neurology and experimental neuropsychology MRI magntic resonance imaging

Neurology and experimental neuropsychology mri

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neurology and experimental neuropsychology - MRI: magntic resonance imaging provides similar images but with greater spatial resolution
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- Both produe high-quality snapshots of human brain structures localize brain lesions, tumours, developmental abnormalities - But they don’t show brain activity - EEG: electroencephalography does that. Electrical signals from brain are recording by electrodes placed on scalp measures time course of flow of sensory info - event-related potential (ERP): electrical signal emitted by brain after onset of stimulus (represented by wave forms) these signals are averageed over great number of trials interesting patterns - Ex: Rugg study : participants shown series of words labelled S1, S2, S3 and S4 ERP associated with each was recorded the items that were remembered had differnet waveform that those that were forgot looks as though ERP can predict subsequent recall of items BUT not that easy maybe the differnt waveforms are due to the fact participants paid less or more attention to item etc ADV: great at giving time of brain electrical activity (temporal resolution) PB: not good at providing info on where this activity is occuring (spatial resolution) + requires a lot of experimental trials (couldn’t test things like autobiographical memory so ERP can suggest info, but additional techniques are required to get more complete pic of brian processes Positron Emission Tomography PET: an imaging technique in which a participant is injected with a radioactive substance that mingles with the blood and circulates to the brain. A scanner is then used to detect the flow of blood to aprticular areas of the brain. - Assumption: when specific function is engaged, only the parts of brain responsible for it will be engaged - Participant does task parts of brain responsible for task will work harder than when not doing task - So that part will use up oxygen at faster rate needs more oxygen blood flow to area - Detection of blood flow to area construct images of brain showing which parts are more active during which tasks - Pb : limit amount of radiation a person can be exposed to + high cost Functional Magnetic Imaging fMRI: a non-radioactive, magnetic procedure for detecting the flow of oxygenated blood to various parts of the brain - Measures flow of oxygen in blood while subject completes task correlates action of brain activity with cognitive behavior - Place subjets head in very large magnetic field show stimuli and make them do task - Neurological measurement of activity associated with function - Magnetic field causes atoms in brian to become aligned with it - When alterations in magnetic field changes in flow of oxygenated blood contrust image of cortical activity - Bavalier experiment: tasks: sentence reading and viewing of consonant strings - Results: wide individual differences in patterns of activity - Broca’s and Wernicke’s areas were more activated by sentence-reading task than by viewing consonant strings
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  • Winter '08
  • LEVITIN
  • Psychology, brain damage, Study of Brain Injuries

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