PSYC 311 Chapter Notes - Chapter 2: Hemianopsia, Occipital Lobe, Superior Colliculus
6 Dec 2016
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Document Summary
In the retina the receptive field consists of receptors (rods, cones) and retinal neurons, which influence the excitability of a single ganglion cell. The ganglion cell is what transmits the signal to the visual cortex, via the convergence of its axons into the optic nerve. The axons of the ganglionic neurons give rise to the optic nerve. The rod and cone cells are visual receptors which react specifically with physical light. Cones: ~ 7 million in the eye, higher threshold of excitability, stimulated by light of relatively high intensity, responsible for sharp visual definition and for color discrimination. Rods: ~ 100 million in the eye, react at low intensities of light, responsible for night vision. The rest of the retina is concerned with peripheral vision. Fovea centralis: the point of sharpest vision and most acute color discrimination. Here the retina is composed entirely of closely packed cone cells.
