Topic: fear associations

The neuromodulator dopamine has qualities of a prediction error in temporal difference (TD) models of reward learning. However, the neuromodulatory substrates of threat prediction errors have remained elusive. Norepinephrine (NE) is released by surprise and uncertainty, and causal manipulations demonstrate a role for NE in threat learning. Thus, we hypothesized that NE encodes a threat prediction error signal, and compared NE release measurements in mice undergoing threat learning with predictions of TD learning. NE release scales with the strength of fear associations and threat imminence. Ho