Dopamine Encodes Retrospective Temporal Information in a Context-Independent Manner

Publication date: 22 August 2017
Source:Cell Reports, Volume 20, Issue 8
Author(s): Kaitlyn M. Fonzi, Merridee J. Lefner, Paul E.M. Phillips, Matthew J. Wanat
The dopamine system responds to reward-predictive cues to reflect a prospective estimation of reward value, although its role in encoding retrospective reward-related information is unclear. We report that cue-evoked dopamine release in the nucleus accumbens core encodes the time elapsed since the previous reward or rather the wait time. Specifically, a cue that always follows the preceding reward with a short wait time elicits a greater dopamine response relative to a distinct cue that always follows the preceding reward with a long wait time. Differences in the dopamine response between short wait and long wait cues were evident even when these cues were never experienced together within the same context. Conditioned responding updated accordingly with a change in cue-evoked dopamine release but was unrelated to a difference in the dopamine response between cues. Collectively, these findings illustrate that the cue-evoked dopamine response conveys a subjective estimation of the relative reward rate.

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Teaser

Fonzi et al. demonstrate that cue-evoked dopamine release encodes retrospective time-related information. They find that the dopamine system can discern differences between cues that have never been experienced together in the same context.


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