Sensory, motor and cognitive aspects of cerebellar control over the whisker system

Mice rely on whiskers to orient themselves in the environment and to determine position, size and texture of objects. They have large whiskers that can be moved rhythmically. In line with its behav ioral importance, a substantial pan of the brain is devoted to the whisker system. Most attention has been paid to ascending trigemino-thalamo-cortical pathways and descending pathways from motor cortex to brainstem, but many other brain regions are also part of the whisker system: I will discuss sensory, motor and cognitive roles of the cerebellum, a crucial organ for sensorimotor control. The cerebellum receives strong whisker input, directly via the brainstem and indirectly via the cerebral cortex. The spatial and temporal organization of whisker input to the cerebellum will be discussed as well as the cerebellar impact on whisker movement. This will be shown in electrophysiological recordings in awake mice. Finally, we demonstrate that mutant mice specifically impaired in synaptic and intrinsic plasticity of cerebellar Purkinje cells have severe problems learning a whisker based object localization task, showing that the cerebellum is also important for cognitive aspects of behavior.