PSYC 2220 Lecture Notes - Lecture 4: Functional Magnetic Resonance Imaging, Radioactive Tracer, Ferrous
14 Oct 2015
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Document Summary
Cortical magnification: refer to the physical phenomenon that the percentage area of vision on fovea will expand when the same image is processing in the cortex. Cortical mapping methods: positron emission tomography (pet): Person is injected with harmless radioactive tracer. Changes in blood flow changes in brain activity. Subtracting the control activity from the stimulation activity: functional magnetic resonance imaging(fmri) Hemoglobin carries oxygen and contains a ferrous( ) molecules that is magnetic. Brain activity takes up oxygen, which makes the hemoglobin more magnetic. Fmri determines activity of areas of the brain by detecting changes in magnetic response of hemoglobin( ) Subtract just like pet location: receptive fields at the same location on the retina are within a column visual cortex organized in columns according to: Orientation: receptive the fire when stimulated by the same orientation on retina are within a column. Adjacent columns change preference in an orderly fashion. 1 mm across the cortex represent entire range of orientation.
