RESUMEN
Under the different load of training stimulating, the changes in center nervous system of rat were observed.This experimental training intensities included normal -load and over-load using a swimming pool with circular water flow in order to investigate the effects on the neuron size and the density of dendritic spine of the large pyramidal cells in layer Ⅴ in motor areas of cerebral cortex.This study lead to the following conclusions:the size of nucleus and nucleolus and the density of spines of apical dendrites, insidal dendrites and basal dendrites of large pyramidal cells in layer Ⅴ in motor areas of cerebral cortex of normal-load and over-load group were higher than those of control group.It improve the capacity of brain in information processing.