Ways of investigating the brain Flashcards
Ways of investigating the brain
list
Functional magnetic resonance imaging (fMRI)
Electroencephalogram (EEG)
Event-related potentials (ERPs)
Port-mortem examinations
Functional magnetic resonance imaging (fMRI)
└a method used to measure brain activity while a person is performing a task that uses MRI technology (detecting radio waves from changing magnetic fields)
└enables researchers to detect which regions of the brain are rich in oxygen and are thus active
└produces 3D images (activation maps)
└important in localisation of function
Functional magnetic resonance imaging (fMRI)
strengths
└doesn’t rely on use of radiation= risk free, non-invasive, easy to use
└like PRT scans do
└images have high spatial resolution
└clear picture of how brain activity is localised
Functional magnetic resonance imaging (fMRI)
limitations
└expensive
└only clear image if person completely still
└poor temporal resolution
└5 second time lag behind image on screen and initial firing of neural activity
└don’t know what type of brain activity, only the location
Electroencephalogram (EEG)
└record of the tiny electrical impulses produced by brain activity
└can help diagnose certain conditions of the brain
Electroencephalogram (EEG)
strengths
└good in epilepsy diagnosis
└random bursts of activity in the brain can be easily detected on screen
└contributed to understanding of sleep stages/ultradian rhythms
└high temporal resolution
└within a single millisecond
Electroencephalogram (EEG)
limitations
└generalised nature of information
└don’t know location of activity
└can’t distinguish between activities originating in different but adjacent locations
Event-related potentials (ERPs)
the brains electrophysiological response to specific sensory, cognitive or mot or even can be isolated through the statistical analysis of EGG data
└statistical averaging technique
└filters out extraneous brain activity from original EGG recording
└leaves event-related potentials
└(types of brainwave that are triggered by particular events)
└linked to cognitive processes e.g. attention, perception
Event-related potentials (ERPs)
strengths
└partially addresses the limitations of EEGs
└good temporal resolution (compared to fMRI)
└use in measurement of cognitive functioning and deficits
└researchers have identified many different types of EPR and describe the precise role of these in cognitive functioning
└e.g. P300 component- involved in allocation of attentional resources and the maintenance of working memory
Event-related potentials (ERPs)
limitations
lack of standardisation in ERP methodology between different research studies
└=difficult to confirm findings
└not easy to eliminate noise and extraneous material to establish pure data
Port-mortem examinations
└the brain is analysed after death to determine if certain behaviours I the patient’s lifetime can be linked to abnormalities in the brain
└areas of damage are examined to establish likely cause of disorder
└can compare with neurotypical brain
Port-mortem examinations
strengths
└provided a foundation for early understanding of key processes in the brain
└Broca and Wernicke both relied on post mortem studies
└in establishing links between language, brain and behaviour
└decades before neuroimaging techniques
└improve medical knowledge
└help generate hypotheses for further study
Port-mortem examinations
limitations
└may not be causation
└observed brain damage may not be linked, instead some other trauma or decay
└ethical issues- consent from patient before death
└may not be able to provide informed consent
└e.g. case of HM who couldn’t form memories
