This project was designed to explore mechanisms of information processing occurring within cortical columns in the somatic sensorimotor cortex and to determine how this relates to limb movement. Extracellular, single neuron recording techniques in awake, behaving monkeys were used to study neural mechanisms involved in the cerebral motor control. Neuronal responses to cerebellar stimulation, obtained via chronically implanted electrodes in the brachium conjunctivum, were recorded using microelectrodes in the primary motor cortex. Stimulation of the cerebellum was delivered during various phases of forelimb movement, which consisted of alternation between two horizontal levers controlled by light cues indicating to the monkey when to move. A computer program was developed to control the light cues given to the monkeys indicating when to move, and to deliver the cerebellar stimulation at specific times during the forelimb movement. Input-output relations of the cortical columns were then studied by investigating the effects cerebellar afferents to the cerebrum on neurons in the different cortical layers.