For many years, the principal topic of interest was the functional organization of callosal fibres in the cat and their role in the coordination of bilateral motor activity. Then I became interested in the functional organization of the Dorsal Premotor Cortex of macaque monkey and in the functional proprieties of hand-related neurones in the lateral part of area F2 of the macaque monkey. In recent years I have been studying the interaction of sensory input and motor control mechanisms in the vibrissal system of the rat and the plasticity of rat motor cortex following facial nerve severing and repair. In the last three years I have examined the properties of cortical plasticity in rat motor cortex by the use of vibrissae muscle inactivation via Botulinum Toxin (BTX) injection to produce a reversible flaccid paralysis. Then I have examined the long-term effects of of BTX injection on cortical representation and muscle excitability during the period when recovery of vibrissa muscle occur. In the last year I have studied the reorganization of rat motor cortex following facial nerve severing in newborn rats.