FNS 36 Central Visual Processing

  1. What are Ocular Dominance Columns?
    • Vertical column (all 6 layers)
    • Process information predominantly from one eye
  2. To which layer of an Ocular Dominance Column do LGB neurons project?

    Is this layer monocular or binocular?
    • Layer IV
    • Monocular
  3. What are orientation columns?
    • Smellere vertical slabs within ODCs
    • Cells respond to stimuli in a specific orientation
  4. What are Blobs?
    • Pillar-like cells in layers II-III and V-VI
    • Respond to color stimuli - exclusively from P-pathway
  5. What is a hypercolumn?
    • Combined adjacent right and left eye ODCs with orientation columns and several blobs
    • One per visual field point
  6. Which axons in the visual pathway converge?
    Several LGB axons --> one layer IV neuron
  7. What is a Simple cell?
    • Layer IV neuron sensitive to orientation specific elongated receptive fields
    • Have On/Off nature
  8. What is a Compex Cell?
    • Layer II-III, V-VI neuron sensitive to particularly oriented stimuli anywhere within the receptive field
    • Have greater convergence than Layer IV cells
  9. Describe the Dorsal Pathway
    • Continuation of the M-Pathway
    • To superior parietal cortex
    • Carries movement, orientation, contrast information
  10. Describe the Ventral Pathway
    • Continuation of the P-Pathway
    • To inferior temporal cortex
    • Carries high acuity, color sensitive information
  11. Define Visual Agnosia
    • Inability to recognize certain aspects of the visual image and/or identify objects
    • No loss of visual acuity
  12. Define Simultanagnosia, localize lesion
    • Difficulty perceiving more than one object at a time
    • Difficulty perceiving the meaning of the whole

    Lesion - bilateral superior parietal cortex (M-Path)
  13. Define Akinetopsia, localize lesion
    • Loss of motion perception
    • "Strobe light" view

    Lesion - bilateral superior parietal cortex (M-Path)
  14. Define Prosopagnosia, localize lesion
    • Inability to identify faces
    • Can recognize other objects

    Lesion - Bilateral inferior temporooccipital cortex (P-Path)
  15. Define Achromatopsia, localize lesion
    Cortical color blindness - loss of color vision

    • Lesion - Inferior occipitotemporal cortex (P-Path)
    • If unilateral lesion, one hemifield will be black/white, other hemifield in color
Card Set
FNS 36 Central Visual Processing
FNS 36 Central Visual Processing