The motor system in simple reaction time experiments

In this paper evidence is presented that the variability of the motor system does not play an important role in the variability of simple reaction time. Many studies refer to this fact which, however, seems contradictory to electrophysiological data. A model is proposed for the operation of the motor system in simple reaction time experiments which consistently links single cell neuronal activity with electromyographic activity and with response time. It appears that the motor system subserving simple reactions consists of many elements which once triggered produce a mechanical response well defined in time despite the fact that the elements themselves show a rather large time jitter.