Way of Investigating The Brain
fMRI
fMRI, functional magnetic resonance imaging, works by detecting changes in the levels of oxygenated blood in the brain. We assume that an increase in neural activity correlates with the increase in oxygenated blood – haemodynamic response. This technique gives us a 3D image which allows us to investigate localised areas of the brain weather for different conditions or when participants undergo different tasks
Advantages
Disadvantages
fMRI can be a preferable technique to use as it does not use radiation like other scans such as PET and CT scans. It is relatively risk free and invasive. It shows a clear, localised and precise image of the brain.
However, using fMRI can be expensive and requires significant training. Patients also need to stay perfectly still, and this could bring about some anxiety about the procedure. The results also take time to be processed and displayed therefore it has poor temporal resolution. We must also remember that we are assuming that blood flow relates to neural activity and this may not be the case.
EEG
Electroencephalogram, EEG, measures the brain activity via several electrodes attached the patients head. This generates multiple brain wave patterns from the millions of neurones in the brain and gives us an overall view of the brain’s activity. It has proved useful in the diagnosis of epilepsy, sleep disorders and some brain tumours.
Advantages
Disadvantages
EEGs have proved effective in the diagnosis or certain disorders and has aided the advance in the research of sleep science and stages of sleep. The test also has a high temporal resolution meaning the results are almost instantly displayed so we can see exactly was going on at that exact moment in time.
A significant disadvantage of this technique is that it is assessing the activity of the brain as a whole and therefore we cannot distinguish activity in different areas.
ERP
Using the data from an EEG we can isolate the responses using a statistical averaging technique and create an event-related potential. This then allows us to assess patients/participants perform different tasks with more localised results.
Advantages
Disadvantages
This technique is more specific than an EEG and therefore we can use this to understand and investigate different parts of the brain such as when investigating memory and localisation of the brain. This technique also has a high temporal resolution.
However, this technique is more difficult to use due the difficulty in eliminating the “background noise” from the EEG. This method also lacks standardisation which does not allow for a reliable comparison of results with other research and studies.
Post mortem
A post mortem simply involves investigating the brain after death. We can examine the brain for any areas of damage or assess if there is a difference due to brain disorder and a neurotypical brain.
Advantages
Disadvantages
This procedure was used frequently prior to the advances in neuroimaging and allowed for a relatively rudimental understanding of the brain and associated disorders.
However, we must consider the reliability of our results and if there is a correlation or evidence to prove the cause of a disease or disorder. Although patients can consent to give their bodies to medical research after death there are often when we want to investigate brains of individuals who have suffered a brain disorder, such as HM suffering from amnesia, and we must consider are they capable of consenting to this research.