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) All Versions of this Article: 99/5/2194    most recent 01271.2007v1 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 Web of Science 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 Google Scholar Google Scholar Articles by Thura, D. Articles by Meunier, M. Search for Related Content PubMed PubMed Citation Articles by Thura, D. Articles by Meunier, M.

Hand Position Affects Saccadic Reaction Times in Monkeys and Humans

Institut de Neurosciences Cognitives de la Méditerranée, Unité Mixte de Recherche 6193, Centre National de la Recherche Scientifique and Aix-Marseille Université, Marseille, France

Submitted 20 November 2007; accepted in final form 9 March 2008

In daily life, activities requiring the hand and eye to work separately are as frequent as activities requiring tight eye–hand coordination, and we effortlessly switch from one type of activity to the other. Such flexibility is unlikely to be achieved without each effector "knowing" where the other one is at all times, even when it is static. Here, we provide behavioral evidence that the mere position of the static hand affects one eye movement parameter: saccadic reaction time. Two monkeys were trained and 11 humans instructed to perform nondelayed or delayed visually guided saccades to either a right or a left target while holding their hand at a location either near or far from the eye target. From trial to trial, target locations and hand positions varied pseudorandomly. Subjects were tested both when they could and when they could not see their hand. The main findings are 1) the presence of the static hand in the workspace did affect saccade initiation; 2) this interaction persisted when the hand was invisible; 3) it was strongly influenced by the delay duration: hand–target proximity retarded immediate saccades, whereas it could hasten delayed saccades; and 4) this held true both for humans and for each of the two monkeys. We propose that both visual and nonvisual hand position signals are used by the primates' oculomotor system for the planning and execution of saccades, and that this may result in a hand–eye competition for spatial attentional resources that explains the delay-dependent reversal observed.

This article has been cited by other articles:

				C. Grefkes, L. E. Wang, S. B. Eickhoff, and G. R. Fink Noradrenergic Modulation of Cortical Networks Engaged in Visuomotor Processing Cereb Cortex, August 17, 2009; (2009) bhp144v1. [Abstract] [Full Text] [PDF]