Department of Psychology
Department of Psychology

"Attention-dependent reductions in response variability: underlying mechanisms"

Tue, November 6, 2012 | SEA 4.244

4:00 PM - 5:00 PM

"Attention-dependent reductions in response variability: underlying mechanisms"

 Presented by

John H. Reynolds, Ph.D.
Department of Neurobiology
Salk Institute for Biological Studies

Reception with Refreshments at 3:30 AM

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Abstract: For the past thirty years, research on the neural mechanisms of attention has focused primarily on the modulation of mean firing rate.  Recently, we have found that attention also reduces neuronal response variability (Mitchell, Sundberg & Reynolds, 2007), and that some of the variability that is reduced is shared across neurons (Mitchell, Sundberg & Reynolds, 2009; Cohen & Maunsell, 2009).  We find that reductions in low frequency correlated variability accounts for 80% of attention-dependent improvement in the signal-to-noise ratio of the pooled neuronal signal, with the remaining 20% attributable to changes in mean firing rate.  Therefore, in order to understand the neural mechanisms of attention, one must understand (1) what gives rise to response variability and (2) how attention reduces this variability.  We have developed a conductance-based model to account for both the emergence of variability and its reduction by attention. In addition to accounting for reductions in variability, this model also accounts for our recent finding that attention reduces the tendency of neurons to fire action potentials in bursts.  Further, it makes the testable prediction that attention will reduce the amplitude of the neuronal action potential, a prediction that we find holds true in macaque Area V4.

Sponsored by: Center for Perceptual Systems Seminar Series

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