TY - JOUR TI - Tonic firing mode of midbrain dopamine neurons continuously tracks reward values changing moment-by-moment AU - Wang, Yawei AU - Toyoshima, Osamu AU - Kunimatsu, Jun AU - Yamada, Hiroshi AU - Matsumoto, Masayuki A2 - Lee, Daeyeol A2 - Wassum, Kate M A2 - Lee, Daeyeol A2 - Roesch, Matthew VL - 10 PY - 2021 DA - 2021/03/10 SP - e63166 C1 - eLife 2021;10:e63166 DO - 10.7554/eLife.63166 UR - https://doi.org/10.7554/eLife.63166 AB - 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. KW - dopamine neuron KW - reward KW - value KW - Macaca fuscata JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -