16 terms

Neuro-Visual System

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Eye layers
Outer sclera & cornea, middle iris & choroid (tapedum lucidum), inner retina
Blood Occular barrier
Formed by the retinal pigmented epithelium and endothelium of retinal capillaries to keep eye immuno-privaleged
Optic Layers of Retina (inside to out)
ILM, Optic n. fibers, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, ELM, Rods and Cones, pigmented epithelium
*8 layers for light to pass through for rods and cones*
Photoreceptors (red light)
Rods and Cones that that transduce light→electrical activity; exicited/depolarized in the dark, inhibited/hyperpolarized in the light
Bipolar Cells
Cells that receive input from photoreceptors and synapse on ganglion cells *Depolarized ON and Hyperpolarized OFF*
Ganglion Cells (blue light)
Cells with axons that leave retina and *form the optic nerve*.
Horizontal Cells and Amacrine Cells
*inhibitory* cells that function in lateral pathways to enhance *CONTRAST*
Rhodopsin
Photosensitive molecule associated with rods and cones for intercepting photons (light→GMP→hyperpolarized)
Rods
Most numerous photreceptor with high sensitivity, obscure function in *dim light w/o color sensitivity*
Converge-many rods/ganglion cell
Cones
Photoreceptors concentrated in the Area Centralis, detailed funtion in *bright light w/ color sensitivity* (blue & yellow in dogs)
Relay-few cones/ganglion cell
"ON" cells
Bipolar and ganglion cells that specialize in detecting *INCREASED BRIGHTNESS*= increased firing
"OFF" cells
Bipolar and ganglion cells that specialize in detecting *DECREASED BRIGHTNESS*= increased firing
M Ganglion cells
Ganglion with large receptive fields for motion, position and depth
P Ganglion Cells
Ganglion with small receptive fields for fine detail and color
Conscious vision
Retina→lateral geniculate→cortex (binocular-input from both eyes simultaneously)
Reflex vision
Retina→rostral colliculus (eye, ear, head turn)
Retina→pretectal region (pupil size regulation)