THE ADAPTATION TO SENSORY INFORMATION IN THE PRODUCTION OF BIMANUAL MOVEMENT PATTERNS

Bimanual in-phase and anti-phase patterns were performed in the transv erse plane under optimal and degraded proprioceptive conditions, i.e., without and with tendon vibration. Moreover, proprioceptive informati on was changed midway into each trial to examine on-line reorganizatio n. In addition to the proprioceptive perturbation, the availability of visual information was manipulated to study to which degree sensory i nformation from different modalities interact. Movement patterns perfo rmed under identical sensory conditions were compared, i.e., the first 15 s (control) and the 15 s following a change in afferent input (tra nsfer). In the control and transfer conditions, movements with vibrati ons were less accurate than those without vibrations indicating the in fluence of optimal proprioceptive information in the calibration and r ecalibration of intrinsic bimanual movement patterns. Furthermore, pat tern stability was affected by the nature of the transfer condition. T his indicated that the degree of fluctuations in a sensory transfer si tuation depended upon the quality of the proprioceptive information ex perienced in the initial conditions. The influence of visual informati on was not without importance, although the nature of the coordination mode must be taken into account. In the control conditions, in-phase movements were less stable when vision was absent, whereas anti-phase movements were more stable when vision was not present. This observati on was made independent of the available proprioceptive information re vealing differences in visual guidance between both coordination modes . In the transfer conditions, pattern stability was similar during the vision and no-vision conditions suggesting a limited influence of vis ual information in the recalibration process.