Ways Of Studying The Brain

Question 1

Why do psychologists use medical techniques?

Answer 1

So they can investigate localisation in the brain- techniques for investigating the brain are often used for medical purposes in the diagnosis of illness but the purpose of scanning in in psychological research is often to investigate localisation of function

Question 2

What are the 4 ways of investigating the brain we need to know?

Answer 2

1- electroencephalogram (EEG)
2- event-related potentials (ERPs)
3- functional magnetic resonance imaging (fMRI)
4- post-mortem examinations

Question 3

What does fMRI do and how does it work?

Answer 3

Detects change in blood deoxygenation and flow that occurs to neural activity in specific brain areas (when a brain active is more active, it consumes more oxygen due to increased cellular activity and blood flow is directed to the active area- haemodynamic response). FMRI produces a 3D image showing which parts of the brain are involved in particular mental processes

Question 4

What do EEGs do and how do they work?

Answer 4

Measures electrical activity within the brain via electrodes using a skull cap. The scan recording represents overall brain activity- the brainwave patterns generated from millions of neurones. There are 4 basic EEG patterns: alpha, beta, delta and theta- when an individual is awake but relaxed, rhythmic alpha waves are recorded, but when an individual is physiologically aroused their EEG pattern shows low amplitude, high frequency beta waves. EEG is often used as a diagnostic tool e.g. unusual arrhythmic patterns of brain activity may indicate abnormalities such as epilepsy, tumours or sleep disorders.

Question 5

Explain event-related potentials

Answer 5

Using a statistical technique, all extraneous brain activity, ‘background noise’, from an EEG recording is filtered out leaving only the responses that respond to say the presentation of a certain stimulus or performance of a certain task; what remains are event-related potentials (types of brainwave that are triggered by particular events). Research has revealed many different forms of ERP, and for example, how these are linked to cognitive processes such as perception and attention

Question 6

Explain post-mortem examinations

Answer 6

A post-mortem examination is a technique involving the analysis of a person’s brain following their death- areas of the brain are examined as a means of establishing the likely cause of a deficit or disorder that an individual suffered in life. This may also involve comparison with a neurotypical brain in order to assess the extent of the difference

Question 7

What’s an example of post-mortem examinations?

Answer 7

An early example of this technique was Broca’s work with his patient Tan who displayed speech problems when alive and was found to have a lesion in the area of the brain that is now known as ‘Broca’s area’, an area predominantly responsible for speech production

Question 8

What are the evaluation points of fMRIs?

Answer 8

✅ non-invasive technique and unlike other scanning techniques such as PET scans, fMRI does not rely on the use of radiation and so is a much safer option for the individual- another strength is that it produces images that have very high spatial resolution, showing detail to the mm = provide a clear picture of how brain activity is localised

❌ expensive compared to other techniques so many not be able to be utilised on a large scale. FMRIs can also only capture a clear image if the person stays completely still. Another limitation is that it has poor temporal resolution because there is around a 5-second time lag behind the image on the screen and initial neural activity= may not truly represent moment-to-moment brain activity

Question 9

What are the evaluation points of EEGs?

Answer 9

✅ proved invaluable in diagnosing conditions such as epilepsy and has also contributed to our understanding of the stages involved in sleep. Another strength is that EEGs have extremely high quality temporal resolution as today’s EEG technology can accurately detect brain activity’s a resolution of a millisecond = causal relationships can be established

❌ generalised nature of the information received (that of tens of thousands of neurones) = EEG signal not useful for pinpointing the exact source of the neural activity = causal relationships cannot be established- another limitation is that it is difficult to know the exact source of neural activity as EEGs do not allow researchers to distinguish between activity coming from different but adjacent locations

Question 10

What are the evaluation points for ERPs?

Answer 10

✅ produce very specific measurements of neural processes, much more specific than could ever be achieved using raw EEG data
- another strength is that, like EEGs, ERPs have excellent temporal resolution especially when compared to other neuroimaging techniques such as fMRI and this has led to their widespread use in the measurement of cognitive functions and deficits. Ultimately, causal relationships can be established between stimuli and localised neural response

❌ lack of standardisation in ERP methodology between different studies; this lack of standardisation makes it difficult to confirm findings in studies involving ERPs. Another limitation is that in order to establish pure data in ERP studies all background noise (extraneous variables) must be completely eliminated which is not always easy to successfully achieve especially if the research is unaware of possible extraneous variables, potentially reducing ERPs internal validity

Question 11

What are the evaluation points for post-mortem examinations?

Answer 11

✅ vital in producing a foundation for early understanding of key processes in the brain An early example of this technique was Broca’s work with his patient Tan who displayed speech problems when alive and was found to have a lesion in the area of the brain that is now known as ‘Broca’s area’, an area predominantly responsible for speech production- another strength is that post-mortem examinations improve medical knowledge whilst helping to generate hypotheses for further study

❌ causation may be an issue- observed damage in the brain might not be linked to the deficits under review but to some other related trauma or decay. Another issue is that post-mortem examinations raise ethical issues of consent from the patient before death. Patients may not be able to provide informed consent, for example in the case of patient HM who lost his ability to form memories and so wasn’t able to provide such consent- nevertheless research has been conducted on his brain raising concerns about the invasive procedure that HM was unable to provide consent for, disregarding BPS’s ethical guidelines