FOSB and atrial fibrillation: Both 12 h acute fasting (AF 12 h) and 12 h intermittent fasting (IF 12 h) increased the number of cells co-expressing orexin A and FosB/ΔFosB in the lateral hypothalamus compared with that of control (Fig. 4a,b; ***p < 0.0001 vs. control group).