal resolution -fMRI

Answer 18

reasonable
- delay of a few seconds so not always able to link behaviour with activity

Question 19

Temporal resolution - EEG

Answer 19

live activity via electrodes are graphed by computer software

Question 20

temporal resolution ERP

Answer 20

live activity via electrodes are graphed by computer software

Question 21

temporal resolution - post mortems

Answer 21

poor may be decade between behaviour and brainscan

Question 22

Sample sizes - fMRI

Answer 22

are expensive and have low temporal resolution leading to low sample sizes reducing validity

Question 23

Sample sizes -EEG / ERP

Answer 23

• cheaper = enable large sample sized which icnreases validity of the data obtained