ABSTRACT
Various lines of evidence implicate the cerebellum as one node in a network of neural regions engaged in controlled cognitive processes. Characterizing the functional role of the cerebellum within this network, and in cognition more broadly, has proven elusive. Motivated by models of how the cerebellum helps coordinate movement, we propose that the cerebellum contributes to cognitive tasks that involve the transformation of mental representations along a continuous dimension. To test this hypothesis, we compared tasks that entail the continuous transformation of a single visual representation or discrete computations over a set of visual representations. We predicted that individuals with cerebellar degeneration (CD) would be selectively impaired on the former. Consistent with this prediction, two independent CD groups were impaired on a mental rotation task, with the estimated rate of rotation slower than that observed in matched controls. In contrast, the rate required to perform an iterative search through a series of representations in visual (Experiment 1) or visuospatial (Experiment 2) working memory was comparable in the CD and control groups. This dissociation highlights a potential computational constraint on the role of the cerebellum in cognition, setting the stage for future work examining cerebellar contributions to a wider range of behaviors.
