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What is the order of the visual pathway to the brain?
Retina → Optic Nerve → Optic Chiasm → Optic Tract → Lateral Geniculate Nucleus (LGN) → Striate Cortex (V1)
Where do 90% of light signals go?
Lateral Geniculate Nucleus (LGN)
Where do the other 10% go?
Superior colliculus and other subcortical structures
What brain regions send feedback to the LGN?
Primary visual cortex (V1) and other higher cortical areas
What are other names for the striate cortex?
Primary visual cortex, V1
How are receptive fields organized in the striate cortex?
In a retinotopic map
What are simple cortical cells?
Neurons that respond to specific orientations of bars of light
What are the three types of feature detectors?
Simple cells, complex cells, end-stopped cells
What do complex cells detect?
Movement of oriented bars of light
What do end-stopped cells detect?
Length, corners, or angles of moving stimuli
What is selective adaptation?
A process where neurons decrease their firing rate after prolonged exposure to a stimulus
What is selective rearing?
A process where exposure to a specific stimulus increases neural responsiveness
What is neural plasticity?
The ability of neurons to change their response properties based on experience
What is a retinotopic map?
A spatial organization of visual information in the cortex that preserves retinal layout
What is cortical magnification?
The distortion where the fovea has a disproportionately large representation in V1
What percentage of the retina is the fovea?
About 0.01%
How much of V1 does the fovea occupy?
8-10%
What are location columns?
Columns in V1 that process information from the same retinal location
What are orientation columns?
Columns that respond to specific stimulus orientations
What are hypercolumns?
A combination of location, orientation, and ocular dominance columns
What are the two visual processing streams?
The ‘what’ (ventral) pathway and ‘where/how’ (dorsal) pathway
What is the object discrimination problem?
The task of identifying an object based on its shape
What is the landmark discrimination problem?
The task of identifying an object’s location relative to another object
What does the ventral pathway process?
Object identification (‘what’)
