Exercise induces angiogenesis but does not alter movement representations within rat motor cortex

The effects of exercise on the topography of movement representations and blood vessel density within the rat forelimb motor cortex was examined. Adult male rats were allocated to either a Voluntary eXercise (VX) or Inactive Condition (IC). VX animals were housed for 30 days with unlimited access to running wheels while IC animals were housed in standard laboratory cages. VX animals exhibited a progressive increase in the distance traveled per day and ran an average of 58.3 km across the 30-day training period. Microelectrode stimulation was used to derive high resolution maps of the forelimb representations within the motor cortex of animals from both conditions. No significant differences in the area of either distal (wrist/digit) or proximal (elbow/shoulder) movement representations were found between VX and IC animals. However, VX animals did have a significantly greater density of blood vessels within layer V of the forelimb motor cortex. These results demonstrate that increases in forelimb motor activity sufficient to induce cortical angiogenesis does not alter the topography of forelimb movement representations within forelimb motor cortex.