Different regions of the striatum regulate different types of behavior. However, how dopamine signals differ across striatal regions and how dopamine regulates different behaviors remain unclear. Here, we compared dopamine axon activity in the ventral, dorsomedial, and dorsolateral striatum, while mice performed a perceptual and value-based decision task. Surprisingly, dopamine axon activity was similar across all three areas. At a glance, the activity multiplexed different variables such as stimulus-associated values, confidence and reward feedback at different phases of the task. Our modeling demonstrates, however, that these modulations can be inclusively explained by moment-by-moment changes in the expected reward, i.e. the temporal difference error. A major difference between areas was the overall activity level of reward responses: reward responses in dorsolateral striatum were positively shifted, lacking inhibitory responses to negative prediction errors. The differences in dopamine signals put specific constraints on the properties of behaviors controlled by dopamine in these regions.
- Iku Tsutsui-Kimura
- Hideyuki Matsumoto
- Naoshige Uchida
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All procedures were performed in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by the Harvard Animal Care and Use Committee (protocol #26-03). All surgeries were performed under aseptic conditions with animals anesthetized with isoflurane (1-2% at 0.5-1.0 l/min). Analgesia was administered pre (buprenorphine, 0.1 mg/kg, I.P) and postoperatively (ketoprofen, 5 mg/kg, I.P).
- Joseph F Cheer, University of Maryland School of Medicine, United States
© 2020, Tsutsui-Kimura et al.
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