Judah De Paula

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Modeling color selective maps and neurons in the
visual cortex

• Judah De Paula
• April 10, 2005
• University of Texas, Austin
• Neuroscience Retreat

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Why study color vision?

• Understand how the brain can organize complex
  stimuli
• Color is an integral part of vision
• Robots will need color to interact with humans
• Help understand color blindness in human patients
• How does color increase salience?

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Overview

• Introduction
• Biology
• Model
• Results

You are here
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Vision physiology in the retina

• Rods not used in daylight
• Fovea consists of cones
• Cone wavelength sensitivity functions overlap
  each other
• Only Long (Red) and Medium (Green) wavelength
  cones found in fovea.

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Vision Anatomy

• Retina LGN Primary Visual Cortex

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V1 Optical Imaging (Landisman et al.)
Macaque monkey, Landisman and Tso
1mm
A Color selectivity map B Orientation map C
Color map with orientation pinwheels D
Orientation map with pinwheels and color map
overlaid
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V1 Optical Imaging (Landisman et al.)

• How are these maps created in the cortex?
• How do the color, orientation, and O.D. maps
  interact?
• Landisman suggests ocular dominance is more
  related to color than orientation maps. Is this
  generally true?

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Color Opponent LISSOM

• Each Cell Type in the LGN is represented with a
  separate Sheet between Photoreceptors and V1
• Each Sheet has a receptive field with a different
  Gaussian function
• LISSOM adjusts for different numbers of LGN
  Sheets
• Works with natural images

Bednar, De Paula, Miikkulainen. 05
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Cone type distribution

• Random distribution of cone types. No S-cones in
  fovea
• Ratio between L-M differs between patients 0.251
  to 91 without loss of color selectivity
  (Brainard et al. 2000)

Lennie, 2000
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Color Opponent LGN cells
Existing Model

• Lateral Geniculate Cells
• Long Center / Medium Surround
• Medium Center / Long Surround
• LM Center / LM Surround
• Add S Center / LM Surround

Red-Green L / M-
Luminosity (ML) / (ML)-
Green-Red M / L-
Blue-Yellow S / (ML)-
Proposed
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LISSOM Model
LISSOM ? Laterally Interconnected Synergetically
Self-Organizing Map (Sirosh,
Choe, Bednar, Miikkulainen 93-04)
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Modeled orientation preference in V1

• Patches develop for each orientation
• Similar to animal maps
• Some areas not orientation selective (White
  regions)

Bednar, De Paula, Miikkulainen. 05
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Modeled color preference in V1
Color preferring regions found with solid-field
test stimuli
Bednar, De Paula, Miikkulainen. 05
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Orientation/Color overlay
Color selective blobs (outlined) match to OR
unselective regions
Bednar, De Paula, Miikkulainen. 05
Completed work similar to Cytochrome Oxidase
blobs observed in biological V1
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Discussion

• Uses for a cortical model of color vision
• Computer Science robotic vision
• Neuroscience mechanism for organization
• Psychology origin of perceptual experience
• Add short cone opponent cells to LGN for
  trichromatic vision
• Add V2 region
• Test for functional stripes
• Test for Hue organized color selectivity

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References

• http//www.phys.ufl.edu/avery/course/3400/gallery
  
• http//webvision.med.utah.edu/Color.html
• Miikkulainen, Risto and Bednar, James A. and
  Choe, Yoonsuck and Sirosh, Joseph (1997)
  Self-Organization, Plasticity, and Low-level
  Visual Phenomena in a Laterally Connected Map
  Model of the Primary Visual Cortex, Psychology of
  Learning and Motivation, volume 36 Perceptual
  Learning, pp. 257-308.
• Kandel, Schwartz, and Jessell. Principles of
  Neural Science Third Edition 1991.
• James A. Bednar and Risto Miikkulainen (2003).
  Self-Organization of Spatiotemporal Receptive
  Fields and Laterally Connected Direction Maps,
  Neurocomputing 52-54473-480.
• http//www.brainfiber.com/flowers.jpg
• Lennie P. 2000. Color vision putting it
  together. Curr. Biol. 10(16)R589-91
• Landisman, Carole and Tso Daniel. Color
  Processing in the Macaque Striate Cortex
  Relationships to Ocular Dominance, Cytochrome
  Oxidase, and Orientation.
• Kandel, Schwartz and Jessell. Principles of
  Neural Science. McGraw Hill. 2000
• Shipp and Zeki. The func. org. of area V2, II
  The impact of stripes on visual topography. Vis
  Neurosci. Iss. 19, 211-231. 2002.
• Sincich and Horton. Pale cytochrome oxidase
  stripes in V2 receive the richest projections
  from macaque striate cortex. J. Comp. Neuro.
  44718-33
• Xiao and Fellerman. Projections from primary
  visual cortex to cytochrome oxidase thin stripes
  and interstripes of macaque visual area 2. PNAS
  1017147-7151
• Tootell, Nelissen, Vanduffel and Orban. Search
  for Color Center(s) is Macaque Visual Cortex.
  Cerebral Cortex 2004. 14353-363.
• Clarke, Walsh and Schoppig. Colour constancy
  impairments in patients with lesions of the
  prestriate cortex. Exp. Brain Res. 123154-158
• Xiao, Wang and Fellerman. A spatially organized
  representation of colour in macaque cortical area
  V2. Nature 412535-539

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Red-Green Receptive Field Spike Trains
Adapted from Kuffler, 1953