Ways Of Studying The Brain

Question 1

How does fMRI (Functional Magnetic Resonance Imaging) work?

Answer 1

• 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 blood flow is directed to the active area to meet this increased demand
• fMRI produces 3D images (activation maps) showing which parts of the brain are involved in a particular mental process

Question 2

fMRI Strengths

Answer 2

• Doesn’t rely on the use of radiation – if administered correctly, it’s virtually risk-free, non-invasive, and straightforward to use
• Provides very high spatial resolution images, depicting detail by the mm, and providing a clear pic of how brain activity is localised

Question 3

fMRI Limitations

Answer 3

• Is expensive compared to other neuroimaging techniques
• Has poor temporal resolution because of a 5-sec time-lag behind the image on screen and the initial firing of neuronal activity – may not truly represent moment-to-moment brain activity

Question 4

How does an EEG (Electroencephalogram) work?

Answer 4

• Measures electrical activity within the brain via electrodes fixed to an individual’s scalp using a skull cap
• The scan recording represents the brainwave patterns generated from the action of thousands of neurons, providing an overall account of brain activity
• Is often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity (no particular rhythm) may indicate neurological abnormalities such as epilepsy or some sleep disorder

Question 5

EEG Strengths

Answer 5

• Useful in studying sleep stages and diagnosing conditions like epilepsy, a disorder characterised by random bursts of activity in the brain that can be easily detected on screen
• Unlike fMRI, EEG tech has extremely high temporal resolution
• Can accurately detect brain activity at a resolution of a millisecond or less – shows real-world usefulness of the technique

Question 6

EEG Limitations

Answer 6

• The generalised nature of the info (that of many thousands of neurons)
• EEG signal is not useful for pinpointing the exact source of neural activity – it doesn’t allow researchers to distinguish between activities originating in different but adjacent locations

Question 7

How do ERPs (Event-related Potentials) work?

Answer 7

• Within EEG data is all the neural responses associated with specific sensory, cognitive, and motor events – as such, researchers have developed a way of isolating these responses
• Using a statistical averaging technique, all extraneous brain activity from EEG recordings are filtered out, leaving only those responses that relate to something specific
• What remains are ERPs – types of brainwave that are triggered by particular events
• Research has revealed many different forms of ERP and how these are linked to cognitive processes such as attention and perception

Question 8

ERP Strengths

Answer 8

• ERPs address some limitations of EEG by bringing more specificity to the measurement of neural processes
• As ERPs are derived from EEG measurements, they have excellent temporal resolution – ERPs are frequently used to measure cognitive functions and deficits are such as the allocation of attentional resources and the maintenance of working memory

Question 9

ERP Limitations

Answer 9

• Lack of standardisation in ERP methodology between different research studies makes it difficult to confirm findings
• In order to establish pure data in ERP studies, background ‘noise’ and extraneous material must be completely eliminated – not always easy to achieve

Question 10

How do post-mortem examinations work?

Answer 10

• Involves the analysis of a person’s brain following their death
• In psychological research, individuals whose brains are subject to a post-mortem examination are likely those who had a rare disorder and had experienced unusual deficits in cognitive processes/behaviour during their lifetime
• Areas of damage within the brain are examined after death as a means of establishing the likely cause of the affliction the person experienced – may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference

Question 11

Post-mortem Examination Strengths

Answer 11

• Evidence was vital in providing a foundation for early understanding of key processes in the brain
  Broca & Wernicke both relied on post-mortem studies in establishing links between language, brain, and behaviour decades before neuroimaging ever became possible
• Were also used to study HM’s brain to identify the areas of damage, which could then be associated with his memory deficits – post-mortems continue to provide useful info

Question 12

Post-mortem Examination Limitations

Answer 12

• Causation is an issue as observed damage to the brain may not be linked to the deficits under review
• They raise ethical issues of consent from individual before death – participants may not be able to provide informed consent (HM who lost his ability to form memories and was not able to provide such consent)
• This challenges the usefulness of post-mortem studies in psychological research