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

J Neurophysiol 97: 795-805, 2007. First published November 15, 2006; doi:10.1152/jn.00652.2006
0022-3077/07 $8.00

This Article Free upon publication Full Text Full Text (PDF) All Versions of this Article: 97/1/795    most recent 00652.2006v1 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 PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Ludwig, C. J. H. Articles by Gilchrist, I. D. Search for Related Content PubMed PubMed Citation Articles by Ludwig, C. J. H. Articles by Gilchrist, I. D.

A Population Coding Account for Systematic Variation in Saccadic Dead Time

Department of Experimental Psychology, University of Bristol, Bristol, United Kingdom

Submitted 22 June 2006; accepted in final form 9 November 2006

During movement programming, there is a point in time at which the movement system is committed to executing an action with certain parameters even though new information may render this action obsolete. For saccades programmed to a visual target this period is termed the dead time. Using a double-step paradigm, we examined potential variability in the dead time with variations in overall saccade latency and spatiotemporal configuration of two sequential targets. In experiment 1, we varied overall saccade latency by manipulating the presence or absence of a central fixation point. Despite a large and robust gap effect, decreasing the saccade latency in this way did not alter the dead time. In experiment 2, we varied the separation between the two targets. The dead time increased with separation up to a point and then leveled off. A stochastic accumulator model of the oculomotor decision mechanism accounts comprehensively for our findings. The model predicts a gap effect through changes in baseline activity without producing variations in the dead time. Variations in dead time with separation between the two target locations are a natural consequence of the population coding assumption in the model.

This article has been cited by other articles:

				A. Murthy, S. Ray, S. M. Shorter, J. D. Schall, and K. G. Thompson Neural Control of Visual Search by Frontal Eye Field: Effects of Unexpected Target Displacement on Visual Selection and Saccade Preparation J Neurophysiol, May 1, 2009; 101(5): 2485 - 2506. [Abstract] [Full Text] [PDF]

				K. M. Sharika, A. Ramakrishnan, and A. Murthy Control of Predictive Error Correction During a Saccadic Double-Step Task J Neurophysiol, November 1, 2008; 100(5): 2757 - 2770. [Abstract] [Full Text] [PDF]