Overall, we used 104 male Lister Hooded rats (Charles River), weighing 310–400 g (9–12 weeks old) at the start of experiments. In experiment 1, 72 rats were tested in three batches of 24 rats. Experiment 2 used 32 rats in a single batch. See section below, Experimental design, for further detail and for sample size justifications.
Rats were housed in groups of four in individually ventilated “double decker” cages (462 × 403 × 404 mm; Techniplast) with temperature and humidity control (21 ± 1.5°C, 50 ± 8%) and an alternating 12/12 h light/dark cycle (lights on at 7 A.M.). Rats had ad libitum access to food (Teklad Global 18% protein diet, Harlan) throughout the study. Access to water was restricted during the CER procedure (see details below) but was available ad libitum during all other stages of the study. All rats were habituated to handling by experimenters for at least 5 d before any experimental procedure. All experimental procedures were conducted during the light phase and in accordance with the requirements of the United Kingdom Animals (Scientific Procedures) Act 1986, approved by the University of Nottingham’s Animal Welfare and Ethical Review Board (AWERB) and run under the authority of Home Office project license 30/3357.
Rats were housed in groups of four in individually ventilated “double decker” cages (462 × 403 × 404 mm; Techniplast) with temperature and humidity control (21 ± 1.5°C, 50 ± 8%) and an alternating 12/12 h light/dark cycle (lights on at 7 A.M.). Rats had ad libitum access to food (Teklad Global 18% protein diet, Harlan) throughout the study. Access to water was restricted during the CER procedure (see details below) but was available ad libitum during all other stages of the study. All rats were habituated to handling by experimenters for at least 5 d before any experimental procedure. All experimental procedures were conducted during the light phase and in accordance with the requirements of the United Kingdom Animals (Scientific Procedures) Act 1986, approved by the University of Nottingham’s Animal Welfare and Ethical Review Board (AWERB) and run under the authority of Home Office project license 30/3357.