Abstract
It has been reported that a brief movement of a target during fixation elicited larger eye movement when primates were anticipating future smooth pursuit than when they were not, suggesting that the gain of visuomotor transmission was increased in association with the preparation for future tracking. Here, in order to investigate how the expectation for future tracking affects our preparation for smooth pursuit, we observed human eye movements elicited by a brief movement of a target when the probability to be required pursuit (target motion probability) was 0, 0.25, 0.5, 0.75, and 1. We found that the response to a brief target movement was continuously increased as the probability increased. This result suggests that the pursuit system determines the gain before the start of pursuit in accordance with the anticipated future need for tracking. We also showed that the relationship between the gain and the target motion probability could be derived from minimization of the trialβbyβtrial prediction error, suggesting that the preparatory gain was determined based on the leastβsquares optimization. Β© 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 1β9, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20677 Copyright Β© 2004 Wiley Periodicals, Inc.