Biological motion influences the visuomotor transformation pursuit eye movements

Humans are very sensitive to the presence of other living persons or animals in their surrounding Human actions can readily be perceived even in a noisy environment We recently demonstrated that biological motion which schematically represents human motion influences smooth pursuit eye movements during the initiation period (Orban de Xivry Coppe Lefevre & Missal 2010) This smooth pursuit response is driven both by a visuomotor pathway which transforms retinal Inputs into motor commands, and by a memory pathway which is directly related to the predictive properties of smooth pursuit To date it is unknown which of these pathways is influenced by biological motion In the present study we first use a theoretical model to demonstrate that an influence of biological motion on the visuomotor and memory pathways might both explain its influence on smooth pursuit initiation In light of this model we made theoretical predictions of the possible influence of biological motion on smooth pursuit during and after the transient blanking of the stimulus These qualitative predictions were then compared with recordings of eye movements acquired before during and after the transient blanking of the stimulus The absence of difference in smooth pursuit eye movements during blanking of the stimuli and the stronger visually guided smooth pursuit reacceleration after reappearance of the biological motion stimuli in comparison with control stimuli suggests that biological motion influences the visuomotor pathway but not the memory pathway (C) 2010 Elsevier Ltd All rights reserved