the visual system iv the visual cortices. the primary visual pathway from perret-optic.ch
Post on 20-Dec-2015
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The visual system
IV
The visual cortices
The primary visual pathway
From perret-optic.ch
Primary vision
Structure of the primary visual cortex-
The headquartes
Information flow
2/3
1
4b4a
4cα
5
4cβ
6
PM
Higher areas
Higher areas
Intra V1
Intra V1
Superior colliculus, pulvinar, pons
LGN, thalamic interneurons
Visual columns-RFs and orientations
200 μm
Orientation map
How does orientation selectivity arise?
Ferster et al. (1996), Reid & Alonso (1996)
Receptive fields in different cortical layers
Layers IV and VI
Simple cells
Layers II and III
Complex cells
Are complex cells more complex, or just more active?
Adapted from Kandel et al. (2000)
Complex cell!
Are complex cells more complex, or just more active?
Crowder et al. (2007)
Higher visual areas:The Where and What
Magnocellular!
Parvocellular!
Higher visual areas:Inferotemporal cortex
Fusiform face area
Halle Berry Cells
Halle
Berry
Contour perception is fed back to V1
Lamme (1995)
Higher visual areas:The Where and What
Magnocellular!
Parvocellular!
Motion perception is fed back to V1
Muckli et al. (2005)
Summary IV – The visual cortex…
• continues the segregation in magno- and
parvocellular pathway as the Where and What
pathway
•is segregated into six layers, all of which fulfill
different tasks in coordinating activity from the
thalamus, other cortical areas and the brain stem
• is organized in response preference columns,
according to ocular dominance, stimulus orientation,
contrast, length etc.
• contains neurons with simple and complex
responses
•is in constant feedback-feedforward loops with the
Where and the What pathways