Most contemporary theories of brain function, strongly influenced by anatomical tradition, conceive of relatively discrete localization of sensory and motor function. In conditioning, new movements constitute the responses learned to the conditioned stimulus or signal for the behavior. As a logical consequence of the assumption that sensory perception is mediated by a localized sensory system and that movement is controlled by a localized motor system, most theories of learning are "connectionistic." That is, they assume that the crucial event that takes place in learning is establishment of a pathway between the nerve cells in the brain that respond to the sensory cue and the nerve cells that control the learned response (Gerard, 1961; Hebb, 1949; Konorski, 1967). Memory of what was learned is composed of the connections newly established or facilitated during learning. Remembering consists of activity in these special pathways. Responses are determined by such activity.