Ways of Studying the Brain (OCR A-Level Psychology): Revision Notes
6.3.4 Ways of Studying the Brain
fMRI – (functional Magnetic Resonance Imaging)
fMRI: A brain scanning technique that detects changes in the levels of oxygen in the blood by measuring changes in blood flow that occur across parts of the brain whilst people perform tasks.
This is because areas of the brain that are more active require more oxygenated blood. Therefore, more blood flows towards that brain region to carry oxygen.
This enables psychologists to see which brain areas are active when doing a particular task as deoxygenated and oxygenated haemoglobin have different magnetic qualities, an fMRI scanner can detect these different qualities and use it to create a moving 3D map of the brain.
(1)
P: Has high spatial resolution, meaning it is useful for detecting the exact position of brain activity as it can detect very small measurements of brain regions that are active
E: This is approximately 1-2mm, which is significantly greater than other techniques, such as EEG, which can only detect activity on the cortex of the brain.
E: This is a strength as it allows psychologists to discriminate between different brain regions with greater accuracy, helping to pinpoint specific brain regions that are active during a particular task
(2)
P: A strength is that it is a non-invasive method of studying the brain
E: As a result, researchers are able to relate activity in the brain to behaviour without actually manipulating the brain, such as they do in post-mortem examinations, where the brain is dissected and studied in microscopic detail.
E: This makes it an ethical way of studying the brain in comparison to invasive methods such as post-mortems
3:
P: Poor temporal resolution
EEG (Electroencephalography)
EEG: A technique that measures electrical activity in the brain by placing electrodes on the scalp to pick up electrical activity on the surface of the brain (cortex).
Small electrical charges are detected by the electrodes and graphed over a period of time, indicating the level of activity in the brain. This can be used to detect illnesses such as epilepsy and Alzheimer's
(1)
P: Has good temporal resolution, meaning it is useful in detecting when brain activity takes place
E: This is because EEG scanners take readings every millisecond, meaning it can record brain activity in real-time, as opposed to looking at a passive brain. This is better than other techniques, such as FMRI, which has a temporal resolution of 1-4 seconds.
E: This suggests that EEG can provide a high degree of accuracy when examining when brain activity starts, allowing psychologists to make accurate conclusions about the timing of neural activity, in comparison to FMRI
(2)
P: A strength is that it is a non-invasive method of studying the brain
E: This means that researchers are able to relate activity in the brain to behaviour without actually manipulating the brain
E: This makes it an ethical way of studying the brain
(3)
P: Poor spatial resolution
ERP (Event Related Potentials)
ERP: Small electrical signals recorded using electrodes attached to the scalp, that occur in response to a stimulus over multiple of trials.
- Then, an average response over all trials is graphed, to identify ERPs which can be related back to the stimulus and the behaviour of the participant.
(1)
P: A strength is that it is a non-invasive method of studying the brain
E: This means that researchers are able to relate activity in the brain to behaviour without actually manipulating the brain
E: This makes it an ethical way of studying the brain
(2)
P: The researcher requires a large number of trials to obtain meaningful data
E: This can be time-consuming for the researcher and repetitive for the participant
E: Therefore, it can be considered impractical
Post-mortem examinations
Post-mortem examination: When a person's brain is examined in detail after death to look for evidence of brain abnormalities. The brain is dissected and studied in microscopic detail.
- This can be related back to unusual behaviours they displayed when they were alive.
(1)
P: Post-mortem examinations allow a person's brain to be examined at a very high level of detail
E: This is because the brain is divided into small sections and closely examined under a microscope
E: Therefore, this allows very small brain abnormalities to be identified, such as abnormal synapses
(2)
P: There is no information about when the patient developed brain abnormalities
E: This is because researchers are looking at the patient's brain after death
E: Therefore, making it impossible to establish a solid cause-and-effect relationship between the brain abnormality and abnormal behaviour displayed by the patient while they were alive using post-mortem examinations
(3)
P: It is difficult to control extraneous or confounding variables
E: For instance, a patient taking medication during their life could affect their brain. However, as the patient is no longer alive it makes it difficult to know whether the medication could have caused the brain abnormalities.
E: This makes it even harder to establish a cause-and-effect relationship between the brain abnormality and the abnormal behaviour