fMRI Scans show brain activity:

Functional magnetic resonance imaging (fMRI) scans are 3D scans providing structural and functional; information. They show changes in brain activity as they actually happen, by using a really strong magnetic field and radio waves:

1. More oxygenated blood flows to active areas of the brain (to supply the neurons with oxygen and glucose)

2. Molecules in oxygenated blood respond differently to a magnetic field than those in deoxygenated blood

3. So the more active of the brain can be identified on an fMRI scan

Uses of fMRI:

1. fMRI scans are used to research the function of the brain as well as its structure. If a participant carries out a task whilst in the scanner, the part of the brain that’s involved with the function will be more active. (It’s often coloured by the computer so that it shows up more easily.)

2. For example, a participant might be asked to move their left hand when in the fMRI scanner. The areas of the brain involved in moving the hand will show up on the fMRI scan

3. fMRI scans can be used to diagnose medical problems because they can also show damaged or diseased areas of the brain

4. They are also used to study abnormal activity in the brain. For example, Shegrill et al (2001) used fMRI to show which areas of the brain were active during hallucinations in a patient with schizophrenia

fMRI scans are a really useful tool for biopsychologists, as they provide a non-invasive way of studying the brain. However, the machines are very expensive to buy and run. They also require people to lie very still in an enclosed space for a period of time, which can be a problem for people who suffer from claustrophobia (fear of confined spaces). They have poor temporal resolution- this means they don’t show changes over time accurately.

EEGs show electrical activity:

1. An electroencephalogram (EEG) shows the overall electrical activity of the brain. It picks up the signal of many neurons firing together- not individual neurons

2. Multiple electrodes are placed on the scalp and the electrical activity in the brain is recorded for a period of time

3. This produces a pattern of waves. These patterns represent different levels of arousal or consciousness. for example, the different stages of sleep each have their own typical wave patterns

Uses of EEGs:

1. EEGs are commonly used in sleep studies

2. They have also been used in the study of conditions such as depression and schizophrenia. E.g a meta-analysis by Boutros et al (2008) showed that patients suffering from schizophrenia displayed abnormal EEG wave patterns compared to controls

3. Abnormal EEGs have also been identified in patients suffering from eating disorders such as anorexia nervosa

4. This means EEGs have the potential to be used as a diagnostic tool

EEGs and ERPs are also non-invasive, and they are cheaper to carry out than fMRI scans. Although they have a good temporal resolution, they have poor spatial resolution- this means it’s hard to work out which area of the brain the waves originate from

ERPs show electrical activity in the brain in response to a stimulus

1. Biopsychologists can also look at how an EEG wave pattern changes in response to a stimulus

2. This change is known as an event-related potential (ERP)

3. If a specific stimulus is presented, it produces a specific change in the wave pattern

4. Biopsychologists have identified different ERPs which are produced in response to different stimuli

Uses of ERPs:

1. ERPs have been used a lot in memory research, they give biopsychologists lots of clues about information processing in the brain

2. Research has shown differences in the ERPs of people suffering from certain psychiatric disorders compared to healthy individuals. For example, Milner et al (2000) found that people with phobias had an ERP of greater amplitude in response to images of the objects they feared, compared to non-phobic individuals

Post-mortem examinations show the structure of the brain:

1. Post-mortem examinations involve dissecting the brain of a person who has died

2. This allows researchers to physically look at the internal structure of the brain

Uses of post-mortem examinations:

1. If a person had a medical condition when they were alive, a post-mortem could show any structural abnormalities that could explain their condition. For example, a study by Brown et al (1986), which used post-mortem examinations, showed that patients who had suffered from schizophrenia had enlarged ventricles in their brains

2. Post-mortems have provided evidence for localisation of function in the brain. For example, Paul Broca carried out post-mortem examinations on two patients who developed speech problems as a result of brain damage. Both patients had damage to the same area of the brain, so Broca concluded this area (which we know as Broca’s area) was involved in speech production

An obvious disadvantage of post-mortem examinations is that the person has to have died before the examination can be carried out, so they will not benefit from the findings

A disadvantage of all these methods of studying the brain is that although they do give us information about what’s going on in the brain, they don’t allow cause and effect to be established. For example, the enlarged ventricles in people with schizophrenia haven’t necessarily been caused by schizophrenia