Fos expression in arousal and reward areas of the brain in grass rats following induced wakefulness

►Forced and voluntary wakefulness differentially affect the brain of grass rats. ►Diurnal and nocturnal rodents' brains respond differently to forced wakefulness. ►Most effects of forced wakefulness are reversed by a 2 h rest period. ►The lateral hypothalamus appears to regulate other arousal systems in grass rats.