Schedule of Events | Symposia

Motor Planning in Posterior Parietal Cortex is Critical in Motor Learning

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Hidetaka Hibino¹ (h.hibino@northeastern.edu), Anna Akbas², Bailey Uitz¹, Jacob Kogan¹, Terrence Murphy³, Mathew Yarossi¹, Robert Sainburg³, Eugene Tunik¹; ¹Northeastern University, ²Academy of Physical Education in Katowice, ³Pennsylvania State Univeristy

While posterior parietal cortex (PPC), which is involved in movement planning and online correction, is a critical cortical area in motor learning, the parietal processes that govern motor learning are poorly understood. We causally investigated the PPC involvement in motor adaptation by delivering double-pulse transcranial magnetic stimulation (TMS) to the left PPC at the movement planning and the online correction phases during a visuomotor rotation adaptation (VMRA) task. Right-handed participants (n=42) were randomly assigned to No TMS, Prior-To-Movement (Early) TMS, or Later-In-Movement (Late) TMS. Participants completed four blocks in which they reached to pseudorandomly presented targets (8 locations) 12cm away from a fixed central point: Left-Arm Baseline, Right-Arm Baseline, Right-Arm VMRA, and Left-Arm Interlimb Transfer (Transfer). The visually displayed and actual hand motion were matched during the Baselines, whereas the visual feedback of the hand deviated from the actual movement direction of the hand by 30 degrees during the VMRA and Transfer. During the Right-Arm Baseline and Right-Arm VMRA, Early TMS and Late TMS received TMS 50ms after target visualization and when the hand was 8cm away from the starting point, respectively. During the Baselines, the reaching accuracy was comparable between groups. During the early stage of VMRA, the magnitude of reaching errors was lower in Early TMS, but not in Late TMS, compared to No TMS groups (p<0.05). This study provides supportive evidence for a causal role of the left PPC in planning for motor learning as seen by enhanced correction of reaching accuracy in Early TMS.

Topic Area: PERCEPTION & ACTION: Motor control