Figure 3.

Confirmation of cue-evoked phasic ACh release when cues are detected, but not missed. Fixed-potential amperometry was used to measure choline currents in the right PFC of animals performing a cued appetitive response task (n = 2; field potentials were recorded using the same electrodes). A, Example of single trials showing changes in choline currents on a trial where the cue was detected (red) and a trial when the cue was missed (blue). For each trace, the first data point has been set to 0, and each subsequent point reflects the change in choline concentration from this point. The yellow shaded area represents the 1 s cue presentation window. B, Population average of choline currents observed during detected (29 trials) versus missed cues (11 trials). Choline currents began to rise with the onset of the cue, but only when such cues were detected. Currents reached their peak within seconds, and then began to decline before reward presentation 6 ± 2 s later. These results confirm our prior findings supporting a selective role for phasic ACh release in cue detection (Parikh et al., 2007; Howe et al., 2013). Error bars indicate SEM. *p < 0.05 versus precue choline concentrations.