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. 2022 May 17;47(8):1561–1573. doi: 10.1038/s41386-022-01336-y

Fig. 2. Methamphetamine intake across the 22-day IVSA period.

Fig. 2

a males and b females had access to a low METH dose (0.03 mg/kg/infusion) for the first 10 days, which was increased to the high dose (0.1 mg/kg/infusion) for the remaining 12 days. The inset graphs show total METH intake across MS and treatment conditions for each METH dose and total METH intake is depicted in c for males and d for females. Lever pressing during the daily extinction sessions for e male and f female rats. Inset graphs depict the number of extinction sessions required until rats reached the extinction criterion. Data are shown as mean ± SEM. *p < 0.05 significant interaction effect. OXY = Oxytocin, VEH = Vehicle. Sample size (N = 112) was reduced by the removal of 22 rats due to loss of catheter patency (n = 4 males), for not discriminating between the active and inactive lever (did not have a ratio of active to inactive lever presses of 2:1 per session for the last three acquisition sessions), or for not acquiring METH IVSA (did not take greater than 10 infusions per session over the last three acquisition sessions; male: n = 9, MS15 OXY = 4, MS360 VEH = 3, MS360 OXY = 2; female: n = 9, MS15 OXY = 5, MS360 VEH = 1, MS360 OXY = 3). This resulted in a sample size of 90 rats (males = 45, females = 45) with 10–13/condition/sex.