Figure 9:

Simulation 1d: Differential effect of increasing delays on LV, PV learning. (a) Empirical results adapted from Fiorillo, Newsome & Schultz (2008), Figure 2a,c, with permission from Springer Nature: Nature Neuroscience, copyright 2008, showing a relatively modest decrease in CS-generated dopamine cell bursting with increasing CS-US intervals and and an even greater preservation of US-triggered bursting. Results are from the subject (monkey B) that showed the greater sensitivity to temporal delay. (b) Simulation results show a qualitatively similar pattern due to one potential mechanism — a deterioration in the fidelity of temporally-evolving US representations in OFC (USTime_In) projecting to VS patch layers. (c) Empirical results from Flagel et al. (2011, Figure 2b,e) adapted with permission from Springer Nature: Nature, copyright 2010, showing greater CS-triggered extracellular dopamine signaling in the NAc and near-complete loss of US-triggered dopamine in sign-trackers (top; blue) versus goal-trackers (bottom; gold). (d) Simulations results showing a qualitatively similar pattern based on two possible mechanisms: 1) higher representational fidelity in sign-trackers (top) versus goal-trackers (bottom) for temporally-evolving goal-state representations (PV learning); and, 2) a greater contribution of VS matrix-mediated disinhibition to CS-triggered dopamine signaling (LV learning). (e) Results adapted from Fiorillo, Newsome & Schultz (2008), Figure 2b,d, with permission from Springer Nature: Nature Neuroscience, copyright 2008, showing different sensitivity to temporal delay in the two monkeys they recorded from: left panel: CS-triggered responses; right panel: US-triggered responses; note that monkey B (gray curves in both panels) appears to show considerably more delay sensitivity than monkey A (black) for both CS- and US-triggered dopamine signaling.