ways of studying the brain Flashcards
4 ways of studying the brain
- functional magnetic resonance imaging (fMRI)
- electroencephalogram (EEG)
- event related potentials (ERP)
- post-mortem examinations
describe functional magnetic resonance imaging (fMRI)
- detects changes in blood oxygenation & flow which happen due to neural activity in parts of the brain
- brain area more active = consumes more oxygen & to meet demand, more blood flow directed to the active area (haemodynamic response)
- produces three-dimensional images (activation maps)
strengths of functional magnetic resonance imaging (fMRI)
+) doesn’t rely on use of radiation (eg. unlike PET) & it’s basically non-invasive, risk-free & straightforward to use if administered correctly
+) produces images with high spatial resolution = provides clear picture of how brain activity is localised
weaknesses of functional magnetic resonance imaging (fMRI)
-) expensive compared to other neuroimaging techniques
-) poor temporal resolution (5-second time lag between image & initial firing of neuronal activity) = may not truly represent moment-to-moment brain activity
describe electroencephalogram (EEG)
- measures electrical activity within brain via electrodes fixed to scalp by skull cap
- scan recording represents brainwave patterns generated from action of many neurones = provides overall account of brain activity
- often used by clinicians as diagnostic tool = arrhythmic patterns of activity may suggest neurological abnormalities (eg. epilepsy, tumours)
strengths of electroencephalogram (EEG)
+) useful to study sleep stages & diagnosis of conditions (eg. epilepsy)
+) extremely high temporal resolution (resolution of roughly a single millisecond) = shows real-world usefulness
weaknesses of electroencephalogram (EEG)
-) generalised nature of information received
-) EEG signal not useful for pinpointing exact source of neural activity = doesn’t allow researchers to distinguish between activities originating in different but adjacent locations
describe event-related potentials (ERPs)
- EEG data contain all neural responses associated with specific sensory, cognitive & motor events
- statistical averaging technique where all extraneous brain activity from EEG filtered out leaving only certain responses (ERPs)
- ERPs are types of brainwaves triggered by certain events
strengths of event-related potentials (ERPs)
+) more specificity to the measurement of neural processes than using raw EEG data
+) excellent temporal resolution = frequently used to measure cognitive functions/deficits (eg.
maintenance of working memory)
weaknesses of event-related potentials (ERPs)
-) lack of standardisation in ERP methodology between different research studies = difficult to
confirm findings
-) to establish pure data in ERP studies, background ‘noise’ & extraneous material must be
eliminated = not easy to achieve
describe post-mortem examinations
- analysis of person’s brain after death
- likely to be those with rare disorder & experienced unusual deficits in cognitive processes during life
- areas of damage within brain examined to establish the likely cause of the disorder they experienced
- may involve comparison with neurotypical brain
strengths of post-mortem examinations
+) vital in providing early understanding of key processes in the brain (eg. broca & wernicke relied on
post-mortem studies to establish links between language, brain & behaviour prior to neuroimaging,
used for case study of HM to idenfity areas of damage associated with his memory deficits) = provide useful information
weaknesses of post-mortem examinations
-) causation is an issue as observed damage may not be linked to deficits being reviewed but other unrelated trauma/decay
-) raise ethical issues of consent from individual before death (eg. HM couldn’t provide consent as lost his ability to form memories) = challenges usefulness of post-mortem studies
