Ways of Investigating The Brain Flashcards
What are the different ways of studying the brain?
Postmortem
EEG
ERP
FMRI
What is meant by a postmortem?
Researchers study the physical brain of a person who displayed a particular behaviour when they were alive.
Looks for correlations between deceased person’s past behaviour and brain.
What are the strengths of a postmortem?
-Deeper regions of brain can be studied e.g hippocampus and hypothalamus.
-Temporal resolution and invasiveness are irrelevant as person is dead.
What are the limitations of a postmortem?
-Must be done within 3 days, may be impractical.
What is meant by an electroencephalogram (EEG)
Used to measure electrical activity in the brain via electrodes attached to the scalp.
Electrodes detect small electrical charges.
5 EEG patterns: Gamma, Alpha, Beta, Theta and Delta.
-Each pattern indicates a different level of activity in the brain.
What are the strengths of EEG?
-Takes 20-40 mins.
-Non-invasive - No radiation used.
-Good temporal resolution - 1-10 milliseconds
What are the limitations of EEG?
-Poor spatial resolution.
What is meant by Event Realated Potentials (ERP)?
Uses similar equipment to EEG however, participant is presented with a stimulus and activity in the brain relating to this stimulus is searched for.
In ERP, what is meant by the cognitive phase and the sensory phase?
Cognitive phase - after 100 ms.
Sensory phase -before 100 ms.
What are the strengths of ERP?
-Excellent temporal resolution, can record brain activity in real time.
-Non-invasive.
What are the limitations of ERP?
-Poor spatial resolution.
-Lack of standardisation in ERP between different studies.
-Extraneous variables must be eliminated in order to establish pure data.
What is meant by Functional Magnetic Resonance Imaging (FMRI)?
Measures brain activity when a person does a task.
Detects changes in blood oxygenation and flow when a person performs a task.
In FMRI, what is meant by a haemodynamic response?
When an area is more active, blood flow is directed to this area.
What are the strengths of FMRI?
-Produces 3-dimensional images, we can see which parts of the brain are involved in particular mental processes - important implication for understanding localisation of function.
-Non-invasive, doesn’t use radiation.
-Good spatial resolution, 1-2mm.
-Most accurate method.
What are the limitations of FMRI?
-Very poor temporal resolution - 5 second time lag.
-Can be very loud, uncomfortable.
