BEHAVIOR ELICITED BY HYPOTHALAMIC STIMULATION - A PREPOTENCY HYPOTHESIS

The behavior elicited by electrical stimulation of the rats’ hypothalamus is reviewed. It is concluded: (1) Elicited responses differ significantly from similarbehavior that is evoked by specific motivational states such as hunger and thirst. Hypothalamic stimulation at different regions may activate several different states, but these states are not sufficiently designated to preclude response substitution or justify the application of terms that imply specific drive states; (2) If sufficient opportunity is provided, the great majority of electrodes elicit several different behaviors. In a number of cases, these different behaviors do not share the same motor elements nor do they appear to be related by any common motivational theme. Some of the responses become associated with stimulation only gradually, but eventually may be elicited very reliably; (3) In general, specific predictions of evoked behavior based on anatomical locus would have a low probability of success. Although exceptions were noted, there is a discernible tendency for electrodes at different sites to elicit the same response in a given animal. A number of observations suggest that individual animal and species characteristics are significant determinants of the responses elicited by stimulation; (4) The behavior produced by brain stimulation is in part the concommitant of the responses that tend to be dominant as a result of the interaction of such factors as environmental conditions, the presence of compelling stimuli, and a particular aroused animal. The term «prepotency» was suggested to summarize these factors that are major determinants of the behavior elicited by stimulation. © 1969 S. Karger AG, Basel.