2008 Volume 9 Issue 1 Pages 20-45
Cortical field potentials were recorded by cortical surface and depth electrodes implanted in various cerebral cortices in monkeys during self-paced simple movements of hand, mouth, neck and trunk, and complex movements of neck and trunk. The potentials were also recorded while the monkeys learned simple visuo-, audio- and somatosenso-initiated hand movements, and complex visuo-, audio- and somatosenso-initiated hand movements with discrimination of color, tone and texture etc. The potentials were analyzed in connection with cognitive functions. It was revealed in which cortical area any cognitive function was mainly localized in the frontal and parietal lobes. Motor and spatial discrimination functions were found to be disturbed by cerebellar hemispherectomy. After cerebellar hemispherectomy, substitute motor functions for the somatosensory and posterior parietal cortices of lowered motor functions of the motor cortex appeared, and increase of the substitute functions was discussed in connection with rehabilitation therapy of physical exercise etc.
Effects of physical exercise on cognitive functions were further studied using eight monkeys. Two of them were trained for 3-7 months with a newly developed machine for monkey hindlimb movement (exercise group). While the monkeys in the exercise group learned simple audio- and visuo-initiated hand movements after the physical exercise, cortical field potentials and reaction times were recorded and then analyzed. The analyzed results were compared with those in six monkeys without the physical exercise (no-exercise group). It was suggested that physical exercise improved cognitive functions in monkeys.
