Neurophysiology of Brain Circuits Team, Institut de Biologie de l'École Normale Supérieure, Inserm U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
Neurophysiology of Brain Circuits Team, Institut de Biologie de l'École Normale Supérieure, Inserm U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
Neurophysiology of Brain Circuits Team, Institut de Biologie de l'École Normale Supérieure, Inserm U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
Head movements are primarily sensed in a reference frame tied to the head, yet they are used to calculate self-orientation relative to the world. This requires to re-encode head kinematic signals into a reference frame anchored to earth-centered landmarks such as gravity, through computations whose neuronal substrate remains to be determined. Here, we studied the encoding of self-generated head movements in the rat caudal cerebellar vermis, an area essential for graviceptive functions. We found that, contrarily to peripheral vestibular inputs, most Purkinje cells exhibited a mixed sensitivity to head rotational and gravitational information and were differentially modulated by active and passive movements. In a subpopulation of cells, this mixed sensitivity underlay a tuning to rotations about an axis defined relative to gravity. Therefore, we show that the caudal vermis hosts a re-encoded, gravitationally polarized representation of self-generated head kinematics in freely moving rats.
