Short-term reorganization of the rat somatosensory cortex following hypodynamia-hypokinesia

This study was performed to determine if hypodynamia-hypokinesia (HH) could induce a reorganization of the rat somatosensory cortex. The cortical hind paw representation was determined by stimulating the limb and recording mul ti-unit cortical activity. The size of the cutaneous receptive fields was a lso measured. After 14 days of HH, the size of the cortical hindpaw represe ntation was decreased. The proportion of small cutaneous receptive fields d ecreased while the large ones increased. After 7 days of HH, no change in t he two studied parameters was noticed in five animals. In the other rats, a number of sites unresponsive to cutaneous stimulation or with high thresho lds was observed. This study provides evidence of a plasticity of the somat osensory cortex induced by a situation that reduces both sensory and motor functions. The cortical reorganization occurs in two stages. (C) 1999 Elsev ier Science Ireland Ltd. All rights reserved.