Perception of biological motion is a fundamental property of the human visual system. It is as yet unclear which role the cerebellum plays with respect to the perceptual analysis of biological motion represented as point-light displays. Imaging studies investigating biological motion perception revealed inconsistent results concerning cerebellar contribution. The present study aims to explore the role of the cerebellum in the perception of biological motion by testing the performance of biological motion perception in patients suffering from circumscribed cerebellar lesions and comparing their performance with an age-matched control group.

Perceptual performance was investigated in an experimental task testing the threshold to detect biological motion masked by scrambled motion and a control task testing detection of motion direction of coherent motion masked by random noise. Results show clear evidence for a differential contribution of the cerebellum to the perceptual analysis of coherent motion compared to biological motion. Whereas the ability to detect biological motion masked by scrambled motion was unaffected in the patient group, their ability to discriminate direction of coherent motion in random noise was substantially affected. We conclude that intact cerebellar function is not a prerequisite for a preserved ability to detect biological motion. Since the dorsal motion pathway as well as the ventral form pathway contribute to the visual perception of biological motion, the question remains open, whether cerebellar dysfunction affecting the dorsal pathway is compensated for by the not affected ventral pathway or whether perceptual analysis of biological motion is performed completely without cerebellar contribution.