BIOLOGY 2C03 Lecture Notes - Internal Arcuate Fibers, Spinothalamic Tract, Cuneate Nucleus
28 Jan 2013
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For example, proprioception (body position), mechanoreception, pain, itch, temperature, stereognosis (3d form), muscle force. Somatotopy: mapping of body surface to set of neurons. Cortical magnification: defined as cortex area/body area, highest for face, hand, feet and lowest for back. Area 3a: proprioception (muscles and joint angle) Area 3b: spatial temporal acuity (sa1 form and texture, ra1 grip control) Columns in cerebral cortex about 500 m m wide usually have same modality and receptive field (e. g. in 1 visual system, alternating columns) Plasticity: amputation causes changes in somatotopic map in si. Two ascending pathways: spinothalamic system (aka anterolateral system) Mechanoreception and proprioception afferent enter dorsal horn of spinal cord medial to. Lissauer"s tract ascend in gracile (below t6) or cuneate (above t6) fasciculus synapse in gracile or cuneate nucleus cross midline via internal arcuate fibers ascend through medial lemniscus to vpl of thalamus. Be aware of somatotopic organization in the two pathways (position of head and feet)
