HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) A corrigendum has been published All Versions of this Article: 98/5/2580    most recent 00522.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Cohen, J. Y. Articles by Rossi, A. F. Search for Related Content PubMed PubMed Citation Articles by Cohen, J. Y. Articles by Rossi, A. F.

Difficulty of Visual Search Modulates Neuronal Interactions and Response Variability in the Frontal Eye Field

¹Vanderbilt Brain Institute, ²Department of Psychology, ³Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, Tennessee, and ⁴Vanderbilt Vision Research Center, Nashville, Tennessee

Submitted 9 May 2007; accepted in final form 6 September 2007

The frontal eye field (FEF) is involved in selecting visual targets for eye movements. To understand how populations of FEF neurons interact during target selection, we recorded activity from multiple neurons simultaneously while macaques performed two versions of a visual search task. We used a multivariate analysis in a point process statistical framework to estimate the instantaneous firing rate and compare interactions among neurons between tasks. We found that FEF neurons were engaged in more interactions during easier visual search tasks compared with harder search tasks. In particular, eye movement–related neurons were involved in more interactions than visual-related neurons. In addition, our analysis revealed a decrease in the variability of spiking activity in the FEF beginning 100 ms before saccade onset. The minimum in response variability occurred 20 ms earlier for the easier search task compared with the harder one. This difference is positively correlated with the difference in saccade reaction times for the two tasks. These findings show that a multivariate analysis can provide a measure of neuronal interactions and characterize the spiking activity of FEF neurons in the context of a population of neurons.