Exam 3 Week 14 ppt 5 visual cortex Flashcards
Brodman’s areas of visual cortex
–Foveal area (1) most posterior
–Peripheral areas more rostral (2 & 3)

Where does visual pathway end retinotopically?
around the calcarine sulcus of the primary visual cortex
Where do some axons of the optic radiation terminate?
visual association cortex
How is visual cortex organized?
(draw/imagine a picture)
functional columns

Functional columns- principle LGN input to ____
layer IV
Matrix of overlapping columns
(name the three columns)
–Ocular dominance columns
–Orientation columns
–Blobs

Ocular dominance columns- 3 points to know
- Respond with preference to right or left eye
- Largest of column structures
- Alternating eye dominance
Orientation columns- 2 points to know
- Contain simple & complex cells don’t respond to points of light but bars of light only in certain orientations
- Adjacent columns related but different orientation

What do simple cells do?
- Respond to bars of light only in a certain orientation with inhibitory surround
- Convergence of LGN cells
What do complex cells do?
- Respond to bars of light only in a certain orientation but not have inhibitory surround
- respond with movement of the bar of light in one direction
- represent summation of several simple cells
What does MaryBeth wish she were doing right now?
Recieving a massage and then eating some pizza
Where are blob columns located?
–Located in layers II & III
–Divided into blobs & interblob regions

Purpose of blob columns
–Blobs for color processing
–Interblob regions for form processing
What is the Modular Organization of the visual cortex?
–2x2 mm areas of 1° visual cortex
–Each Module contains a
- 360° of orientation columns
- Set of of left & right ocular dominance columns
- Set of 16 blobs & interblob regions for color and form discrimination
–Each module is interconnected with adjacent modules
Binocular organization
–Layer IV cells of a single ocular dominance column are monocular
–Interconnections between adjacent columns and layers produces binocular vision

Brodmann’s areas for visual association cortex and subdivision
Brodmann areas 18 & 19 and is divided into pre-striate cortex (V2) and Extra-striate (V3)

Pre-striate cortex – V2 (5 points to know)
- Complete map of the visual world
- More complex orientation, spatial frequency, and color characteristics than the primary cortex
- Response to illusory contours
- Respond to whether the stimulus is part of the figure or the ground
- part of Attentional modulation
Extra-striate cortex – V3 (2 points to know)
- Global motion
- Parts of dorsal & ventral streams
Why do I care about Figure-Ground relationships?
allow us to detect objects from their background. It also gives us a form of visual illusion
Where is the Dorsal Stream?
Projections from area 18 visual association cortex to the parieto-occipital cortex (posterior parietal cortex)
Importance of dorsal stream
–Important for analyzing motion and spatial orientation within the visual field navigate around it, and manipulate objects within it
What happens if there is damage to dorsal stream?
Damage in this area produces visual apraxia:
- an object is seen, and identified, but cannot be used.
- Functional significance is lost
- Example can identify a comb by sight, but cannot pick it up and comb hair
Where is the ventral stream?
Projections to the occipito-temporal cortex and inferior temporal cortex for
- identification of the object
- identification of complex stimuli such as faces
- further verbal manipulation
Damage to ventral stream results in ______
- visual agnosia – inability to name an object even though it is seen
- produces prosopagnosia, the inability to identify people by their faces