Dopaminergic Prediction Errors Persevere in the Nucleus Accumbens Core during Negative Reinforcement

Hypothetical behavioral results extending those reported in Oleson et al. (2012), with black curves denoting percentage of trials with successful avoidance of footshock and red curves indicating percentage of time freezing during the warning signal. As described by Oleson et al. (2012), rats required ∼15 sessions to reach a behavioral criterion of avoiding shock on at least 50% of trials for three consecutive sessions, indicated by the shaded region. After reaching this criterion, dopamine transmission in the nucleus accumbens core was recorded using fast-scan cyclic voltammetry in a single session, indicated by the arrow. Two possible behavioral outcomes are illustrated. A, The recorded session may have occurred at an intermediate stage of training as rats were still acquiring the avoidance response. With further training (dashed lines), they might eventually reach 100% avoidance and show little freezing behavior during the warning signal. B, Alternatively, the rats may have already reached approximately asymptotic behavior at just over 50% avoidance. Further training would not increase avoidance, and freezing might persist during the warning signal.