AQA Psychology: ways of investigating the brain

How does an fMRI work?

• by dissecting a brain from a corpse

• measures electrical activity within the brain via electrodes that are fixed on the scalp, usually using a skull cap.

• by detecting the changes in blood oxygenation and flow that occurs as a result of neural (brain) activity in specific parts of the brain.

• by using a statistical averaging techniques, that filters out extraneous brain activity from the original EEG recording, leaving only the responses that relate to say, the presentation of a specific stimulus or performance of a specific task.

How does an EEG work?

• by dissecting a brain from a corpse

• measures electrical activity within the brain via electrodes that are fixed on the scalp, usually using a skull cap.

• by detecting the changes in blood oxygenation and flow that occurs as a result of neural (brain) activity in specific parts of the brain.

• by using a statistical averaging techniques, that filters out extraneous brain activity from the original EEG recording, leaving only the responses that relate to say, the presentation of a specific stimulus or performance of a specific task.

How does an ERP work?

• by dissecting a brain from a corpse

• measures electrical activity within the brain via electrodes that are fixed on the scalp, usually using a skull cap.

• by detecting the changes in blood oxygenation and flow that occurs as a result of neural (brain) activity in specific parts of the brain.

• by using a statistical averaging techniques, that filters out extraneous brain activity from the original EEG recording, leaving only the responses that relate to say, the presentation of a specific stimulus or performance of a specific task.

What does an fMRI produce?

• a scan recording represents the brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity.

• lots of graphs with wavy lines

• a graph showing a response to a specific stimulus

• 3D images that are activation maps, showing which parts of the brain are using larger amounts of oxygen and are therefore more active.

What does an EEG produce?

• a graph with lots of wavy lines - the scan recording represents the brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity.

• slices of brain to be physically studied

• a graph showing a response to a specific stimulus

• 3D images that are activation maps, showing which parts of the brain are using larger amounts of oxygen and are therefore more active.

Which is not a strength of fMRI?

• fMRIs, unlike PET scans, do not rely on the use of radiation.

• fMRIs are virtually risk-free, non-invasive and straightforward to use.

• it produces images that have a very high spatial resolution, giving detail by the millimetre.

• fMRI technology has extremely high temporal resolution - it can accurately detect brain activity at a resolution of one millisecond.

Which is not a strength of EEG?

• Unlike fMRI, EEG technology has extremely high temporal resolution - it can accurately detect brain activity at a resolution of one millisecond.

• EEGs are important in the diagnosis of conditions such as epilepsy, a disorder characterised by random burst of activity in the brain that can be easily detected.

• EEGs are a way of teasing out and isolating specific neural responses associated with sensory, cognitive, and motor events.

• it has contributed much to our understanding of the stages involved in sleep

What is a post mortem?

• a technique that involves the analysis of a person’s brain following their death.

• a technique for brain surgery

• a way of scanning the brain using radiation

• a way of destroying the frontal lobes through the back of the eye socket

Which is not a strength of ERPs?

• Researchers have been able to identify many different types of ERP and describe the precise role of these in cognitive functioning including parts of working memory.

• In order to establish pure data in ERP studies, background noise and extraneous material must be completely eliminated, which is not always easy to do.

• ERPs bring much more specificity to the measurement of neural processes than could be achieved using raw EEG data.

• As ERPs are derived from EEG measurements, they have excellent temporal resolution, especially when compared to fMRIs.

Which of these is not a weakness of fMRI?

• fMRI is expensive compared to other neuroimaging techniques and can only capture a clear image if the person stays perfectly still.

• fMRI can only measure blood flow in the brain. It cannot home in on the activity of individual neurons and so it can be difficult to tell exactly what kind of brain activity is being represented on the screen.

• Causation is an issue within these investigations. Observed damage to the brain may not be linked to the deficits under review but to some other unrelated trauma or decay.

• It has poor temporal resolution because there is around a 5 second time-lag behind the image on the screen and the firing of the neurons.