CORTICAL PROCESSING: EXTRA-CLASSICAL RECEPTIVE FIELD

INFLUENCESINFLUENCES

Valentin Dragoi

Department of Neurobiology and Anatomy

Surround effects in retina

Center Response Surround Response Opponent Field Response

Neuronal circuits incircuits in striate cortex

Cells with i ilsimilar

function are linked through ghorizontal connections

Filling-in effect in visual cortex (De Weerd et alFilling in effect in visual cortex (De Weerd et al, 1995)

Stimulus collinearity: psychophysical y p y p yresults (Kapadia et al, 1995)

Stimulus collinearity: psychophysical y p y p yresults (Kapadia et al, 1995)

Stimulus collinearity in monkey visual cortex (Kapadia et al, 1995)

Center-surround interactions in primary visual cortex (adapted from Levitt and Lund 1997)visual cortex (adapted from Levitt and Lund, 1997)

A: spatial arrangement of the receptive field center and surround used to investigate contextual effects. The center ggrating stimulus is surrounded by a larger annulus field with the same mean luminance. B: responses to the high-contrast optimal center stimulus paired with high contrast surround gratings ofwith high-contrast surround gratings of varying orientations. Cells 1 and 2 are adapted from Fig. 1, A and D, of Levitt and Lund (1997) . C: responses to the low-contrast optimal center stimulus paired with high-contrast surround gratings of varying orientations. Cells 3 and 4 are adapted from Fig. 1, D and E, of Levitt and Lund (1997) . Dashed lines in all panels indicate response to the optimal stimulusindicate response to the optimal stimulus alone.

Model of center-surround interactionssurround interactions in primary visual cortex (Dragoi and Surcortex (Dragoi and Sur, 2000)

Orientation- and contrast-dependent suppression and facilitation. A: responses to high-contrast optimal center stimulus (contrast 100%) paired with high-contrast surround of varying orientation ( ) and to y g ( )surround stimulus alone ( ). Center contrast and surround orientation values are identical with those used by Levitt and Lund (1997) . B: responses to the low-contrast optimal center stimulus (contrast 15%) paired with a high contrast surround of varying15%) paired with a high-contrast surround of varying orientation ( ) and to the surround stimulus alone ( ). Center contrast and surround orientation values are identical with those used by Levitt and Lund (1997) . Dashed lines: response to the optimal stimulus alone (high center contrast value is 100% in A; low center contrast value is 15% in B).

Model of center-d i t tisurround interactions

in V1 (Dragoi and Sur, 2000)

Pop-out effect

What is the function of horizontal connections?

Geometrical illusions

Examples of geometrical illusions

Surround stimulation increases response sparseness in V1 (Vinje and Gallant, 2000)

Surround effects in rat somatosensoryycortex (Moore et al, 1999)

S ffSurround effects in rat somatosensorycortex (Moore et al, 1999)

Model of center-surround interactions in rat S1 (Moore et al, 1999)

Suggested readingsSuggested ead gs

1. De Weerd P, Gattass R, Desimone R, Ungerleider LG. Responses of cells in monkey visual cortex during perceptual filling-in of an artificial scotoma. Nature. 1995 Oct 26;377(6551):731-4.

2. Levitt JB, Lund JS. Contrast dependence of contextual effects in primate visual cortex. Nature. 1997 May 1;387(6628):73-6.

3. Kapadia MK, Ito M, Gilbert CD, Westheimer G. Improvement in visual sensitivity by p p y ychanges in local context: parallel studies in human observers and in V1 of alert monkeys. Neuron. 1995 Oct;15(4):843-56.

4. Vinje WE, Gallant JL. Sparse coding and decorrelation in primary visual cortex during j p g p y gnatural vision. Science. 2000 Feb 18;287(5456):1273-6.

5. Moore CI, Nelson SB, Sur M. Dynamics of neuronal processing in rat somatosensorycortex. Trends Neurosci. 1999 Nov;22(11):513-20. Review.( )