Cerebellar contributions to visuomotor adaptation and motor sequence learning: an ALE meta-analysis

Abstract

Cerebellar contributions to motor learning are well-documented. For example, under some conditions, patients with cerebellar damage are impaired at visuomotor adaptation and at acquiring new action sequences. Moreover, cerebellar activation has been observed in functional MRI (fMRI) investigations of various motor learning tasks. The early phases of motor learning are cognitively demanding, relying on processes such as working memory, which have been linked to the cerebellum as well. Here, we investigated cerebellar contributions to motor learning using activation likelihood estimation (ALE) meta-analysis. This allowed us to determine, across studies and tasks, whether or not the location of cerebellar activation is constant across differing motor learning tasks, and whether or not cerebellar activation in early learning overlaps with that observed for working memory. We found that different regions of the anterior cerebellum are engaged for implicit and explicit sequence learning and visuomotor adaptation, providing additional evidence for the modularity of cerebellar function. Furthermore, we found that lobule VI of the cerebellum, which has been implicated in working memory, is activated during the early stages of explicit motor sequence learning. This provides evidence for a potential role for the cerebellum in the cognitive processing associated with motor learning. However, though lobule VI was activated across both early explicit sequence learning and working memory studies, there was no spatial overlap between these two regions. Together, our results support the idea of modularity in the formation of internal representations of new motor tasks in the cerebellum, and highlight the cognitive processing relied upon during the early phases of motor skill learning.

Keywords: cerebellum; meta-analysis; sequence learning; visuomotor adaptation; working memory.

Figure 1

(A) Schematic of a standard sequence learning task. Stimuli corresponding to buttons on a response box or keyboard are presented on a computer screen. The sequence is presented by highlighting a location, and the participant presents the corresponding button. Blocks alternate between sequence (S) presentations, and the presentation of locations in random order (R). (B) A schematic of a visuomotor adaptation task. Participants are presented with one of four targets on a computer screen, and are asked to move the cursor to the highlighted circle (top left). After several practice blocks, the feedback is rotated with respect to the participant's movement. Participants attempt to move toward the target in screen coordinates (TS), but due to the rotation subjects move toward the closed circle (TJ, target location in joystick coordinates), which is not visible to participants (top right). Direction error refers to the angle between the line from the center to the target and the line from the central to the location of the joystick at the time of peak velocity. This example is similar to what would be seen during early learning. In both panels, example data are presented. In the studies included in our meta-analysis, early and late learning were defined by the experimenters. Examples of the early and late learning phases for each task are highlighted in gray.

Figure 2

Significant ALE clusters of activation for each examined task type are presented on coronal (left) and axial (right) slices of the cerebellum. All clusters are thresholded and corrected for multiple comparisons using a false discovery rate p < 0.05. VMA, visuomotor adaptation; ISL, implicit sequence learning; ESL, explicit sequence learning; VWM, verbal working memory; SWM, spatial working memory; CRI, Crus I.

Figure 3

Significant ALE clusters of activation for the early (red) and late (blue) phases of explicit sequence learning presented on coronal (left) and axial (right) slices of the cerebellum. All clusters are thresholded and corrected for multiple comparisons using a false discovery rate p < 0.05.