ORIGINAL ARTICLESTransient inactivation of the rat nucleus accumbens does not impair guidance of instrumental behaviour by stimuli predicting reward magnitudeGiertler, C.; Bohn, I.; Hauber, W.Author Information Abteilung Tierphysiologie, Biologisches Institut, Universität Stuttgart, Stuttgart, Germany Sponsorship: This research was supported by the Deutsche Forschungsgemeinschaft (Ha2340/3-2). Correspondence and requests for reprints to Dr Wolfgang Hauber, Universität Stuttgart, Biologisches Institut, Abteilung Tierphysiologie, Pfaffenwaldring 57, D-70550 Stuttgart, Germany e-mail: [email protected] Received 4 April 2003 Accepted as revised 5 November 2003 Behavioural Pharmacology: February 2004 - Volume 15 - Issue 1 - p 55-63 Buy Abstract The involvement of the nucleus accumbens (NAc) in the determination of reaction times (RTs) of instrumental responses by the expectancy of future reward was investigated. A simple RT task demanding conditioned lever release was used, in which the upcoming reward magnitude (5 versus 1 pellet) was signalled in advance by discriminative cues. In rats which acquired the task, RTs of instrumental responses were significantly shorter to the discriminative cue predictive of high reward magnitude. Inactivation of the NAc by lidocaine had no effect on RTs and their determination by cue-associated reward magnitudes, and did not affect the rate of correct responses. In keeping with an earlier study, intra-NAc infusion of amphetamine decreased RTs, impaired RT determination by cue-associated reward magnitudes and reduced the rate of correct responses. The unexpected finding that lidocaine inactivation of the NAc had no effect parallels previous data showing that lesions of NAc did not impair RT performance, while manipulation of intra-NAc glutamate or dopamine transmission impaired various aspects of RT performance in comparable tasks. It is suggested that experimental manipulations such as transient and permanent inactivation, which almost completely inhibit NAc neuronal output, allow alternative routes to be used to effectively control behaviour in the task employed here. © 2004 Lippincott Williams & Wilkins, Inc.