Fig 1.
Testing apparatus used in the Pilot Study for rats housed in standard (a) and semi-naturalistic (b)cages.
In both cases, the treat cage (48 x 38 x 20 cm) is on the right and is connected to the home cage via a red transparent tunnel (7.6 cm diameter x 7.7 cm long). Tunnel exit into the treat cage was blocked with a piece of Plexiglas during 60 s cue-reward interval. For semi-naturalistic-housed rats, an inverted standard cage was placed inside the home cage. One end of this inverted cage connected to the red tunnel while the other side had a hole (10 cm diameter) covered from the outside with an oversized piece of Plexiglas (‘flap door’) on hinges. A rope system allowed the experimenter to open the flap door when a rat approached, allowing her to enter. This way, rats could not enter unless let in by the experimenter, but once inside, they could exit by pushing on the flap door from the inside. Only one rat was allowed inside at a time.
Table 1.
Ethogram used in the Pilot Study and in Experiments 1–2.
Table 2.
Timeline for Experiment 1.
Table 3.
Timeline for Experiment 2.
Fig 2.
Frequency (a) and percent time (b) of behavioural elements displayed in the Pilot Study.
Data presented as medians with 1st and 3rd quartiles as lower and upper limits of the box, and whiskers as lowest and highest data values;; n = 4 standard cages and n = 5 semi-naturalistic cages; *p<0.05.
Fig 3.
Frequency per minute (a) and percent time (b) for behavioural elements displayed in Experiments 1 and 2.
Bars represent LS means ± SEM. In Experiment 1, n = 4 standard cages and n = 6 semi-naturalistic cages, and in Experiment 2, n = 4 standard cages and n = 5 semi-naturalistic cages. Asterisks denote significant differences between the two housing conditions, where *p<0.05; **p<0.01 and ***p<0.001.
Table 4.
Frequency per minute and percent time for behavioural elements displayed in Experiment 1.
Table 5.
Frequency per minute and percent time for behavioural elements displayed in Experiment 2.