Physiology 3120 Lecture Notes - Wilder Penfield, Precentral Gyrus, Somatotopic Arrangement

• School: Western University
• Department: Physiology
• Course: Physiology 3120
• Professor: Tom Stavraky

Document Summary

Motor cortex: techniques used to study function of particular brain region, stimulation. Magnetic: rapidly changing magnetic fields can induce currents in cortex) To reticular formation in pons & medulla. Evoked potentials & eeg (observe populations of neurons) Pet scan & fmri (record differences in blood flow to brain regions: motor cortex. Region from which low intensity stimulation elicits muscle contractions. Precentral gyrus (i. e. just anterior to central sulcus) Usually evoked flexion movement at a joint; elicit jerk-like movement because we elicit large numbers of neurons that don"t normally fire together. Movement is contralateral of stimulation: somatotopic organization. Equivalent to somatotopic organization of somatosensory cortex. Larger representations for the fingers & the face; therefore, there is a bigger area from which we can produce finger movement. Represents a distorted homunculus with larger representations for fingers & face. Hughlings jackson found that epileptic motor seizures move from medial to lateral (i. e. jacksonian march) Wilder penfield confirmed this hypothesis in stimulation studies.