BIOLOGY 2C03 Lecture Notes - Calcarine Sulcus, Foveal, Pupillary Light Reflex
28 Jan 2013
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Document Summary
Visual system i central visual pathways: optic nerve and tract. Axons in the optic nerve cross at the optic chiasm so that each optic tract represents the contralateral visual field. There are three major visual pathways: optic tract lgn primary visual cortex (higher visual processing, optic tract superior colliculus (saccades, optic tract pretectum (pupillary light reflex, lateral geniculate nucleus (lgn) Visuotopic map: central retina posterior lgn, peripheral retina anterior lgn. Lgn is made of 6 layers: magnocellular 1,2 and parvocellular 3-6. Ipsilateral retina maps to layers 2,3,5 (prime!) and contralateral to 1,4,6. Lgn neurons have receptive fields that resemble on- and off-center ganglion cells. Intralaminar cells respond to blue light only, may be responsible for color. Lgn projects dorsally to v1 in the occipital lobe with inferior-superior inversion with respect to visual field. Columns in lgn project to same part area of v1 (recall that layer 4 receives thalamic input)
