Figure 3.

Ventral pallidum neurons of weight-gainer mice are more hyperpolarized and slower to fire compared with non-weight gainer mice. A, Increase in body weight gain (expressed as a percentage of the first day) during 10–12 weeks of chronic HFHS diet for individual mice. Mice were split into non-weight gainer (bottom 33% of weight gainers on the last day of HFHS diet) and weight-gainer (top 33% of weight gainers on last day of HFHS diet) groups according to final weight gain. B, VP neurons of WG mice were more hyperpolarized than those of NWG mice (unpaired two-tailed t test). C, There was no significant difference in the baseline firing frequency of VP neurons between WG and NWG mice (unpaired two-tailed t test). D, VP membrane potential was negatively correlated with weight gain (Middle, middle 33% weight gainers). Correlation was assessed using nonparametric Spearman correlation. E, F, The firing rates during incrementing depolarization steps did not differ between WG and NWG mice (two-way ANOVA), but the minimal latency to the first action potential was longer in HFHS mice (two-way ANOVA), possibly reflecting decreased excitability. G, Representative traces. Data are taken from 9–16 cells in 7 mice/group. Data are presented as the mean ± SEM. AP, Action potential.