PSYC 372 Lecture Notes - Lecture 6: Retinal Ganglion Cell, Lateral Geniculate Nucleus, Visual Cortex

• School: George Mason University
• Department: Psychology
• Course: PSYC 372
• Professor: Beatty

Document Summary

Magnocellular ganglion cells: detect movement of a visual stimulus and parvocellular detect fine details: pathways from the eye to the brain. Axons of ganglion cells (the optic nerve) have three targets in the brain that give rise to separate visual pathways: retinohypothalamic pathway: pathway by which variation in light levels influences sleep/wake circadian rhythm (natural sleep wake cycles) Going from the retina to the hypothalamus: ganglion cell axons project to the suprachiasmatic nucleus (scn) of the hypothalamus; sits over the optic chiasm. Ganglion cells projecting to the scn express the photopigment melanopsin. Does not depend on signals from rods & cones; blind mammals still have a sleep/wake circadian rhythm. Axons of scn neurons project to the pineal gland to direct production of the hormone melatonin in response to light levels; melatonin is synthesized from serotonin at night (low light levels)