Global inhibition and stimulus competition in the owl optic tectum

Shreesh P. Mysore, Ali Asadollahi, Eric I. Knudsen

Research output: Contribution to journalArticlepeer-review

Abstract

Stimulus selection for gaze and spatial attention involves competition among stimuli across sensory modalities and across all of space. We demonstrate that such cross-modal, global competition takes place in the intermediate and deep layers of the optic tectum, a structure known to be involved in gaze control and attention. A variety of either visual or auditory stimuli located anywhere outside of a neuron's receptive field (RF) were shown to suppress or completely eliminate responses to a visual stimulus located inside the RF in nitrous oxide sedated owls. The essential mechanism underlying this stimulus competition is global, divisive inhibition. Unlike the effect of the classical inhibitory surround, which decreases with distance from the RF center and shapes neuronal responses to individual stimuli, global inhibition acts across the entirety of space and modulates responses primarily in the context of multiple stimuli. Whereas the source of this global inhibition is as yet unknown, our data indicate that different networks mediate the classical surround and global inhibition. We hypothesize that this global, cross-modal inhibition, which acts automatically in a bottom-up manner even in sedated animals, is critical to the creation of a map of stimulus salience in the optic tectum.

Original languageEnglish (US)
Pages (from-to)1727-1738
Number of pages12
JournalJournal of Neuroscience
Volume30
Issue number5
DOIs
StatePublished - Feb 3 2010
Externally publishedYes

ASJC Scopus subject areas

  • General Neuroscience

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