Graphs illustrating numbers of c-Fos (PC38)-ir/tryptophan hydroxylase- (Tph-) immunostained cells from different rostrocaudal levels of the rat dorsal raphe nucleus (DR) in Experiment 2. Foreground bars represent the numbers of c-Fos (PC38)-ir/Tph-ir neurons. Background bars represent the total numbers of Tph-ir neurons (both c-Fos (PC38)-immunoreactive/Tph-immunoreactive neurons and c-Fos (PC38)-immunonegative/Tph-immunoreactive neurons) within each subdivision. Graphs are arranged (A-H) according to rostrocaudal level in mm from bregma. Abbreviations: CLi, caudal linear nucleus; DRC, dorsal raphe nucleus, caudal part; DRD, dorsal raphe nucleus, dorsal part; DRI, dorsal raphe nucleus, interfascicular part; DRV, dorsal raphe nucleus, ventral part; DRVL/VLPAG, dorsal raphe nucleus, ventrolateral part/ventrolateral periaqueductal gray. *p < 0.05, Sedentary versus Forced LAF exercise. #p < 0.05, Voluntary LAF exercise versus Forced LAF exercise.