Self-stimulation behavior: Methods evaluating intracranial reward and their relations with motivational states

Abstract

Monopolar electrodes were chronically implanted in the posterior lateral hypothalamus of male rats. Animals exhibiting steady self-stimulation behavior were allowed to self-administer brain stimulation using various procedures: a continuous reinforcement schedule, fixed ratio procedures, choice method, cost methods, consummatory procedures, determination of the extinction of self-stimulation behavior, self-regulation of train duration stimulation, and the switch-off method. Results of factor analysis support the difficulty of objectively favoring one method over another. Three “motivational procedures,” that is, feeding, sexual, and aggressive behaviors, were also designed to study the relationships between drive state and rewarding strength elicited by hypothalamic stimulations. Interpretations of these relationships in terms of drive reduction or drive induction hypotheses show how complex the nature of the relation is, indicating that these interpretations depend on the ability to interpret the multifactorial nature of the reinforcing effect.