AschofFs rule in diurnal and nocturnal mammals

biological organization, ranging from molecules to humans, including clinical investigations. It is published 12 times a year investigations that illuminate normal or abnormal regulation and integration of physiological mechanisms at all levels of publishes original A neural theory of circadian rhythms: AschofFs rule in diurnal and nocturnal mammals CARPENTER, GAIL A., AND STEPHEN GROSSBERG. A neural curves to pulses of light in diurnal and nocturnal mam-theory of circa&an rhythms: Aschoff's rule in diurnal and nocturnal mammak Am. J. Physiol. 247 (Regulatory Integrative mals, including the " dead zone " of phase resetting insen-Comp. Physiol. 16): R1067-R1082, 1984.-A neural model of sitivity during the subjective day of a nocturnal mammal the suprachiasmatic nuclei suggests how behavioral activity, rest, and'circadian period depend on light intensity in diurnal and of the pacemaker by high light intensities (3, 11). Due to nocturnal mammals. These properties are traced to the action the fact that every process in the model has a physical of light input (external zeitgeber) and an activity-mediated interpretation, the model also suggests a number of an-fatigue signal (internal zeitgeber) on the circadian pacemaker. atomical, physiological, and pharmacological predictions Light enhances activity of the diurnal model and suppresses to test its validity. Notable among these are predictions activity of the nocturnal model. Fatigue suppresses activity in that test whether slowly varying transmitter gating ac-both diurnal and nocturnal models. The asymmetrical action tions form part of the SCN pacemaker. In model circuits of light and fatigue in diurnal vs. nocturnal models explains the more consistent adherence of nocturnal mammals to As-controlling motivated behaviors such as eating and chaffs rule, the consistent adherence of both diurnal and drinking, such slow gating processes have already been nocturnal mammals to the circadian rule, and the tendency of used to analyze a variety of abnormal behaviors, such as nocturnal mammals to lose circadian rhythmicity at lower light juvenile hyperactivity, Parkinsonism, hyperphagia, and levels than diurnal mammals. The fatigue signal is related to simple schizophrenia (13, 14). If a slow gating action is the sleep process S of Borbely (Hum. Neurobiol. 1: 195-204, verified in the SCN, it would provide a new basis for 1982.) and contributes to the stability of circadian period. Two analyzing certain abnormalities of circadian rhythms and predictions follow: diurnal mammals obey Aschoffs rule less their effects on the motivational circuits that they mod-consistently during a self-selected light-dark cycle than in ulate. constant light, and …