Fig. 4

vHP MCH signaling increases impulsive choice but not food motivation or timing accuracy. a MCH (1 µg in the vHP) effects on performance in the delay discounting task (two-way repeated measures ANOVA with delay × drug treatment; n = 9). Results show a significant delay × drug interaction (F_(3,24) = 5.53; P = 0.005)_, with main effect of delay time (F_(3,24) = 18.21; P < 0.0001). (b–d; Two-way repeated measures ANOVA (time × drug)). b Effect of vHP MCH injection (n = 15) and c chemogenetic activation of vHP projecting MCH neurons (n = 8) on standard chow intake in the home cage. (d Effect of vHP MCH injection on high fat/high sugar (HFD) diet intake (n = 15). e MCH (1 µg in the vHP) effect on the number of pellets earned in the progressive ratio task (Student’s two-tailed, paired t test; n = 6). f Effect of 1 µg of MCH (0.5 µg/side) in the vHP on distance traveled in the open field test (Student’s two-tailed, paired t test; n = 10). g–i Effect of chemogenetic activation of MCH neurons on peak interval timing (n = 6). g Peak interval response rates during probe trials, with increased response rates that peaks near the 20 s criterion duration; h normalized function for peak rate, where the peak function for each animal was converted to a percentage of maximum response rate. This analysis revealed no horizontal shift in the peak interval timing function (two-way repeated measures ANOVA; F_(1,5) = 1.63, 0.25) following activation of MCH neurons by lateral ventricle CNO injections. i MCH neuronal activation also had no influence on food cup approach behavior during the peak interval test (Student’s two-tailed, paired t test). Data shown as mean ± SEM; (*P < 0.05). Source data are provided as a source data file