Reward-related signaling in the dorsal striatum

BELLUSCIO, MARIANO; MURER, MARIO GUSTAVO; MARTÍNEZ, MARÍA CECILIA

Mar del Plata

Congreso; XXXII Congress of the Argentine Society for Research in Neuroscience; 2017

Argentine Society for Research in Neuroscience

The ability to predict rewarding outcomes is essential for learning and consolidating stimulus- reward associations. The striatum is part of the basal ganglia and it is involved not only in the motor control of a sequence of actions but also in coding other aspects related to a task such as cues that are associated to a reward, estimation of time, reward- prediction error, etc.Here we used tetrodes to record striatal activity in a self-initiated rewarded task. Briefly, after a minimum inter-trial interval of 2.5 s, water-deprived rats must enter a nosepoke and, following a visual cue, emit an eight-licks sequence onto a tube to receive water. Behavioral analysis shows that subjects quickly learn to perform lick sequences but have more difficulties in the control of their timely emission, as they prematurely enter the nosepoke. Premature entries reset the timer, reducing the reward rate, but with training animals learn the action-outcome association, improving their performance in the task. In electrophysiological records we found bracketing-like activity in beginning and the ending of the trials and also activity related to the visual cue and the delivery of the reward. Interestingly, we found neuronal activity modulation that correlates with the length of the ITI, both for correct trials and premature entries with sequences. These findings show that the striatum is coding multiple aspects of the task.