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Transfer of adaptation from visually guided saccades to averaging saccades elicited by double visual targets
Author(s) -
Alahyane Nadia,
Koene Ansgar,
Pélisson Denis
Publication year - 2004
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2004.03536.x
Subject(s) - saccade , adaptation (eye) , eye movement , encoding (memory) , computer science , neuroscience , psychology , artificial intelligence , communication
The adaptive mechanisms that control the amplitude of visually guided saccades (VGS) are only partially elucidated. In this study, we investigated, in six human subjects, the transfer of VGS adaptation to averaging saccades elicited by the simultaneous presentation of two visual targets. The generation of averaging saccades requires the transformation of two representations encoding the desired eye displacement toward each of the two targets into a single representation encoding the averaging saccade (averaging programming site). We aimed to evaluate whether VGS adaptation acts upstream (hypothesis 1) or at/below (hypothesis 2) the level of averaging saccades programming. Using the double‐step target paradigm, we simultaneously induced a backward adaptation of 17.5° horizontal VGS and a forward adaptation of 17.5° oblique VGS performed along the ± 40° directions relative to the azimuth. We measured the effects of this dual adaptation protocol on averaging saccades triggered by two simultaneous targets located at 17.5° along the ± 40° directions. To increase the yield of averaging saccades, we instructed the subjects to move their eyes as fast as possible to an intermediate position between the two targets. We found that the amplitude of averaging saccades was smaller after VGS adaptation than before and differed significantly from that predicted by hypothesis 1, but not by hypothesis 2, with an adaptation transfer of 50%. These findings indicate that VGS adaptation largely occurs at/below the averaging saccade programming site. Based on current knowledge of the neural substrate of averaging saccades, we suggest that VGS adaptation mainly acts at the level of the superior colliculus or downstream.