Basic cerebellar events relating sensorimotor adaptation--structural analysis on extracellular records of Purkinje...

The heterosynaptic facilitation or suppression of synaptic efficacy between parallel fibers and the dendritic spines of Purkinje cells (PCs) in the cerebellar cortex has been for decades the basic idea of sensorimotor adaptation. Great efforts in order to get direct evidence failed, or were not accepted as direct proofs. A new facility was introduced with the structural analysis of intradendritic records of the PC. These records reveal a generally double (rarely single, triple or quadruple) rhythmic pattern of small spikes, which are proposed to be prespikes of dendritic origin. Moreover, they may take their origin at functionally separated dendritic compartments resulting in a nonlinear, phase-sensitive integrative process, performed by the compound spike generating mechanism of the cerebellar PC.