Random innervation of cerebellar Purkinje cells as a substrate for diverse representational learning

Although the cerebellar microcircuit is among the most well-characterized systems for studying neural computation, recent connectomic analysis highlight deviations from canonical models, raising fundamental questions about connectivity, function, and learning in the system. A key feature of the circuit is the convergence of a vast number of parallel fibers (PFs) onto Purkinje cells (PCs). Prevailing models of cerebellar computation assume all-to-all connectivity at this intersection, whereby a single PC 'samples' from all PFs. However, experimental evidence suggests that each PC is innervated by only a subset of accessible PFs. This partial sampling creates differential connectivity that may