Figure 3.

Activity of VTA neurons and their afferents during a pavlovian-conditioning task. Simulated mean activity (Hz) of each neuron population during a pavlovian-conditioning task, where a tone is presented systematically 1.5 s before a water reward (4 μL). Three different trials are represented: the initial conditioning trial (n = 1, light colors), an intermediate trial (n = 6, medium colors) and the final trial (n = 50, dark colors) and when reward is omitted after learning (dotted lines). Vertical dashed gray and cyan lines represent CS and US onsets, respectively. (A) PFC neurons learn the timing of the task by maintaining their activity until US. (C) PPTg neurons activity responds to the US signal at all trials. (B) VTA GABA persistent activity increases with learning, (D) VTA DA activity increase at the CS and decrease at the US.