Sensory Mapping in Zebrin-positive Modules in the Cerebellum

The regularity of the cellular organization of the cerebellar cortex has long been considered as a sign of structural homogeneity, where all parts perform a similar type of information processing on different types of data streams. In contrast to the structural homogeneity of the neuronal network, the inputs to the cerebellar cortex are not homogeneously distributed. Instead, they project to distinct parasagittal zones based on their origin. The zones can be observed in the patterning of the climbing fiber projections from the inferior olive to the cerebellar cortex and in that of the projections from the cerebellar cortex to the nuclei. The parasagittal zones can be recognized, apart from by its connections, by their alternating expression patterns of the protein “zebrin II”. The parasagittal zones can be subdivided into smaller “microbands” that could function as synchronized ensembles. For this thesis, we first investigated the basic electrophysiological properties of Purkinje cells in parasagittal zones with different zebrin-identities. Then we zoomed in to single cell resolution to observe the responses of Purkinje cells to different sensory inputs via climbing fiber projections.