Ways of studying the brain Flashcards
What are the 4 brain research methods?
- Post-mortem examinations
- Functional magnetic resonance imaging (FMRI)
- Electroencephalogram (EEG)
- Event-related potentials (ERP’s)
What is a post-mortem examination?
- Person’s brain examined after death
- Used to see where damage has occurred & explains behaviour of the person before death
- Brain sliced into thin sections & studied microscopically
2 strengths & weaknesses of post-mortem examinations?
- Strengths:
1. Detailed examination of anatomy of brain that is not possible with non-invasive techniques
2. Harrison (2000) suggested structural & neuro-chemical abnormalities linked with schiz were identified using FMRI - Weaknesses:
1. Retrospective method so may be hard to make comparisons with functioning before death
2. When Oxygen cut off from brain, shape & structure changes to findings (like Harrison) may lack accuracy
What is an FMRI?
- Uses strong magnetic & radio waves to monitor blood flow in brain
- Takes repeated scans to create image of concentration of oxygen in blood at any given time
- High activity areas will show high levels of blood flow & oxygenation
2 strengths & weaknesses of FMRI scans?
- Strength
1. Provides moving picture of brain activity vs bland physiology of the brain
2. Non-invasive & does not expose brain to radiation so it is ethical - Weaknesses:
1. Complexity of brain activity means interpreting the scan is ambiguous
2. Focuses on localised activity of the brain so does not account for the brain’s communication with different regions affecting mental functioning
What is an Electroencephalogram (EEG)?
- Electrodes placed on scalp of patient to record brain activity
- Electrodes fitted on a cap & cap put on head with conductive gel
- Electrodes study cells directly beneath them
- Activity picked up is displayed in brain waves
- Amplitude shows brain’s intensity
- Frequency shows speed of activation
2 strengths & weaknesses of EEG?
- Strengths:
1. Cheaper alternative to studying the brain than brain imaging techniques (FMRI)
2. Historically important to understanding the brain (sleep & medical diagnosis) - Weaknesses
1. Expertise is needed to interpret the outcome from the equipment
2. Are not able to detect activity deep in the brain
What is an Event related potential (ERP)?
- Uses same apparatus as EEG’s
- Instead ERP’s record activity in regards to a stimulus
- Stimulus presented many times
- Provides data using statistical averaging
- Waves peaks & dips show when cognitive processes occur when the stimulus is presented
2 strengths & weaknesses of ERP?
- Strengths:
1. Cheaper alternative to studying the brain than brain imaging techniques (FMRI)
2. Historically important to understanding the brain (sleep & medical diagnosis) - Weaknesses:
1. Expertise is needed to interpret the outcome from the equipment
2. Are not able to detect activity deep in the brain
FMRI & EEG comparison?
Similarities:
- Non-invasive & can be done on a live person
- Both deal surface level of brain
Differences:
- FMRI’s deal with blood flow vs EEG deal with electrical impulses
FMRI & ERP comparison?
Similarities:
- Non-invasive & can be done on a live person
- Both deal surface level of brain
Differences:
- FMRI’s deal with blood flow vs EEG deal with electrical impulses
EEG & ERP comparison?
Similarities:
- Non-invasive
- Both use electrical impulses
Differences:
- EEG deals with circadian rhythms (sleep/wake cycle) whereas ERP’s deal with a task
Post mortem & scanning technique comparison?
Similarities:
- All explain abnormal behaviour compared to normal controls
Differences:
- Post-Mortem deals with deceased whereas scans deal with live people
- Post-mortems is the only method to go deep into the brain
