Fig. 1. Locomotor activity and temporospatial organization of trajectories in young mice. ( A ) Distance moved in the open field before (baseline) and 24 h after anesthesia. Anesthesia reduced the distance moved in mice lacking the β2subunit of the nicotinic acetylcholine receptor (β2KO) ( P < 0.05) but not in wild-type (WT) mice (not significant). ( B ) Activity in the plus maze expressed as number of transitions between the closed arms of the maze. Anesthesia reduced locomotor activity in β2KO mice ( P < 0.05) but not in WT mice (not significant). ( C ) Spatiotemporal organization of trajectories in the open field. The number of large movements from the peripheral area (PA) across the central area (CA) of the open field is indicated by #PA-CA-PA. The conditional probability of a transition from a PA to a CA state, i.e. , the probability of moving from the periphery to the center, is indicated by % PA-CA. ( D ) Spatiotemporal organization of trajectories in young mice. All values are compared relative to the WT control group, which is set to 100%. Exploration index (explo index) provides information on the repartition of fast versus slow movements in the open field and is obtained by dividing time spent at slow movement speed with time spent in fast movement speed. Young control β2KO mice differed significantly from young control WT mice regarding exploration index ( P < 0.01) ( D ,left) , %PA-CA ( P < 0.01) ( D ,middle) , and #PA-CA-PA ( P < 0.01) ( D ,right) . After sevoflurane anesthesia, exploration index ( D ,left) , %PA-CA ( D ,middle) , and #PA-CA-PA ( D ,right ) in young β2KO mice were no longer significantly different from those in young WT mice. No effect of anesthesia on these behavioral parameters was demonstrated in young WT mice. Statistical significance for planned comparisons between control and anesthesia groups is indicated above the corresponding horizontal lines. Symbols within vertical bars indicate statistical significance for planned comparison with WT control. ko =β2knockout control group (n = 18); ko + sevo =β2knockout anesthesia group (n = 8); wt = wild-type control group (n = 20); wt + sevo = wild-type anesthesia group (n = 11). * P < 0.05. ** P < 0.01. *** P < 0.001. - P > 0.05.