ways of studing the brain

Question 1

what is functional magnetic resonance imaging (fMRI)?

Answer 1

A method used to measure brain activity while a person is performing a task. £MRI detects radio waves from changing magnetic fields. This enables researchers to detect which regions of the brain are rich in oxygen and thus are active.

Question 2

what is electroencephalogram (EEG)?

Answer 2

A record of the tiny electrical impulses produced by the brain’s activity. By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain.

Question 3

what is event-related potentials (ERPs)?

Answer 3

The electrophysiological response of the brain to a specific sensory, cognitive, or motor event can be isolated through statistical analysis of EEG data.

Question 4

what are post-mortimer examinations?

Answer 4

The brain is analysed after death to determine whether certain observed behaviours during the person’s lifetime can be linked to structural abnormalities in the brain.

Question 5

what is the purpose of scanning?

Answer 5

The purpose of scanning in psychological research is often to investigate localisation - to determine which parts of the brain do what.

Question 6

how do fMRI’s work?

Answer 6

it works by detecting the changes in both blood oxygenation and flow that occur as a result of neural (brain) activity in specific parts of the brain.
When a brain area is more active it consumes more oxygen and to meet this increased demand, blood flow is directed to the active area

Question 7

what do fMRI’s produce?

Answer 7

they produce three- dimensional images (activation maps) showing which parts of the brain are involved in a particular mental process and this has important implications for our understanding of localisation of function.

Question 8

how do EEG’s work?

Answer 8

they measure electrical activity within the brain via electrodes that are fixed to an individual’s scalp using a skull cap. The scan recording represents the brainwave patterns that are generated from the action of thousands of neurons, providing an overall account of brain activity.

Question 9

why are EEGs used?

Answer 9

often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity (i.e. no particular rhythm) may indicate neurological abnormalities such as epilepsy, tumours or some sleep disorders.

Question 10

how can you isolate responses from EEGs?

Answer 10

Using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out leaving only those responses that relate to, say, the presentation of a specific stimulus or performance of a specific task.

Question 11

what remains from isolating EEGs

Answer 11

What remains from isolating EEGs are event-related potentials (ERPs) - types of brainwave that are triggered by particular events.
Research has revealed many different forms of ERP and how, for example, these are linked to cognitive processes such as attention and perception.

Question 12

why would an individual have a post-mortem exam?

Answer 12

individuals whose brains are subject to a post-mortem examination are likely to be those who have a rare disorder and have experienced unusual deficits in cognitive processes or behaviour during their lifetime.

Question 13

why are areas examined after death?

Answer 13

Areas of damage within the brain are examined after death as a means of establishing the likely cause of the affliction the person experienced. This may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference.

Question 14

what are strengths of fMRIs?

Answer 14

-unlike other scanning techniques such as PET, it does not rely on the use of radiation. If administered correctly it is virtually risk-free, non-invasive and straightforward to use.
-produces images that have very high spatial resolution, depicting detail by the millimetre, and providing a clear picture of how brain activity is localised.
-This means that fMRI can safely provide a clear picture of brain activity.

Question 15

what are limitations of fMRIs?

Answer 15

-it is expensive compared to other neuroimaging techniques.
-It has poor temporal resolution because there is around a 5-second time- lag behind the image on screen and the initial firing of neuronal activity.
-This means fMRI may not truly represent moment-to-moment brain activity.

Question 16

what are strengths of EEGs?

Answer 16

-its been useful in studying the stages of sleep and in the diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of activity in the brain that can easily be detected on screen. -Unlike fMRI, EEG technology has extremely high temporal resolution.
Today’s EEG technology can accurately detect brain activity at a resolution of a single millisecond.
-This shows the real-world usefulness of the technique.

Question 17

what are limitations of EEGs?

Answer 17

-main lim of EEG is the generalised nature of the information received (that of many thousands of neurons).
-The EEG signal is also not useful for pinpointing the exact source of neural activity.
-Therefore it does not allow researchers to distinguish between activities originating in different but adjacent locations.

Question 18

what are strengths of ERPs?

Answer 18

-they bring much more specificity to the measurement of neural processes than could ever be achieved using raw EEG data.
-they have excellent temporal resolution, especially when compared to neuroimaging techniques such as fMRI. -This means that ERPs are frequently used to measure cognitive functions and deficits such as the allocation of attentional resources and the maintenance of working memory.

Question 19

what are limitations of ERPs?

Answer 19

-lack of standardisation in ERP methodology between different research studies which makes it difficult to confirm findings.
-in order to establish pure data in ERP studies, background ‘noise and extraneous material must be completely eliminated. -This is a problem because it may not always be easy to achieve.

Question 20

what are strengths of post-mortem examinations?

Answer 20

-Post-mortem evidence was vital in providing a foundation for early understanding of key processes in the brain.
-Broca and Wernicke both relied on post-mortem studies in establishing links between language, brain and behaviour decades before neuroimaging ever became a possibility.
-Post-mortem studies were also used to study HM’s brain to identify the areas of damage, which could then be associated with his memory deficits.
-This means post-mortems continue to provide useful information.

Question 21

what are limitations of post-mortem examinations?

Answer 21

-Causation is an issue within these studies.
-Observed damage to the brain may not be linked to the deficits under review but to some other unrelated trauma or decay. -postmortem studies raise ethical issues of consent from the individual before death. -Participants may not be able to provide informed consent, for example in the case of HM who lost his ability to form memories and was not able to provide such consent - nevertheless post-mortem research has been conducted on his brain. -This challenges the usefulness of post-mortem studies in psychological research.