Brain Imaging Techniques

Question 1

What is the function of fMRI?

Answer 1

Brain-scanning technique which measures blood flow in brain when person performs task
Works on premise neurons in brain most active during task use most energy
Creates dynamic 3D map of brain, highlighting which areas involved in different neural activities

Question 2

What is the function of EEGs?

Answer 2

Works on premise info processed in brain as electrical activity in form of action potentials/nerve impulses, transmitted along neurons

EEGs measure this electrical activity through electrodes attached to scalp

Small electrical charges detected by electrodes are graphed over period of time, indicating level of activity in brain

Question 3

What is the function of ERPs?

Answer 3

Use similar equipment to EEGs (electrodes attached to scalp)
Key difference = stimulus presented to participant (i.e. picture & sound) & researcher looks for activity related to stimulus

Question 4

Evaluate fMRI as a brain imaging technique

Answer 4

STRENGTHS:
NON-INVASIVE - Unlike other scanning techniques, e.g. PET, it doesn’t use radiation or insert instruments directly into brain, thus risk-free - Allows more patients to take them, helping psychs get further data on functioning human brain & thus develop understanding of localisation of function

GOOD SPATIAL RESOLUTION - Smallest measurement scanner detects & is important feature of brain scanning techniques - This allows psychs to discriminate between different brain regions with better accuracy (1-2mm) compared to EEG/ERP

LIMITATIONS:
POOR TEMPORAL RESOLUTION - Speed of scanner detecting changes in brain activity (1-4s) worse than EEG/ERP - Psychs unable to predict with high accuracy onset of brain activity

CAUSATION - fMRI scans don’t provide direct measure of neural activity, simply measure changes in blood flow & thus can’t infer causation - While any change in blood flow may indicate activity within certain area, psychs unable to conclude whether brain region associated with particular function

Question 5

Evaluate EEG & ERP as brain imaging techniques

Answer 5

STRENGTHS:
NON-INVASIVE - Unlike other scanning techniques, e.g. PET, it doesn’t use radiation or insert instruments directly into brain, thus risk-free - Allows more patients to take them, helping psychs get further data on functioning human brain & thus develop understanding of different psych phenomena

GOOD TEMPORAL RESOLUTION - Takes readings every millisecond, thus it can record brain’s activity in real time as opposed to looking at passive brain - Leads to accurate measurement of electrical activity when undertaking specific task

LIMITATIONS:
POOR SPATIAL RESOLUTION - Smallest measurement scanner can detect. Greater spatial resolution allows psychs to discriminate between different regions with greater accuracy, EEG/ERP only detect activity in superficial regions of brain - They’re unable to provide info on what’s happening in deeper region of brain.