Optogenetics. Inhibition of FS-PV activity during attention: SwiChR was activated pseudorandomly in 50% of the trials by 0.5, 1.0 or 2.0 s (separate sessions) of 473 nm blue light upon trial start. SwiChR was deactivated by application of 1 s red light (638 nm) after ending of the pseudorandom delay. Activation of FS-PV neurons during attention: ChR2 was activated by blue light (473 nm at different frequencies) throughout the pseudorandom delay or during the last 2 s of the delay.

(B) Training in the 3-CSRTT. The animals were trained at six levels defined by specific criteria. The criteria of each level had to be met for two consecutive days for progression to the next level. After successfully reaching the target criteria ( = level 6, two consecutive days with ≥ 50 correct trials, ≥ 80% accuracy and ≤ 20% omissions; pseudorandom delay (3, 4 or 5 s), 1 s cue, 5 s maximum response time) the animals were subjected to chronic electrophysiological recordings or optogenetic manipulations.

(C–F) Training data for the animals used; n = 13 PV-Cre mice (3 chronic recordings during behavior + 5 SwiChR during behavior + 5 ChR2 during behavior). Data represent average performance during each training level.

(C) The average number of days (i.e., sessions) spent at each training level.

(D) Development of accuracy (number of correct trials / (number of correct trials + number of incorrect trials)) during training.

(E) Number of premature and omitted responses during the different training levels.

(F) The reaction time for correct and incorrect responses during training. Correct responses are consistently faster than incorrect responses (paired t test).

∗p < 0.05, ∗∗p < 0.01; error bars, mean ± SEM.