biopsych - ways of investigating the brain - y13 Flashcards
what is functional magnetic resonance imaging (fMRI) ?
-a method used to measure brain activity while a person is performing a task.
-fMRI detects radio waves from changing magnetic fields.
-this enables researchers to detect which regions of the brain are rich in oxygen and thus are active (haemodynamic response)
what is an electroencephalogram? (eeg)
-a record of tiny electrical impulses produced by the brains activity.
-by measuring characteristic wave patterns
-the EEG can help diagnose certain conditions of the brain such as epilepsy.
-electrodes fixed onto someones scalp
-records thousands of neurons firing.
what are event-related potentials? (ERP’s)
-The electrophysiological response of the brain to a specific sensory, cognitive, or motor event can be isolated through statistical analysis of EEG data.
what are post-mortem examinations?
the brain is analysed after death to determine whether certain observed behaviours during the persons lifetime can be linked to structural abnormalities in the brain.
which ways of measuring the brain have high temporal resolution but low spatial resolution?
EEG’s and ERP’S
which ways of measuring the brain have high spatial resolution but low temporal resolution?
fMRI’s and post-mortem examinations.
what are the strengths of fMRI’s?
-unlike other scanning techniques such as PET scans, they do not rely on the use of radiation.
-meaning it is virtually risk-free and non-invasive.
-therefore, fMRI can safely provide a clear picture of brain activity
what are the limitations of fMRI’s?
-expensive compared to other neuroimaging techniques
-poor temporal resolution as it has a 5 second time-lag.
-meaning that fMRI may not truly represent moment-to-moment brain activity.
what are the strengths of electroencephalograms?
-useful in studying the stages of sleep
-extremely high temporal resolution
-useful in the diagnosis of conditions such as epilepsy, meaning it has real world usefulness.
-non-invasive
what are the limitations of electroencephalograms?
-the main drawback of EEGs lies in the generalised nature of the information received - thousands of neurons, making it difficult to pinpoint which part of the brain it had come from.
-therefore, it does not allow researchers to distinguish between activities originating in different but adjacent locations.
what are the strengths of event-related potentials?
-bring much more specificity to the measurement of neural processes that could ever be achieved by just using raw EEG data.
-good temporal resolution
what are the limitations of event-related potentials?
-one issue is that, in order to establish pure data in ERP studies, background ‘noise’ and extraneous material must be completely eliminated, which is a problem because it may not anyways be easy to achieve.
what are the strengths of post-mortem examinations?
-Broca and Wernicke both relied on post-mortem studies in establishing links between language, brain and behaviour decades before neuroimaging ever became a possibility.
-also used to study HM’s brain to identify areas of damage, which could then be associated with his memory deficits, meaning post-mortems continue to provide useful information
what are the limitations of post-mortem examinations?
-raise ethical issues of consent from the individual before death as they may not be able to give informed consent.
-observed damge to the brain may not be linked to the deficits under review but to some other unrelated trauma or decay.