Figure 2. PFC (Cg1–PLC) activity during a cocaine self-administration session in which the cue is omitted on a random 50% of trials.

Data are presented as in Figure 1. Left: Trials with cue. Note that as in Figure 1, the transient activation of neuronal activity was within 500 ms after cue onset. Right: Trials without cue. Note the complete absence of neuronal activation during the same period after cue onset. Interestingly, a late period of activation emerged on trials without cue at the time of houselight onset (4 s after cue onset).