The rubro-olivo-cerebellar teaching circuit.

The hypothesis proposes a neural teaching circuit, and invokes the parvocellular Red Nucleus as the key nucleus in that circuit acting on the inferior olivary nucleus to maintain the efficiency of motor learning in primates, while acknowledging the inferior olive to be the key nucleus by which learning instructions go to Purkinje cells in the cerebellar cortex. Anatomical, physiological and pathological data is reviewed in an attempt to attribute a function to the evasive parvocellular Red Nucleus.