Ways of investigating the brain

• fMRI (Functional Magnetic Resonance Imaging) - Works by detecting the changes in oxygenated blood flow in the brain as a result of neural activity in specific parts of the brain. When a brain area is more active, it consumes more oxygen to meet increased demand. This is known as the haemodynamic response. fMRI's produce a 3D image showing which aspects of the brain are involved in particular mental processes which has important implications for our understanding of localisation of function.
• Electroencephalogram (EEG) - Measures electrical activity of the brain via electrodes which are fixed to an individuals scalp using a skull cap. It is often used as a diagnostic tool as unusual arrythmic patterns can indicate a brain disorder such as epilepsy (characterised by bursts of brain activity), tumours or sleep disorders.
• Event-related potentials - Event-related potentials use electrodes to measure very small voltage changes within the brain when patients are presented with a stimulus such as a picture or sound which requires cognitive processing. Because EEG's in their raw form can be crude and overgeneralise measures of brain activity, event related potentials (ERPs) are used to identify specific brain areas that are activated in response to specific stimuli as neural responses are associated with sensory, cognitive and motor events.
• Post-mortem examinations - Is a technique involving the analysis of a persons brain following their death. Those who are subject to a post-mortem examination are likely to have has a rare disorder and experience unusual deficits in cognitive processing. It aims to find the likely cause of the affliction a person experienced. This may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference.
• The main advantage of brain imaging techniques is they allow researchers to investigate the relationship between behaviour and brain structure/function without having to open up people’s heads!
• One limitation of brain imaging techniques is that they only show correlations between brain activity and behaviour – not causation.