Exploration and Its Measurement: A Psychopharmacological Perspective

The goal of psychopharmacology is twofold: to study the behavioral effects of drugs in order to elucidate mechanisms of drug action and to use drugs as tools in order to ascertain underlying neurochemical processes mediating behavior. In investigating a particular neural system or a certain class of drugs, the most information can be gained by studying a wide range of behaviors. For example, this endeavor may encompass the analysis of motivated behavior (feeding, drinking, sexual behavior), analysis of spontaneously emitted behaviors (activity patterns, exploration), or the study of operant performance, attentional processes, learning, and memory. The present chapter focuses on the effects of drugs on one of these domains of behavior, exploration, with emphasis on the methodological issues involved in the measurement and interpretation of exploratory behavior. These issues have arisen out of theoretical considerations of exploration, and so in the first section we consider the development of the more conceptual aspects of this field. Subsequently, the problems arising in the definition and interpretation of exploratory behavior are addressed, and the methods available for its measurement are reviewed. The final sections provide examples of pharmacological manipulation of exploration, as well as speculations on the neural substrates that may mediate this behavior.