Specialized outputs and behavioral contributions of Purkinje cell subtypes

Abstract

Purkinje cells (PCs), the sole outputs of the cerebellar cortex, transform granule cell firing patterns into appropriate outputs to drive learning and behavior. Two major PC classes (typically defined by Aldoc expression) can be further subdivided into nine molecularly distinct PC subtypes, suggesting that each subtype might be specialized for distinct categories of cerebellar processing. This has been difficult to test due to limited tools to target PC subtypes. We therefore developed intersectional tools to target PC subtypes, specifically Kcng4+ PCs (primarily Aldoc-) and Gpr176+ PCs (Aldoc1). We mapped their distributions within the cerebellar cortex and quantitatively characterized their outputs onto different types of cerebellar nuclei (CbN) neurons. Although projections by PC subtypes defined by Kcng4 and Gpr176 are regionally segregated within the CbN, each PC subtype synapses onto many types of CbN neurons, and individual CbN neurons often receive convergent inputs from multiple PC subtypes. We also selectively silenced PC subtype outputs and found that silencing Kcng4+ PC outputs impaired motor behaviors while sparing emotional and social behaviors, whereas silencing Gpr176+ PC outputs selectively increased exploratory behavior and reduced anxiety without affecting motor and social behaviors. These findings demonstrate that molecularly defined PC subtypes differentially regulate specific behaviors and establish a versatile framework for uncovering how cerebellar circuits are specialized to control diverse behaviors.