Figure 2.

A) The percentage of hippocampal place cells that changed firing state from on to off, or vice versa, when animals were moved from a recording arena in one room into a different arena located in a different room, was significantly greater for the animals raised in a complex environment (CE group; n=87 cells) compared to cells recorded from animals in the social control (SC; n=83 cells) groups. This difference in cell response was not reflected in differences in basic firing behaviour as firing properties of the CE-group cells that changed state between recording environments were no different to those that did not change, for measures such as B) firing rate and C) place field size. D) The analysis was then restricted to only those cells that returned to the same firing state from A to A′ in an ABA′ manipulation (off/on/off = dashed line, on/off/on = solid line; SC n= 68; CE n = 57). E) For this subgroup of cells, CE-group cells were still more likely to change state than SC-group cells. F) This effect was not due to effects occurring in only one or two animals as the same pattern emerged when the analysis was conducted on a per animal basis (CE, n=7 animals; SC, n=8 animals) (error bars ± sem).