Ways of Studying the Brain

• Post-mortem examinations are conducted on the anatomy of the brain, which is studied after death to investigate any possible brain damage.
• fMRI is a brain-scanning technique that measures blood flow in the brain when a person performs a task.
• fMRI works on the premise that neurons in the brain which are the most active (during a task), use the most energy.
• An fMRI creates a dynamic (moving) 3D map of the brain, highlighting which areas are involved in different neural activities.
• An EEG works on the premise that information is processed in the brain as electrical activity in the form of action potentials or nerve impulses, transmitted along neurons.
• EEGs measures electrical activity through electrodes attached to the scalp. Small electrical charges that are detected by the electrodes are graphed over a period of time, indicating the level of activity in the brain.
• ERPs use similar equipment to EEGs (electrodes attached to the scalp), however, they present stimuli to people and the researcher looks for activity related to that stimulus.
• A post-mortem examination is when researchers study the physical brain of a person who displayed a particular behaviour while they were alive that suggested possible brain damage.
• Iverson (1979) examined the brains of deceased schizophrenic patients and found that they all had a higher concentration of dopamine, especially in the limbic system, compared with brains of people without schizophrenia.
• An issue with post-mortem studies is identifying the cause and effect.
• There are many extraneous factors that can affect the results of a post-mortem examination, making reliable conclusions more difficult.
• Medication a person may have been taking, their age, and the length of time between death and post-mortem examination, are all confounding factors that make the conclusions of such research questionable.
• Post-mortem examinations provide a detailed examination of the anatomical structure as well as neurological aspects of the brain, that is not possible with other scanning techniques.
• Post-mortem examinations are ‘invasive’ but this is not an issue because the patient is not alive anymore.
• There can be ethical issues in relation to informed consent and whether or not a patient provides consent before his/her death.
• As deoxygenated haemoglobin has a different magnetic quality from oxygenated haemoglobin, an fMRI scan can detect the difference.
• When haemoglobin is released for use by active neurons, it becomes deoxygenated and can be detected on an fMRI scan.
• fMRI brain scans are non-invasive, which make them more ethical to use with patients.
• fMRI scans have good spatial resolution. This refers to the smallest feature (or measurement) that a scanner can detect.
• fMRI scans have poor temporal resolution. This refers to the accuracy of the scanner in relation of time, or how quickly the scanner can detect changes in brain activity. There is usually a 1-4 second lag behind.
• fMRI scans simply measure changes in blood flow and therefore it is impossible to infer causation.
• There are four types of EEG patterns including alpha waves, beta waves, theta waves and delta waves.
• EEG scans are often used to record sleep patterns in psychological research.
• Synchronised patterns of brain activity are recognised waveforms on an EEG scan.
• An advantage of EEG and ERP scans is that both techniques are non-invasive.
• EEG/ ERPs have poor spatial resolution, making it difficult to detect small changes in activity.
• EEG/ERPs have good temporal resolution as they can take readings every millisecond.
• In an fMRI scan, when the brain is more active, it consumes more oxygen, directing blood flow to the area, showing up on the 3D image on the scan.
• The anatomy of the brain can be studied focusing on structural abnormalities in the brain. Patients with brain damage or mental illness may have their brain compared to typical brains.
• fMRI scans are reliable and objective ways of studying the brain.
• EEGs are useful in clinical diagnosis, for example in detecting epilepsy.
• ERPs are able to pinpoint localisation of function.
• Post-mortem examinations provide detailed anatomical analysis of brain structure that cannot be achieved with other scanning techniques.