PSL440Y1 Study Guide - Final Guide: Central Artery, Hypothalamus, Lisa Lopes
Document Summary
The retina provides basic information (already slightly processed at retinal level: sensitivity/motion, colour, contrast. The brain must convert retinal images into identifiable objects (visual information that informs perception of world) Objects must be placed correctly in the visual scene. Changes in luminance, contrast, and colour result in changes in action potential frequency from individual ganglion cells. Ganglion cell axons coalesce at the optic disk and bundle to form the optic nerve. The optic nerve is myelinated as it leaves each eye, and runs straight to the optic chiasm, where 60% cross to the opposite side. Recall: retinal ganglion and bipolar cells responds to small patch of photoreceptors, called their receptive field the first (and most well studied) receptive field responds to contrast: on-center and off-center, mediated by lateral inhibition. Tissue in the optic nerve head adapted to provide structural support to this sensitive region. Pores are formed by collagen fibrils and astrocyte processes for ganglion cell axons to pass through.
