ways of studying the brain Flashcards
what are the 4 ways of studying the brain?
post mortems
fMRI
EEG
EPR
what are post mortems?
- post-mortem examinations – brain is examined after death to try and correlate
structural abnormalities/damage to behaviour.
what is an EEG
electrodes are put on the scalp and detect neuronal activity directly below
where they are placed; differing numbers of electrodes can be used depending on
focus of the research
what are fmris
– uses magnetic field and radio waves to monitor blood flow; it measures the
change in the energy released by haemoglobin, reflecting activity of the brain (oxygen consumption) to give a moving picture of the brain; activity in regions of interest can be compared during a base line task and during a specific activity
what are EPRs
– electrodes are put on the scalp and detect neuronal activity (directly below
where they are placed) in response to a stimulus introduced by the researcher
advantage of EEGs
An advantage of the EEG technique is that it has good temporal resolution: it takes readings every millisecond, meaning it can record the brain’s activity in real time as opposed to looking at a passive brain. This leads to an accurate measurement of electrical activity when responding to a specific task.
EEGs and ERPs are cheaper so can be more widely used in research
negative of EEG
poor spatial resolution
it could be argued that EEGs are uncomfortable for the participant as electrodes are attached to the head. This could result in unrepresentative readings as the patient’s discomfort may be affecting cognitive responses to situations. fMRI scans, on the other hand, are not invasive and would not cause the participant any discomfort, leading to more accurate recordings.
what is spatial resolution?
Spatial = where - where the specific functions are occurring
what is temporal resolution?
Temporal = time - whether you are able to see in real time what is occurring in the brain, or whether there is a delay
what are the + of fmri
good spatial resolution
not invasive
fMRI captures dynamic brain activity as opposed to MRI/post-mortem examinations
which purely show physiology
what are the negatives of fMRIs
have to lie perfectly still or the scan must be re done
time consuming
interpretation of fMRI is complex and is affected by temporal resolution, biased
interpretation and by the baseline task used
fMRI research is expensive leading to reduced sample sizes which negatively
impact the validity of the research
what are the strengths of EPRs
1-10ms temporal resolution so practically real time
cheaper so can be more widely used in research
what are the limitations of EPRs
poor spatial resolution
-in order to get pure data in ERP studies, environment needs to be highly controlled (background noise and distractions are eliminated)
what are the strengths of post mortems ?
provides a foundation for early understanding of key processes in the brain
-Broca & Wernicke relied on such techniques
-this was identified decades before the use of neuroimaging was a possibility
what are the weaknesses of post mortems?
post-mortem examinations may lack validity due to small sample sizes (as special permission needs to be granted)
could be neuronal changes during and after death
cause and effect cant be established linking a particular behaviour to damage within a particular area of the brain is problematic as there may be other factors that contribute to it but aren’t accounted for
