Figure 4. Temperature-dependent tolerance is affected by sex and reward salience. A, Female (n = 8) and male (n = 8) mice differed in their tolerance to temperatures in the OPTA with 4% sucrose reward. Below, Representative heat maps of female and male mice in 30/45°C test. B, Male mice increased tolerance to aversive temperatures when 10% sucrose was available (n = 7) compared with a reward of 4% sucrose (n = 8). Below, Representative heat maps of 4% and 10% sucrose conditions. C, Female mice (n = 8) exhibited reduced time in the reward zone when the reward was 10% sucrose compared with a reward of 4% sucrose across temperatures. Below, Representative heat maps of 4% and 10% sucrose conditions. D, Male mice (n = 10 per group) spend more time in reward zone when 4% sucrose is present compared with when an empty bottle is present, unpaired t test (two-tailed). Furthermore, time spent in reward zone is significantly positively correlated with sucrose solution consumption. E, Pearson correlation, y = 185.4 + 114.8. F, Upon removal of the reward, male mice spend less time in the reward zone, paired t test (two-tailed). Note, male and female mice in 4% sucrose condition served as sex and age matched control for 10% sucrose condition. R = reward zone. A–C, Two-way ANOVA with Sidak’s correction. Data are presented as the mean ± SEM; *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001.