Fig 1. Late-life social isolation increases exploration and hyperactivity in female mice.

(a) Experimental timeline and behavioural test-order. OF = open field, SI = 3-chambered social interaction task, EPM = elevated plus maze, FST = forced swim task, CFC = context fear conditioning. In the open field task, (b) isolated mice (black, closed circles) travel further distance, (c) move at a faster speed, (d) make more entries into the center of the open field arena, and (e) spend less time in the periphery of the arena than group-housed controls (white, open circles), indicating a less anxiety-like phenotype. In the elevated plus maze, (f) isolated mice travel further distance and (g) move at a faster speed, but (h) make a comparable number of entries into the open arms of the maze, and (i) spend an equivalent amount of time in the closed arms of the elevated plus maze as controls. In the social interaction task, (j) isolated and group-housed control mice spend an equivalent amount of time in the chamber containing the conspecific, (k) make a similar number of entries into the zone surrounding the conspecific’s cage, (l) interact for a comparable length of time with the conspecific, and (m) make a similar number of nose pokes into the conspecific’s cage. Error bars represent the standard error of the mean (SEM). * p < 0.05, ** p < 0.01, ns p > 0.05.