Analysis of the encoding properties of nucleus accumbens neurons during learning of a self-paced operant conditioning task.

JUAN BELFORTE; MARIA FLORENCIA SANTOS; CAMILA L. ZOLD

Congreso; XXXII CONGRESO ANUAL SAN 2017; 2017

The available behavioral and anatomical evidence points strongly toward a role of nucleus accumbens (NAc) in promoting behavioral responses associated with reward and it has been proposed to function as a limbic-motor interface. Recordings in NAc in animals performing operant conditioning tasks have revealed phasic responses, in partially overlapping subpopulations, correlated with different aspects of the task, including motor responses and reward associated cues. However, little is known about how this responses evolve place during learning of a behavioral task. To unveil the evolution of encoding properties of NAc neurons along the acquisition of an operant conditioning task we implanted Long-Evans male rats with a microelectrode array in the NAc. Rats were motivated by water restriction to obtain water droplets from a lick tube located within a recessed ?nose-poke? in a standard behavioral chamber. Rats were daily trained using a protocol in which trials were self-paced by the animal. Animals were required to lick 8 times for a water reward to be presented. To differentiate reward receipt from expectancy, half of the total correct trials were rewarded, half unrewarded. We identified different subpopulations of units responding to environmental salient events and motor responses. Interestingly, signaling properties and population composition of the NAc responses evolved along the learning of the task, supporting the notion that NAc participates in the learning process.