TY - JOUR T1 - Spatiotemporal Tuning of Rapid Interactions between Visual-Motion Analysis and Reaching Movement JF - The Journal of Neuroscience JO - J. Neurosci. SP - 5301 LP - 5308 DO - 10.1523/JNEUROSCI.0340-06.2006 VL - 26 IS - 20 AU - Hiroaki Gomi AU - Naotoshi Abekawa AU - Shin’ya Nishida Y1 - 2006/05/17 UR - http://www.jneurosci.org/content/26/20/5301.abstract N2 - In addition to the goal-directed preplanned control, which strongly governs reaching movements, another type of control mechanism is suggested by recent findings that arm movements are rapidly entrained by surrounding visual motion. It remains, however, controversial whether this rapid manual response is generated in a goal-oriented manner similarly to preplanned control or is reflexively and directly induced by visual motion. To investigate the sensorimotor process underlying rapid manual responses induced by large-field visual motion, we examined the effects of contrast and spatiotemporal frequency of the visual-motion stimulus. The manual response amplitude increased steeply with image contrast up to 10% and leveled off thereafter. Regardless of the spatial frequency, the response amplitude increased almost proportionally to the logarithm of stimulus speed until the temporal frequency reached 15–20 Hz and then fell off. The maximum response was obtained at the lowest spatial frequency we examined (0.05 cycles/°). These stimulus specificities are surprisingly similar to those of the reflexive ocular-following response induced by visual motion, although there is no direct motor entrainment from the ocular to manual responses. In addition, the spatiotemporal tuning is clearly different from that of perceptual effects caused by visual motion. These comparisons suggest that the rapid manual response is generated by a reflexive sensorimotor mechanism. This mechanism shares a distinctive visual-motion processing stage with the reflexive control for other motor systems yet is distinct from visual-motion perception. ER -