Oxyopia Abstract

Septmeber 22, 2006
Friday, 4 PM
489 Minor Hall

Michael Shadlen, MD, PhD
Professor of Physiology and Biophysics and Core Staff Scientist of the National Primate Research Center, University of Washington, and Investigator, Howard Hughes Medical Institute
Host: Ralph Freeman

Title

A Neural Mechanism for Decision-Making

Abstract

With little sophistication, the spike rates from sensory neurons can be used to approximate useful statistics for decision-making. In the context of deciding between two sensory hypotheses, a simple difference in spike rate between sensory neurons with opposite selectivity is proportional to the logarithm of a likelihood ratio in favor of one sensory interpretation over another. I will describe neural recording and stimulation experiments from the alert monkey that demonstrate that the brain uses such a difference to make decisions about the direction of motion in a 2-alternative direction discrimination task. The accumulation of this difference to threshold explains the speed and accuracy of simple decisions. Interestingly, the neural computations that underlie such decision process were anticipated during WWII by Alan Turing and Abraham Wald. Turing applied this tool to break the German navyâs Enigma cipher, while Wald invented the field of sequential analysis. In addition to mathematical elegance and winning wars, our experiments suggest that this computational strategy may lie at the core of higher brain function.

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