Physiology 3120 Lecture Notes - Postcentral Gyrus, Central Sulcus, Evoked Potential
Document Summary
Somatosensory system ii: somatosensory cortex located in the post-central gyrus (posterior/caudal to the central sulcus, properties (each hemisphere is organized this way) (1) somatotopic organization. Leg (medial) trunk arm face (lateral) This organizational structure is called a homunculus ( little man : distorted because of differences in density of receptors in a certain body part (highest in fingers & lips); more sensitive areas take up more cerebral surface area. Present at birth, but also shows cortical plasticity: example: Braille, the hand area of the cortex will expand someone who is born sighted, but later become blind & use to learn (2) columnar organization. All neurons in a column of cortex have very similar properties: modality-pure (particular type of receptor) on the same part of the body, faithful transmission.