-
What are Ocular Dominance Columns?
- Vertical column (all 6 layers)
- Process information predominantly from one eye
-
To which layer of an Ocular Dominance Column do LGB neurons project?
Is this layer monocular or binocular?
-
What are orientation columns?
- Smellere vertical slabs within ODCs
- Cells respond to stimuli in a specific orientation
-
What are Blobs?
- Pillar-like cells in layers II-III and V-VI
- Respond to color stimuli - exclusively from P-pathway
-
What is a hypercolumn?
- Combined adjacent right and left eye ODCs with orientation columns and several blobs
- One per visual field point
-
Which axons in the visual pathway converge?
Several LGB axons --> one layer IV neuron
-
What is a Simple cell?
- Layer IV neuron sensitive to orientation specific elongated receptive fields
- Have On/Off nature
-
What is a Compex Cell?
- Layer II-III, V-VI neuron sensitive to particularly oriented stimuli anywhere within the receptive fieldHave greater convergence than Layer IV cells
-
Describe the Dorsal Pathway
- Continuation of the M-Pathway
- To superior parietal cortex
- Carries movement, orientation, contrast information
-
Describe the Ventral Pathway
- Continuation of the P-Pathway
- To inferior temporal cortex
- Carries high acuity, color sensitive information
-
Define Visual Agnosia
- Inability to recognize certain aspects of the visual image and/or identify objects
- No loss of visual acuity
-
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)
-
Define Akinetopsia, localize lesion
- Loss of motion perception
- "Strobe light" view
Lesion - bilateral superior parietal cortex (M-Path)
-
Define Prosopagnosia, localize lesion
- Inability to identify faces
- Can recognize other objects
Lesion - Bilateral inferior temporooccipital cortex (P-Path)
-
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
|
|
