The novel two-chamber intra-/extradimensional Operon task reliably measures attentional set shifting abilities in mice. (A) Trials and (B) time (in minutes) needed to reach the criterion in the different stages of the intra/extradimensional Operon task. (C) Time (in seconds) elapsed between the opening of the divider door and a nose-poke response (latency to respond) during the different stages of the task. Twenty-six mice were tested; four mice were excluded because they were not reliably poking to retrieve the food reinforcement during the training or were not able to finish the entire procedure. All other mice readily learned to poke in the holes for food rewards and were able to perform the multiple sequences of discriminations. SD, simple discrimination; CD, compound discrimination; CDRe, compound discrimination reversal; IDS, intra-dimensional shift; IDSRe, intra-dimensional shift reversal; IDS2, intra-dimensional shift 2; IDS2Re, intra-dimensional shift 2 reversal; EDS, extra-dimensional shift; EDSRe, extra-dimensional shift reversal. Note that the mice were able to complete the entire task in 5–9 days. *p < 0.05. Values represent mean ± SEM. Modified from Scheggia et al., Biological Psychiatry 2014.