Visual II
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T/F:
The borders between layers of the primary visual cortex are quite distinct. - This is true. Addditionally, the border between V1 and V2 is very sharp.
- What type of neurons are most prevalent in layer IV? From where do they receive input? Where and with what other cells do they synapse?
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*stellate cells
*receive input via the optic radiations from the LGN
*synapse with pyramidal cells in layers II, III, V, and VI - How is visual information organized in layer IV? Is it segregated or integrated?
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*segregated by receptive field component (center vs. surround)
*segregated by eye into ocular dominance columns - Do neurons in layers II,III,V,VI receive information from one eye or the other or both eyes?
- They integrate information from both eyes to create a binocular visual field.
- How do neurons in layers II,III,V,VI perceive shape?
- Each neuron is selectively responsive to a particular contour (edge, orientation) of light.
- What are minicolumns?
- Vertical sections of V1 that contain neurons in each layer which are all responsive to the same contour of light.
- Do neurons in layers II,III,V,VI perceive motion?
- Yes - they are selectively responsive to a certain type of movement.
- Describe the projection of the retinal topography on the primary visual cortex.
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*topography is preserved but inverted vertically
*macula projects onto a disproportionately large area of the cortex - In what area does form recognition occur? Describe the path of information from V1 to this area.
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*temporal cortex
*V1 to V2 to V4 to temporal cortex (ventral pathway) - Where does recognition of motion occur? Describe the path of visual information from V1 to this area. What other visual task takes place here?
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*parietal cortex
*dorsal pathway: V1 to V2 to MT to parietal cortex
*visual attention - What effect does electrical stimulation of the MT have? Cooling?
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*stimulation creates the perception of movement
*cooling causes reversible loss of ability to perceive movement - What area of the brain mediates visual attention to objects in the left visual field? The right visual field?
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*Left field: right parietal cortex
*Right field: left and right parietal cortex