Figure 1. The IntelliCage system.
A. Schematic representation of the IntelliCage five-phase protocol. 1) Free adaptation: all four corners and door were opened, giving access to 2 water bottles (blue circles) per corner (D1 to L4). 2) Nose-poke adaptation: all doors were closed and could be opened once per visit in response to a minimum of successive 5s nose-poke (D5 to L7). 3) Place learning: one bottle of each corner was replaced with an 8% sucrose solution (green circle). Each pair of mice had a designated corner (correct corner) in which they could access water or sucrose in response to a 5s nose-poke. The other corners were accessible but not the bottles (red circles) (D8 to L10). 4) Reversal Learning: the correct corner was set as the opposite corner (D11 to L13). 5) Fixed schedule drinking (FSD): water access was restricted to two one-hour time periods during the light phase (11 am and 4 pm) (D14 to L22). Timeline: grey and white rectangles correspond to dark (D) and light (L) periods, respectively and yellow rectangles represent the change of protocol period; blue arrows show hours of accessible water in the FSD. B. Conditioned chamber: accessible via a ring containing a transponder reader antenna and presence is confirmed by temperature-differential sensor. C. 5s Nose-poke water access.