scholarly journals Tonic firing mode of midbrain dopamine neurons continuously tracks reward values changing moment-by-moment

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Yawei Wang ◽  
Osamu Toyoshima ◽  
Jun Kunimatsu ◽  
Hiroshi Yamada ◽  
Masayuki Matsumoto
Keyword(s):  
Animal Behavior ◽  
Continuous Monitoring ◽  
Dopamine Neurons ◽  
Neuron Activity ◽  
Behavioral Regulation ◽  
Tonic Firing ◽  
Phasic Activity ◽  
Firing Mode ◽  
Midbrain Dopamine ◽  
Midbrain Dopamine Neurons

Animal behavior is regulated based on the values of future rewards. The phasic activity of midbrain dopamine neurons signals these values. Because reward values often change over time, even on a subsecond-by-subsecond basis, appropriate behavioral regulation requires continuous value monitoring. However, the phasic dopamine activity, which is sporadic and has a short duration, likely fails continuous monitoring. Here, we demonstrate a tonic firing mode of dopamine neurons that effectively tracks changing reward values. We recorded dopamine neuron activity in monkeys during a Pavlovian procedure in which the value of a cued reward gradually increased or decreased. Dopamine neurons tonically increased and decreased their activity as the reward value changed. This tonic activity was evoked more strongly by non-burst spikes than burst spikes producing a conventional phasic activity. Our findings suggest that dopamine neurons change their firing mode to effectively signal reward values in a given situation.

scholarly journals Tonic firing mode of midbrain dopamine neurons continuously tracks reward values changing moment-by-moment

2020 ◽  
Author(s):  
Yawei Wang ◽  
Osamu Toyoshima ◽  
Jun Kunimatsu ◽  
Hiroshi Yamada ◽  
Masayuki Matsumoto
Keyword(s):  
Continuous Monitoring ◽  
Action Selection ◽  
Dopamine Neurons ◽  
Neuron Activity ◽  
Tonic Activity ◽  
Tonic Firing ◽  
Phasic Activity ◽  
Firing Mode ◽  
Midbrain Dopamine ◽  
Midbrain Dopamine Neurons

AbstractAppropriate actions are taken based on the values of future rewards. The phasic activity of midbrain dopamine neurons signals these values. Because reward values often change over time, even on a subsecond-by-subsecond basis, appropriate action selection requires continuous value monitoring. However, the phasic dopamine activity, which is sporadic and has a short duration, likely fails continuous monitoring. Here, we demonstrate a tonic firing mode of dopamine neurons that effectively tracks changing reward values. We recorded dopamine neuron activity in monkeys during a Pavlovian procedure in which the value of a cued reward gradually increased or decreased. Dopamine neurons tonically increased and decreased their activity as the reward value changed. This tonic activity was evoked more strongly by non-burst spikes than burst spikes producing a conventional phasic activity. Our findings suggest that dopamine neurons change their firing mode to effectively signal reward values, which could underlie action selection in changing environments.

scholarly journals A unified framework for dopamine signals across timescales

2019 ◽  
Author(s):  
HyungGoo R. Kim ◽  
Athar N. Malik ◽  
John G. Mikhael ◽  
Pol Bech ◽  
Iku Tsutsui-Kimura ◽  
...  
Keyword(s):  
Dopamine Neurons ◽  
Prediction Errors ◽  
Temporal Difference ◽  
Unified Framework ◽  
Phasic Activity ◽  
Reward Prediction ◽  
Dynamic Stimulus ◽  
Midbrain Dopamine ◽  
Gradual Approach ◽  
Midbrain Dopamine Neurons

ABSTRACTRapid phasic activity of midbrain dopamine neurons are thought to signal reward prediction errors (RPEs), resembling temporal difference errors used in machine learning. Recent studies describing slowly increasing dopamine signals have instead proposed that they represent state values and arise independently from somatic spiking activity. Here, we developed novel experimental paradigms using virtual reality that disambiguate RPEs from values. We examined the dopamine circuit activity at various stages including somatic spiking, axonal calcium signals, and striatal dopamine concentrations. Our results demonstrate that ramping dopamine signals are consistent with RPEs rather than value, and this ramping is observed at all the stages examined. We further show that ramping dopamine signals can be driven by a dynamic stimulus that indicates a gradual approach to a reward. We provide a unified computational understanding of rapid phasic and slowly ramping dopamine signals: dopamine neurons perform a derivative-like computation over values on a moment-by-moment basis.

Deletion of VGLUT2 in midbrain dopamine neurons attenuates dopamine and glutamate responses to methamphetamine in mice

2021 ◽  
Vol 202 ◽  
pp. 173104
Author(s):  
Hui Shen ◽  
Kai Chen ◽  
Rosa Anna M. Marino ◽  
Ross A. McDevitt ◽  
Zheng-Xiong Xi
Keyword(s):  
Dopamine Neurons ◽  
Midbrain Dopamine ◽  
Midbrain Dopamine Neurons
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