Adaptation to Visuomotor Rotation and Force Field Perturbation Is Correlated to Different Brain Areas in Patients With Cerebellar Degeneration

TLDR

The cerebellum is essential for motor learning, but it is unclear whether the same cerebellar regions support adaptation to kinematic versus dynamic errors. This study examined arm movements during a visuomotor rotation and a force‑field perturbation in 14 patients with cerebellar degeneration and 14 matched controls. Magnetic‑resonance imaging was used to quantify volumes of medial, intermediate, and lateral zones in the anterior and posterior lobes to identify structures underlying each task. Patients showed deficits in both tasks, with no cross‑task correlation, and atrophy of distinct cerebellar zones—anterior lobe zones for the force field and posterior lobe intermediate zone for the visuomotor rotation—indicating independent processing.

Abstract

Although it is widely agreed that the cerebellum is necessary for learning and consolidation of new motor tasks, it is not known whether adaptation to kinematic and dynamic errors is processed by the same cerebellar areas or whether different parts play a decisive role. We investigated arm movements in a visuomotor (VM) rotation and a force field (FF) perturbation task in 14 participants with cerebellar degeneration and 14 age- and gender-matched controls. Magnetic resonance images were used to calculate the volume of cerebellar areas (medial, intermediate, and lateral zones of the anterior and posterior lobes) and to identify cerebellar structure important for the two tasks. Corroborating previous studies, cerebellar participants showed deficits in adaptation to both tasks compared with controls ( P < 0.001). However, it was not possible to draw conclusions from the performance in one task on the performance in the other task because an individual participant could show severe impairment in one task and perform relatively well in the other (ρ = 0.1; P = 0.73). We found that atrophy of distinct cerebellar areas correlated with impairment in different tasks. Whereas atrophy of the intermediate and lateral zone of the anterior lobe correlated with impairment in the FF task (ρ = 0.72, 0.70; P = 0.003, 0.005, respectively), atrophy of the intermediate zone of the posterior lobe correlated with adaptation deficits in the VM task (ρ = 0.64; P = 0.015). Our results suggest that adaptation to the different tasks is processed independently and relies on different cerebellar structures.