Fig. 1.

The injection procedure used for light inactivation and dark I and dark II inactivation. A dashed vertical line and Inject denote the time of injection; Inact indicates the trials used for the inactivation condition. A, In light inactivation, the first five trials serve as control trials for comparison with trials 6–10 that are inactivation trials. The final set of five trials was used to ensure that behavioral and electrophysiological changes returned toward control levels. B, In dark I inactivation, the injection occurred before the onset of dark trials.C, In dark II inactivation, the injection took place after the first five dark trials.