Visuomotor Map Determines How Visually Guided Reaching Movements are Corrected Within and Across Trials.
When a visually guided reaching movement is unexpectedly perturbed, it is implicitly corrected in two ways: immediately after the perturbation by feedback control (online correction) and in the next movement by adjusting feedforward motor commands (offline correction or motor adaptation). Although recent studies have revealed a close relationship between feedback and feedforward controls, the nature of this relationship is not yet fully understood. Here, we show that both implicit online and offline movement corrections utilize the same visuomotor map for feedforward movement control that transforms the spatial location of visual objects into appropriate motor commands. First, we artificially distorted the visuomotor map by applying opposite visual rotations to the cursor representing the hand position while human participants reached for two different targets. This procedure implicitly altered the visuomotor map so that changes in the movement direction to the target location were more insensitive or more sensitive. Then, we examined how such visuomotor map distortion influenced online movement correction by suddenly changing the target location. The magnitude of online movement correction was altered according to the shape of the visuomotor map. We also examined offline movement correction; the aftereffect induced by visual rotation in the previous trial was modulated according to the shape of the visuomotor map. These results highlighted the importance of the visuomotor map as a foundation for implicit motor control mechanisms and the intimate relationship between feedforward control, feedback control, and motor adaptation.
Division of Physical and Health Education, Graduate School of Education, The University of Tokyo, Tokyo 113-0033, Japan; Japan Society for the Promotion of Science, Tokyo 102-8471, Japan.
Takuji
0000-0002-3875-6829
T
Hayashi
The Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada N6A 5B7; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan.
Atsushi
0000-0002-7428-3344
A
Yokoi
Center for Information and Neural Networks, National Institute of Information and Communications Technology , Suita, Osaka 565-0871, Japan.
Masaya
M
Hirashima
Division of Physical and Health Education, Graduate School of Education, The University of Tokyo , Tokyo 113-0033, Japan.
Daichi
0000-0002-1338-8337
D
Nozaki
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001132:Arm / Q000502:physiology; D001696:Biomechanical Phenomena; D025461:Feedback, Physiological; D030141:Feedback, Psychological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011601:Psychophysics; D014796:Visual Perception; D055815:Young Adult
feedback control; feedforward control; motor adaptation; reaching movement; visuomotor map