CH 15 Nerve Pathways for Vision

Exam 4 Review: Chapter 15: Nerve Pathways for Vision

optic nerves - The second pair of pure sensory cranial nerves (II) which arise from the ganglion cells of the retina, exit at the optic disc, partially decussate at the optic chiasma, and carry visual information to the thalamus and other parts of the brain, especially the primary visual cortex.

optic chiasma = optic chiasm - A structure at the base of the brain, just anterior to the mamillary body and the infundibulum of the pituitary gland, formed by the partial intersection or crossing of the optic nerve fibers on the underside of the hypothalamus where some (75%), but not all, optic information crosses to the contralateral side of the brain.

optic tracts - The portion of the visual system pathway from the optic chiasm to the lateral geniculate nucleus of the thalamus; each optic tract contains axons from ganglion cells in the retinas of both the left and right eyes, but information from only one half (i.e., either left or right) of each eye's visual field.

primary visual cortex - The extreme posterior tip of the occipital lobe of the cerebral hemisphere and the tissue deep in the calcarine sulcus; the largest of all cortical sensory areas, it receives visual information which originated at the retinas of the eyes; there is a contralateral map of visual space on the primary visual cortex, with the representation of the image inverted as it was received on the retina.