Figure 4.

A steady-state pattern of dopamine release is unmasked by optical suppression. Recordings from a rat in which no transients or dopamine release were observed until laser was administered. Top color plot (conventions as in Figure 3A) shows a single trial in which laser was switched on (green bar) and bottom color plot shows single trial in which laser was not switched on. Bottom panels show dopamine concentration traces extracted from color plots. In this rat, steady state dopamine release was not evident until laser was used to activate NpHR.