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.
What is meant by temporal resolution?
how closely the measured brain activity corresponds to the timing of the actual neuronal activity.
What is meant by spatial resolution?
the smallest feature (or measurement) that a brain scan can detect.
