Neuroscience 2004 Abstract
| Presentation Number: | 18.5 |
|---|---|
| Abstract Title: | Spatial extent of image completion in primary visual cortex. |
| Authors: |
Malone, B. J.*1
; Ringach, D. L.1,2,3
1Neurobiology, UCLA, Los Angeles, CA 2CA, 10833 Le Conte Ave, 90048, 3USA, 10833 Le Conte Ave, 90048, |
| Primary Theme and Topics |
Sensory Systems - Vision -- Visual cortex: Neural coding |
| Session: |
18. Visual Cortex: Maps and Organization Slide |
| Presentation Time: | Saturday, October 23, 2004 2:00 PM-2:15 PM |
| Location: | San Diego Convention Center - Room 24A |
| Keywords: | VISUAL CORTEX, VISUAL PERCEPTION, PRIMATE, RECEPTIVE FIELD |
The visual system is able to complete portions of visual scene that lack structure by incorporating contextual information about color, texture, and contours from the surrounding area. We previously demonstrated (SFN, 2003) that many neurons in primary visual cortex (V1) can rapidly interpolate the structure in an image occluded by a mask centered on their receptive fields. We used a subspace reverse correlation technique to estimate the linear kernels of simple cortical cells in two conditions: 1) a full-view condition consisting of a rapid sequence of high-contrast sine wave gratings drawn from a Hartley (sinusoidal gratings) basis set, and 2) a masked condition, which consisted of the same grating stimuli and a uniform grey mask centered on the receptive field and scaled to occlude nearly half of its area. Here we extend these observations by studying how image completion depends on the spatial extent and location of the mask. We used multi-electrode arrays to simultaneously record from a population of V1 simple cells during the presentation of a mask. As a result of this experimental design, the mask overlapped in different degrees with the receptive fields under measurement and its location relative to the receptive field varied as well. We found that V1 neurons were unable to interpolate visual information as soon as the masked area was large enough to cover the classical receptive field of the neuron. When the mask occluded only a part of the receptive field, either at the ends or the flanks, some neurons showed signs of image completion. The clearest examples of image completion occurred in neurons that were well-tuned for orientation and spatial frequency. Our results suggest that the local circuitry in V1 may work to restore the structure of the image in cases where some of the feed-forward signals are unreliable or absent, such as those induced by small retinal scotomas.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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