Changes to open field surfaces typically used to elicit hippocampal remapping elicit graded exploratory responses

Studies show that changes in environmental context alter the spatial firing patterns (‘remapping’) and increase immediate early gene activation in hippocampal but not subicular neurons. However, such studies rarely report co-occurring behavioural responses. We examined the behavioural effects of habituating rats to a walled open field, and then of changing the environmental context by altering wall patterns and floor colour. These kinds of cue change are known to elicit spatial remapping in hippocampal regions, but not the subiculum. Relative to controls (no cue alterations), alteration of wall patterns elicited significant increases in exploratory locomotion through the open field, while combined alterations of floor colour and wall patterns elicited an even higher increase in exploratory locomotion. In addition, combined alterations (floor colour and wall patterns) significantly increased rearing frequency, and significantly decreased the time the rats spent immobile. These findings are relevant to how changes in environmental context affect neuronal responses in the hippocampal formation, and may aid in the development of novelty-response tasks where novelty resides in open field surfaces.