Ways of studying the brain Flashcards
what are the ways of studying the brain?
- functional magnetic resonance imaging (fMRI)
- electroencephalogram (EEG)
- event-related potentials (ERGs)
- post-mortem examinations
how does fMRI work?
- detecting changes in both the blood oxygenation and flow that occurs as a result of neural 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 (haemodynamic response)
- fMRI produces 3D images (activation maps)
what do activation maps in fMRI show?
which parts of the brain are involved in a particular mental process and this has important implications for our understanding of localisation of function
how does electroencephalograms work?
- measures the electrical activity within the brain via electrodes that are fixed to an individual’s scalp using a skull cap
- scan recording represents the brainwave pattern that is generated from the action of thousands of neurons, providing an overall account of brain activity
who is EEG often used by?
clinicians as a diagnostic tool as unusual arrhthmic patterns of activity may indicate neurological abnormalities such as epilepsy, tumours or some sleep disorders
how does event-related potentials work?
- data contains all the neural responses associated with specific sensory, cognitive and motor events, which may interest cognitive neuroscientists
- researchers developed a way to tease out and isolate these responses that relate to for example the presentation of a specific stimulus or performance of a specific task
what are ERPs?
types of brainwaves that are triggered by particular events
- many different forms of ERP, linked to cognitive processes such as attention and perception
how does post-mortem examinations work?
- involves the analysis of a person’s brain following their death
- they are likely to have had a rare disorder and have experienced unusual deficits in cognitive processes or 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 involve comparison with a neurotypical brain in order to asceretain the extent of the difference
what are strengths of fMRIs?
- unlike PET scans, it does not rely on the use of radiation
- if administered correctly it is virtually risk-free, non-invasive and straightforward to use
- has very high spatial resolution, depicting detail by the millimetre, providing a clear picture of how brain activity is localised
what are limitations of fMRI?
- expensive compared to other neuroimaging techniques
- poor temporal resolution ( 5s lag behind image on screen and initial firing of neuronal activity
what are strengths of the EEG?
- useful in studying the stages of sleep and in the diagnosis of conditions such as epilepsy(characterised by random bursts of activity) which can easily be detected on screen
- extremely high temporal resolution
what are limitations of studying the brain?
- not useful for pinpointing the exact source of neural activity
- doesn’t allow researchers to distinguish between activities originating in different adjacent locations
what are strengths of event-related potentials?
- much more specificity to the measurement of neural processes
- excellent temporal resolution
- used to measure cognitive functions and deficits (e.g. allocation of attentional resources
what are limitations of event-related potentials?
- lack of standardistaion
- to establish pure data in ERP, background noise and extraneous material must be completely eliminated = may not be easy to achieve
what are strengths of post-mortem examinations?
- provides a foundation for early understanding of key processes in the brain
