Methods of investigating the brain

Created by

Iris Scotford

Cards (8)

Post Mortem Examination  
-is a direct study of an inactive brain after death.
-Involves the use of neural-correlation. Brain structures and areas in neuroatypical (abnormal) brain correlated with structures in neurotypical (normal) brain.
-Inference is made that any structural or biochemical difference between two brains is the area of the brain that is responsible for the cognitive processes or behaviour.
Post Mortem examination evaluation
+Direct study of the brain anatomy unlike FMRI and MRI which can only provide images of the brain.
+Allows for in-depth study and understanding of deeper brain regions.
-small sample size as special consent is needed, issues with generalisation arise to the wider population.
-Studying the brain when inactive provides limited knowledge and process of death and preparing the brain may affect the structures.
FMRI - functional magnetic resonance imaging
-non invasive and indirect way of studying the brain oxygenation and not electrical activity.
-a baseline brain activity is recorded at state of rest. PP performs cognitive/behavioural task using FMRI machine.
-When neurons are activated, demand more oxygen, which is carried by the bloodstream which is detected by FMRI machine.
-Produce moving images of the brain.
-Brain images are compared to baseline when completing tasks.
FMRI evaluation  
+High spatial resolution: can accurately discriminate between areas of the brain. This contributes to localisation of function and plasticity research.
+Non-invasive unlike PET scans. There's less risk involved and increases sample size which increases generalisability of findings.
+Studies brain in it's active state.
-Poor temporal resolution, delay of up to 4 seconds from the onset activity time so issues with determining onset of activity.
-Expensive equipment which means small sample size is probably used.
-Indirect method of studying the brain activity.
EEG - electroencephalography  
-direct measure of the brain activity.
-Cap is placed on the individuals head, electrodes are connected to scalp at specific sites.
-The electrodes record general activity in form of action potential in the brain under where they are placed.
-Small electrical changes detected by electrode and graphed.
-Each e=wave on graph is what each electrode detects.
-Used to analyse brain activity is rhythmic and diagnose arrhythmic patterns like epilepsy and sleep disorders.
EEG evaluation  
+high temporal resolution: accurately detects onset brain activity.
+Relatively cheap equipment and more accessible so a bigger sample size can be gathered.
+Detects actual brain activity so is a direct measure of neural activity.
-Low spatial resolution: electrodes have difficulty discriminating where the brain activity is taking place and at what depth. Poor at researching activity in deeper regions compared to post-Morton.
-Low levels od brain activity may not be registered, large number of neurons needs to be generated to be detected by the electrodes.
ERP'S - event related potentials
-Similar to EEG as that measures electrical activity of the brain directly using electrodes placed in specific regions of the scalp.
-there are electrical signals hidden in EEG data that respond to certain events in the environment.
-Uses statistical averaging techniques to isolate brain activity related to certain stimuli that has been introduced.
-involves synthesising results from EEG and removing extraneous brain activity.
-Shows only electrical activity is a response to introducing specific stimuli.
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ERP'S evaluation  
+ERP'S are more experimentally robust and can eliminate extraneous neural activity.
+Cheaper technology and non-invasive so a larger sample meaning it's more representative.
+High temporal resolution: reading every millisecond, meaning it can record the brain's activity in real time as it responds to a stimuli.
-Poor spatial resolution: can only detect the activity in superficial regions and can't provide information in deeper regions of the brain.