The minimal behavioral time window for reward conditioning in the nucleus accumbens of mice

Abstract

22The temporal precision of reward-reinforcement learning is determined by the minimal time window of 23 the reward action-theoretically known as the eligibility trace. In animal studies, however, such a 24 minimal time window and its origin have not been well understood. Here, we used head-restrained mice 25 to accurately control the timing of sucrose water as an unconditioned stimulus (US); we found that the 26 reinforcement effect of the US occurred only within 1 s after a short tone of a conditioned stimulus (CS). 27The conditioning required the dopamine D1 receptor and CaMKII signaling in the nucleus accumbens 28 (NAc). The time window was not reduced by replacing CS with optogenetic stimulation of the synaptic 29 inputs to the NAc, which is in agreement with previous reports on the effective dopamine timing of NAc 30 synapses. Thus, our data suggest that the minimal reward time window is 1 s, and is formed in the NAc. 31 32 157 indicate 1 mm (left) and 20 m (right). 595

Cell-type specific asynchronous modulation of PKA by dopamine during reward based learning

“…preceding PKA activation provides temporal precision and is required for synaptic plasticity during learning 24,52 .…”