Ways of Studying the Brain Flashcards
Medical Techniques
Psychologists use medical techniques to investigate brain localisation.
1) Techniques for investigating the brain are often used for medical purposes in diagnosis of illness.
2) Purpose of scanning in psych research is often to investigate localisation - determine which parts of brain do what.
fMRI
Highlights active areas of the brain.
1) Functioning magnetic resonance in imaging detect changes in both blood oxygenation & blood flow in specific brain areas.
2) When an area is more active it consumes more oxygen & blood flow is directed to the active area.
3) Produces a 3D image showing which parts of brain are active & therefore must be involved in particular mental processes.
Using fMRI with Tasks
1) Study brain activity by getting pps to have their brains scanned while they perform a task using mental processes (e.g. memory & language).
–> Assumption is that brain areas active during the task must be correlated with that mental process.
E.g. Pps spend 1 min solving puzzles then 1 minute resting & continue to alternate between tasks whilst blood flow is observed.
Strengths of fMRI
RISK FREE & HIGH SPATIAL RESOLUTION
1) Unlike other scanning techniques (e.g. PET) fMRI doesn’t rely on use of radiation & is safe.
2) Produces images with high spatial resolution, showing detail by the mm.
–> Means fMRI can safely detect differences in structure and function in different areas of the brain.
Limitations of fMRI
EXPENSIVE & POOR TEMPORAL RESOLUTION & NOT DIRECT MEASURE
1) High running cost compared to other techniques.
2) Has poor temporal resolution:
–> Means fMRI may not truly represent moment-to-moment brain activity// Cannot detect changes in brain activity over time.
3) Not direct measure of neural activity, only the associated blood flow.
EEG
Shows overall electrical activity.
1) Electroencephalogram measures electrical activity within brain via electrodes using a skull cap.
2) Data presents brainwave patterns plotted on a graph - shows overall brain activity.
3) Used a diagnostic tool, e.g. unusual brain wave patterns may indicate abnormalities such as epilepsy, tumours or sleep disorders.
E.g. Epilepsy would show spikes of activity when pp has a seizure.
Strengths of EEG
PRACTICAL USES & HIGH TEMPORAL RESOLUTION
1) Has contributed to our understanding of the stages of sleep.
–> Shows real-world usefulness of the technique.
2) Has high temporal resolution
–> Brain activity in one millisecond// shows brain activity over time well.
Limitations of EEG
POOR SPATIAL RESOLUTION
1) Do not show brain activity of specific areas, only overall brain wave activity.
–> Difficult to know exact source of neural activity.
ERPs
1) Event-related potentials are types of brainwaves that are triggered by particular events.
2) ERP is electrical activity in the brain generated as result of stimuli - EEG is used to study these wave patterns.
4) Can compare normal wave patterns to the patterns that are caused by external stimuli.
Strengths of ERPs
SPECIFICITY & GOOD TEMPORAL RES
1) Measures of neural processes are more specific with ERPs than EEGs.
2) Have excellent temporal resolution
–> better than fMRI.
–> Means ERPs are frequently used in cognitive research.
Limitation of ERPs
LACK OF STANDARDISATION & BACKGROUND ‘NOISE’
1) Lack of standardisation makes it difficult to confirm findings in studies involving ERPs.
2) Background ‘noise’ & extraneous variables must be eliminated.
–> These issues are a problem cause they may not always be easy to achieve.
Post-mortem Examinations
1) Analysis of a brain following a death.
2) Areas of brain are examined to establish the likely cause of a deficit or disorder that the person experienced in life.
3) May also involve comparison with a neurotypical brain in order to assess the extent of differences.
Strengths of Post-Mortems
LOCALISATION & MEDICAL RESEARCH & SPECIFITY
1) Localisation of Brain - Broca & Wernicke localised using post-mortem studies.
2) Increases Medical Knowledge - Used to link HM’s memory deficits to damage in his brain.
3) Post-mortems is an invasive method - means it can access deeper parts of brain & gain more detailed info.
Limitation of Post-Mortems
CAUSATION & ETHICS & CONFOUNDING VARIABLES
1) Observed damage in brain may not be linked to deficits being studied - Confounding variables e.g. age, drug treatments, stage of disease at point of death could affect identification of causation.
2) Raise ethical issues of consent after death (e.g. HM).
