Attenuation of somatosensory evoked potentials immediately following rapid reaction movement

We investigated the changes in the somatosensory evoked potentials (SEPs) and particularly which components of the SEPs altered immediately after rapid reaction movements. N20, P23, N35, and P45 components measured over the scalp were all attenuated except for the P45 component measured at CZ. Particularly, the N20 and P23 components were markedly attenuated at both C3' and CZ immediately following rapid reaction movements. N18 and N20 components are thought to represent thalamocortical and primary sensory cortex activities. Therefore, the present results suggest that following rapid reaction movements, the thalamocortical and primary sensory activities are significantly attenuated. Moreover, following rapid reaction movements, the onset of EMG activity preceded the afferent discharge of the muscle spindle. Therefore, it may be concluded that central factors were principally responsible for the attenuation of the SEPs immediately following rapid reaction movements.