Online corrective responses following target jump in altered gravitoinertial force field point to nested feedforward and feedback control

Abstract

Studies on goal-directed arm movements have shown a close link between feedforward and feedback control in protocols where both planning and online control processes faced a similar type of perturbation, either mechanical or visual. This particular context might have facilitated the use of an adapted internal model by feedforward and feedback control. Here we considered this link in a context where after feedforward control was adapted through proprioception-based processes, feedback control was tested under visual perturbation. We analyzed the response of the reaching hand to target displacements following adaptation to an altered force field induced by rotating participants at constant velocity. Reaching corrections were assessed through variables related to the accuracy (lateral and longitudinal endpoint errors) and kinematics (movement time, peak velocity) of the corrective movements. The electromyographic activity of different arm muscles (pectoralis, deltoid, biceps and triceps brachii) was analyzed. Statistical analyses revealed that accuracy and kinematics of corrective movements were strikingly alike between normal and altered gravitoinertial force fields. However, pectoralis and biceps muscle activities recorded during corrective movements were significantly modified to counteract the effect of rotation-induced Coriolis and centrifugal forces on the arm. Remarkably, feedback control was functional from the very first time participants encountered a target jump in the altered force field. Overall, the present results demonstrate that feedforward control enables immediate functional feedback control even when applied to distinct sensorimotor processes.

Hypergravity is more challenging than microgravity for the human sensorimotor system

“…On a similar task, Bringoux et al (2020) reported a perfectly scaled feedback response when the target moved unexpectedly at movement onset. These findings also support those already observed with robotic devices (Cluff and Scott 2013;Crevecoeur and Scott 2013;Kimura and Gomi 2009) or modified gravitational forced fields (Bringoux et al 2020;Chomienne et al 2021) and confirm the strong link between feedforward and feedback control.…”

“…Another issue raised in this study refers to the CNS ability to deal with unexpected and sudden perturbations in altered gravity. On Earth, the flexibility of sensorimotor control mechanisms is well known (Gomi 2008; Sarlegna and Mutha 2015, for reviews), as for instance motor commands can be rapidly adjusted during movement execution in response to a small mechanical (Cluff and Scott 2013;Crevecoeur and Scott 2013;Kimura and Gomi 2009) or visual (Chomienne et al 2021;Hayashi et al 2016;Saijo and Gomi 2010;Telgen et al 2014) perturbation. In microgravity, Bringoux et al (2020) reported that an unpredictable target jump triggered at arm movement onset did not affect final endpoint accuracy during a whole-body reaching task,.…”

Asymmetrical transfer of adaptation between reaching and tracking: implications for feedforward and feedback processes

“…To address this issue a neat way is to introduce unexpected target jumps following the adaptation phase. Although this protocol demonstrated that participants were able to trigger adequate online corrections (reflexes) following adaptation to force field [10][11][12][13][14] or to visuomotor rotation [15][16][17], contrasting results were observed following adaptation to visual feedback inversion [18][19][20]. Surprisingly, the possibility that the update of feedback mechanisms could reciprocally drive the update of feedforward mechanisms is much less documented, presumably because setting the adequate experimental conditions to address this issue is challenging.…”