Brain-stimulation reward: current issues and future prospects.

Abstract

This commemorative issue began with abrief discussion of the major themes thathave characterized the study of brain-stimulation reward (BSR) over the pasttwenty-five years. This overview, along withthe research papers which follow, clearlyshow that the field continues to be of majorimportance in brain-behaviour research.However, both the astute observer and thedevil's advocate will also see that much ofthis research has led merely to the refine-ment of important questions which relate tothis phenomenon, rather than their resolu-tion. A silver anniversary is an appropriatetime to assess previous developments and toconsider future prospects. If it appears thatanswers will be forthcoming, then every ef-fort must be made to sustain the momen-tum that has characterized the research inthis field in recent years. If, on the otherhand, there are likely to be only further andfurther refinements of issues in the besttraditions of Hesse's Glass Bead Game, thenperhaps this line of research should be sus-pended until we can find a new MagisterLudi to succeed James Olds.In preparing a prospectus on BSR, thereare two basic issues, each with attendantsubordinate issues, which must be con-sidered. They revolve around questionsof structure and function: (1) what arethe neuroanatomical systems subservingbrain-stimulation reward? (2) what func-tions do such systems have in controllingand modifying an animal's behavioural re-pertoire? As indicated in the prologue, re-consideration of the 'structure' question inlight of histochemical neuroanatomy wasresponsible for a resurgence of interest inself-stimulation in recent years. Researchconcerned with 'structure' is still very muchalive and in fact, as suggested below, holdsevery promise of being resolved in the nearfuture. The 'functional' issue has proven tobe more elusive but there are some en-couraging signs that it too may be solved.