Figure 2.

Photoactivation of VMN^NOS1 neurons elicits both glucose CRRs and defensive freezing immobility. Blood glucose levels during unilateral laser off (mock) and laser-induced stimulation (Stim) of VMN^NOS1 neurons in ChR2-YFP–injected (n = 10) (A) or YFP control–injected (n = 3) (B) animals. Blue shading represents the duration of laser stimulation. Blood glucose values from ChR2-YFP animals at the 60-min time point (C) during which tail blood was collected for measurement of insulin (D), glucagon (E), and corticosterone (F). G: Percentage of photoactivation trials evoking freezing. Percentage of time spent immobile (H), total distance traveled (I), and average velocity (J) during mock and photostimulation. Values are mean ± SEM. P values by two-way ANOVA (A and B) or two-tailed, paired Student t test (C–J). **P < 0.01; ***P < 0.001; ‡P < 0.0001.