Effects of cooling the prefrontal and prestriate cortex upon visually initiated hand movements in the monkey

Local cooling of the prefrontal and prestriate cortex was performed in a monkey which was trained for visually initiated reaction-time hand movement, and effects of the cooling were examined by observing changes of the movement and of field potentials that were recorded with chronically implanted electrodes in various areas of the cerebral cortex. Cooling of the inferior arcuate areas and its rostral extension ('prearcuate' area) in the bilateral hemispheres made reaction times longer and more variable than the control state, and it depressed the cerebellar-mediated potential in the forelimb motor cortex. Cooling of the prestriate cortex induced effects similar to, but weaker than those of the prearcuate area. However, simultaneous cooling of the prearcuate and prestriate areas added considerable influences to the sole cooling of the prearcuate area. In the monkey well-trained for visually initiated conditioned movements, the prearcuate area may be assumed to be center for the sending of motor commands to the motor cortex through the cerebellum and thalamus, and the prestriate area may have a similar albeit weak influence.