Dopamine Encodes Retrospective Temporal Information in a Context-Independent Manner

Abstract

Summary The dopamine system responds to reward-predictive cues to reflect a prospective estimation of reward value, though its role in encoding retrospective reward-related information is unclear. We report 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.

Pattern of dopamine signaling during aversive events predicts active avoidance learning

“…We identified both increases and decreases in VMS dopamine levels that occurred during distinct periods of the aversive event, which suggests the discrepancies between earlier microdialysis studies likely arise from differences in the experimental parameters of the aversive task. We previously found that the engagement of the dopamine system during reward-based Pavlovian conditioning can be influenced by changes in the training context (35). Therefore, the training procedures, aversive cue duration, intensity and frequency of the footshock, presence of safety cues, and location of the recordings in the ventral striatum are all factors that likely contribute to the dopamine signals observed during aversive tasks (11,25,(31)(32)(33)(34)(36)(37)(38).…”

“…Voltammetry Recordings. Chronically implanted carbon-fiber microelectrodes were connected to a head-mounted voltammetric amplifier for dopamine detection in behaving rats using fast-scan cyclic voltammetry as described previously (35,45). The potential applied to the carbon fiber was ramped in a triangular waveform from −0.4 V (vs. Ag/AgCl) to +1.3 V and back at a rate of 400 V/s during a voltammetric scan and held at −0.4 V between scans at a frequency of 10 Hz.…”

Prefrontal D1 dopamine-receptor neurons and delta resonance in interval timing

“…During interval timing, the need for cognitive control is triggered by the cue, which initiates temporal processing (Buhusi and Meck 2005;Meck et al 2008). In fixed-interval timing tasks, the cue functions as a reward-predictive CS+ involving phasic dopamine release from midbrain dopamine neurons (Schultz 1997;Fonzi et al 2017). D1DR neurons respond to this phasic dopaminergic release early in the interval and initiate temporal processing via delta-range coherence with MFC ramping neurons.…”

Ventral Tegmental Dopamine Neurons Participate in Reward Identity Predictions

“…Consistent with this view, direct activation of DA neurons serves as a potent reinforcer of instrumental behavior in self-stimulation procedures [7, 18–22]. More recently, contributions of phasic DA signals to model-based learning have been suggested, based on evidence that DA neurons have access to higher-order knowledge for RPE computation [23–27]. Moreover, DA neurons were shown to respond to valueless changes in sensory features of expected rewards [28], and DA neuron optogenetic inhibition prevented learning induced by changing either reward identity or value [29].…”