Central Visual Pathways Flashcards
Magnocellular layers
Layers 1 and 2
Receive large alpha type RGCs w large receptive fields primarily from rods in peripheral retina.
Lateral geniculate body
Receives 80-90% of retinal ganglia cells! and is organized into 6 fnxnl layers
Parvocellular layers
3-6
Receive beta type RGCs receive from cones and process high acuity color visions
Temporal retina axons
Go to the Ipsilateral lat gen in layers 2, 3, and 5
Nasal retinal axons
Project contra laterally to the lat gen body of layers 1, 4, 6
Optic radiations
Projections from the lat gen go to Ipsilateral visual cortex
Have two primary bundles, one that goes to superior bank of calcarine sulcus and one that ges to the inferior.
The inferior projection has the Meyers loop and the differences in the paths makes portions of the op rad susceptible to different vascular lesions.
Superior visual fields
Represented on the inferior banks of the calcarine area
Inferior visual fields
are represented on the superior banks of calc area
Peri feral fields and central, macula and fovea
Represented rostrally and caudally respectively
Striate cortex
The visual cortex is known as the striate cortex because of the band of gennari in the 4th layer of the cortex
Cortical columns
Respond to complicated patterns of light
Have two main cell types
Simple and complex
Simple cells
Respond to a bar of light with a particular orientation
Complex cells
Respond to the same stimuli as simple but over a larger are of visual space and maximally.
Have selective sensitivity for direction and are thought to be innervated by different patterns of cortical simple cells.
