Asymmetric Transfer of Visuomotor Learning between Discrete and Rhythmic Movements

Abstract

As long as we only focus on kinematics, rhythmic movement appears to be a concatenation of discrete movements or discrete movement appears to be a truncated rhythmic movement. However, whether or not the neural control processes of discrete and rhythmic movements are distinct has not yet been clearly understood. Here, we address this issue by examining the motor learning transfer between these two types of movements testing the hypothesis that distinct neural control processes should lead to distinct motor learning and transfer. First, we found that the adaptation to an altered visuomotor condition was almost fully transferred from the discrete out-andback movements to the rhythmic out-and-back movements; however, the transfer from the rhythmic to discrete movements was very small. Second, every time a new set of rhythmic movements was started, a considerable amount of movement error reappeared in the first and the following several cycles although the error converged to a small level by the end of each set. Last, we observed that when the discrete movement training was performed with intertrial intervals longer than 4 s, a significantly larger error appeared, specifically for the second and third cycles of the subsequent rhythmic movements, despite a seemingly full transfer to the first cycle. These results provide strong behavioral evidence that different neuronal control processes are involved in the two types of movements and that discrete control processes contribute to the generation of the first cycle of the rhythmic movement.

Formation of model-free motor memories during motor adaptation depends on perturbation schedule

“…In an experiment where left-hand movements, which were perturbed by a force field, were either accompanied by a nonperturbed movement of the right hand (bimanual condition) or not (unimanual condition), Nozaki and col-leagues (2006) found limited transfer of learning between these two conditions. Limited transfer of learning was also observed between rhythmic and discrete movements (Ikegami et al 2010). In addition, distinct motor plans or distinct tools are also associated with limited interference between two opposing perturbations (Cothros et al 2009;Hirashima and Nozaki 2012).…”

Intermittent Visual Feedback Can Boost Motor Learning of Rhythmic Movements: Evidence for Error Feedback Beyond Cycles

“…We have previously reported that the performance of motor adaptation to a visual rotation deteriorated with regard to rhythmic reaching movements, compared with a discrete reaching movement with ITIs of Ͼ1 s with respect to the rate of error reduction and converged plateau level (Ikegami et al, 2010). This implies that the impaired motor learning for rhythmic movement may be attributed to the degraded temporal association between the motor commands and the resultant movement errors.…”

“…3). Longer training with CON condition would not decrease the error to this level, because it remained unchanged by the extensive training with Ͼ1000 movement cycles (Ikegami et al, 2010). Notably, previous psychological studies (Winstein and Schmidt, 1990;Wulf and Shea, 2002) have demonstrated the beneficial effects of a reduced frequency in error feedback on motor learning.…”

“…Indeed, we have shown that adaptation of out-and-back movements to a visual rotation was worse when it was performed continuously (i.e., rhythmic movement) than discretely; the convergence of movement error was slower, and the final plateau level of movement error was greater (Ikegami et al, 2010).…”

Interaction between telencephalic signals and respiratory dynamics in songbirds

“…Squares correspond to naturally occurring respiratory patterns (open, quiet breathing; filled, song); triangles correspond to inspirations following stimulation (open, quiet breathing before and after stimulations; filled, minibreath-like inspirations during and immediately after stimulation). be different, possibly paralleling differences in the generation of discrete and rhythmic movements in mammals (Ikegami et al 2010;Schaal et al 2004). Lack of stable, sustained rhythms in the song of the zebra finch may require more directive input than the driving of intrinsic rhythms emerging from the nonlinear network in the canary.…”