ABSTRACT
The conceptual link between muscles and motivation has now been forged. In analyzing the hierarchical arrangement of the mechanisms of sensorimotor coordination I noted the central importance of selective potentiation, which permits a unit of coordination to operate only when its operation will be functional. If we allow for a moment functional units to be personified as actors, then we may say that potentiation and depotentiation determine who may act and when, in order that the animal may produce a show and not a circus. Whether a potentiated actor actually performs depends upon whether the stage contains the props for his act and/or upon whether the actors already on stage produce his entrance cue.
