Neurophys E1 NS - Advanced Neurophysiology Exam 1 Spring 2006 Weapons in Neurophysiologists Armory Nicole M Schmidt Palmer College 1 Recording a

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Advanced Neurophysiology Exam 1 Nicole M. Schmidt Spring 2006 Palmer College 1 Weapons in Neurophysiologist’s Armory 1. Recording a. individual neurons b. gross potentials c. brain scans 2. Stimulation 3. Lesions – experimental and natural 3 major cell types in Cerebral Cortex 1. Pyramidal cells - source of corticospinal projections - major efferent cell 2. Granule cells (Stellate) – short axons - function as interneurons (intracortical processing) - excitatory neurons release primarily glutamate - inhibitory neurons release primarily GABA 3. Fusiform cells - least numerous of the three - give rise to output fibers from cortex Cerebral Cortex Layers Layer I Molecular Layer mostly axons Layer II External Granular Layer granule (stellate) cells Layer III External Pyramidal Layer primary pyramidal cells Layer IV Internal Granular Layer main granular cell layer Layer V Internal Pyramidal Layer giant pyramidal cells Layer VI Multiform Layer all 3 types Function of Layers Layers I, II, III - perform most of the intracortical association functions - large number of neurons in II and III which make short horizontal connections with adjacent cortical areas Layer IV - most incoming sensory signals terminate here Layers V, VI - most output leaves from these layers - spinal cord tracts originate from layer V - thalamic connections originate from layer VI Thalamocortical System refers to the fact that all areas of cerebral cortex have extensive afferent and efferent connections with deeper structures of brain (basal ganglia, thalamus, etc.), with exception of some sensory pathways of olfaction These connections are extremely important and extensive Thalamic excitation of the cortex is necessary for almost all cortical activity. Plasticity of Cerebral Cortex Cortical neurons, especially in association areas can change their function as functional demand changes. Ex: occipital areas are used by blind people while reading Braille Secret of the Cerebral Cortex The network of links between neurons in the cortex mimics relationships between things in the outside world—cortex can process the code of information coming in. The cortex makes a probabilistic model of the world which can predict what is likely to happen next. The cortex changes the strength of connections to reflect observed associations (to match experience). Neurons that are often active at the same time become physically connected—neurons that “fire together, will eventually wire together.” Examples: - increased ability to palpate with experience - increased sensitivity to different smells/tastes with practice - dysfunctional behavior Association Areas integrate or associate information from diverse sources
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Advanced Neurophysiology Exam 1 Nicole M. Schmidt Spring 2006 Palmer College 2 comprise a large percentage of the cerebral cortex hold a high level in the hierarchy (3 o , 4 o , 5 o ) Lesions here have a subtle and unpredictable quality (compared to lower level lesions which cause gross changes).
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This note was uploaded on 05/03/2011 for the course PHYS 3 taught by Professor Free during the Spring '11 term at Palmer Chiropractic.

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Neurophys E1 NS - Advanced Neurophysiology Exam 1 Spring 2006 Weapons in Neurophysiologists Armory Nicole M Schmidt Palmer College 1 Recording a

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