Society for Neuroscience Abstracts 27 (abstract #422.5).

Impulsive choice induced in rats by lesions of the nucleus accumbens core, but not of anterior cingulate or medial prefrontal cortex
Rudolf N. Cardinal, David R. Pennicott, C. Lakmali Sugathapala, Trevor W. Robbins and Barry J. Everitt
Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK.

Impulsive choice is exemplified by the choice of reward that is small, poor, or ultimately disastrous, but is available immediately, in preference to a larger reward obtainable only after a delay. Impulsive choice contributes to neuropsychiatric disorders such as drug addiction as well as attention-deficit/hyperactivity disorder (ADHD), mania, and personality disorders. Impulsive choice hypothetically results from dysfunction of limbic corticostriatal circuitry implicated in reinforcement processes, via convergence on the nucleus accumbens. In this first study of the neuroanatomical basis of impulsive choice, we show that lesions of the nucleus accumbens core (AcbC) induce impulsivity by dramatically and persistently impairing rats' ability to choose a delayed reinforcer. In contrast, lesions of the anterior cingulate cortex (ACC) or medial prefrontal cortex (mPFC) had no effect on this capacity, although mPFC lesions appeared to affect general behavioural timing mechanisms. Thus, dysfunction of the AcbC may be a key element in the neuropathology of impulsivity.

Supported by: MRC (UK)