Extended Data Fig. 2: Trial initiation latency was modulated by total value.
From: A neural substrate of sex-dependent modulation of motivation
a. Trial-by-trial total value (QCh + QU, where QCh and QU are the action values for the chosen and unchosen lever, respectively) was divided into quartiles for each animal, and trial initiation latencies were averaged in quartile bins. To compare how total value influenced trial initiation latency in males and females we fit the following mixed effects regression: trial_initiation_latency ~ Sex + Total_value + Trial + Weight + Sex:Total_value + Trial:Total_value + Trial:Sex + Weight:Total_value + Weight:Sex + Weight:Sex:Total_value + Trial:Sex:Total_value + (1 + Total_value + Weight + Trial + Weight:Total_value + Trial:Total_value|subject) + (1 + Total_value + Trial + Total_value:Trial|session:subject). Model was fit with effects coding and significance was determined with F tests using the Satterthwaite method to estimate degrees of freedom. Total value and the interaction between sex and total value significantly affected trial initiation latency (Sex: F(1,56.35) = 4.13, p = 0.05; Trial: F(1,66.31) = 355.60, p < 0.001; Total_value: F(3,108.22) = 84.79, p = 2.71 × 10−28; Weight: F(1,57.03) = 12.21, p = 9.27 × 10−4; Trial:Sex: F(1, 66.31) = 2.42 p = 0.13; Trial:Total_value: F(3,97.95) = 49.40, p = 1.56 × 10−19; Sex:Total_value: F(3, 108.22) = 19.03, p = 5.52 × 10−10; Sex:Weight: F(1, 57.03) = 11.97, p = 0.001; Total_Value:Weight: F(1,144.71) = 17.59, p = 8.66 × 10−10; Trial:Sex:Total_value: F(3, 97.95) = 0.10, p = 0.96; Weight:Sex:Total_value: F(3, 144.71) = 1.52, p = 0.21). Specifically, females were slower than males to initiate low total value trials (2-sided Wilcoxon rank sum tests between males and females: bin 1: Z = 4.06, p = 4.99 × 10−5; bin 2: Z = 3.46, p = 5.42 × 10−4; bin 3: Z = 3.17, p = 0.002; bin 4: Z = 1.75 p = 0.08). n = 37 females, 35 males. b. Inhibition of ACC-DMS neurons decreased the influence of total value on trial initiation latency in females. To determine how the effect of inhibition on trial initiation latencies was influenced by sex and opsin, we divided trials into quartile bins of total value and averaged trial initiation latencies for laser and non-laser trials in each bin. We then fit a linear mixed-effects model to the difference between laser and non-laser trials with sex, total value, opsin and their interactions as fixed effects and random intercepts for each subject. The effect of inhibition depended on sex and and its interaction with opsin (2-sided F-tests: sex:opsin: F(1,29) = 4.95, p = 0.03, sex: F(1,29) = 14.48, p = 6.77 × 10−4; opsin: F(1,29) = 3.25, p = 0.08; total value: F(1,29) = 4.13, p = 0.01, sex:total value quantile: F(3,29) = 1.51, p = 0.23; opsin:total value quantile: F(3,29) = 0.36, p = 0.78, sex:opsin:total value quantile: F(3,29) = 0.55, p = 0.65). Specifically, females expressing NpHR were significantly faster to initiate trials following inhibition compared to control trials (2-sided Wilcoxon rank sum tests, bin 1: W = 35, p = 0.02; bin 2: W = 35, p = 0.02; bin 3: W = 36, p = 0.008, bin 4: W = 36, p = 0.008). In males, trial initiation latencies for laser and non-laser trials did not differ in any bin (2-sided Wilcoxon signed rank tests, p > 0.1 for all comparisons). n = 8 females, 9 males. c. Significantly more neurons encoded upcoming total value during the outcome in females than males (χ2-test, χ2(1,N = 756) = 13.58, p = 2.3 × 10−4). Proportions of neurons encoding current trial total value did not differ between males and females for any task event (χ2-tests, all p > 0.3). d. Outcome activity was averaged across time (8 seconds from presentation of the outcome) and averaged in 3 quantile bins of total value. The left plots show the value modulation for all total value encoding neurons in females and males and the right-most plot shows the mean and SEM across neurons for males and females. (a, b) Circles are data from individual mice and lines show across animal averages and error bars standard error of the mean. * p < 0.05, ** p < 0.01, ***p < 0.001.
