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| Research article summary (published 29 Apr 2009): |
A precise form of divisive suppression supports population coding in the primary visual cortex.
Full Abstract
The responses of neurons in the primary visual cortex (V1) to an optimally oriented grating are suppressed when a non-optimal grating is superimposed. Although cross-orientation suppression is thought to reflect mechanisms that maintain a distributed code for orientation, the effect of superimposed gratings on V1 population responses is unknown. Using intrinsic signal optical imaging, we found that patterns of tree shrew V1 activity evoked by superimposed equal-contrast gratings were predicted by the averages of patterns evoked by individual component gratings. This prediction held across contrasts, for summed sinusoidal gratings or nonsumming square-wave gratings, and was evident in single-unit extracellular recordings. Intracellular recordings revealed consistent levels of suppression throughout the time course of subthreshold responses. These results indicate that divisive suppression powerfully governs population responses to multiple orientations. Moreover, the specific form of suppression that we observed appears to support independent population codes for stimulus orientation and strength and calls for a reassessment of mechanisms that underlie cross-orientation suppression.
Author information
Author/s: MacEvoy, Sean P (SP); Tucker, Thomas R (TR); Fitzpatrick, David (D);
Affiliation: Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA. macevoy(-atsign-)psych.upenn.edu
Grants: EY016319 (Agency:NEI NIH HHS) ; EY06821 (Agency:NEI NIH HHS)
Journal and publication information
Publication Type: Journal Article; Research Support, N.I.H., Extramural
Journal: Nature neuroscience (Nat Neurosci), published in United States. (Language: eng)
Reference: 2009-May; vol 12 (issue 5) : pp 637-45
Dates: Created 2009/04/28; Completed 2009/06/24; Revised 2009/10/09;
PMID: 19396165, status: MEDLINE (last retrieval date: 10/9/2009, IMS Date: )
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
Comments and Corrections
ErratumIn: Nat Neurosci. 2009 Jun;12(6):808.
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