Related Papers
Proceedings of the National Academy of Sciences
Two forces for arousal: Pitting hunger versus circadian influences and identifying neurons responsible for changes in behavioral arousal
2007 •
Rae Silver, I. Carren-lesauter
PLoS ONE
Isolating Neural Correlates of the Pacemaker for Food Anticipation
2012 •
Ian Blum
Chronobiology International
THE FOOD-ENTRAINABLE OSCILLATOR: A NETWORK OF INTERCONNECTED BRAIN STRUCTURES ENTRAINED BY HUMORAL SIGNALS?
2009 •
John F Araújo
Physiology & Behavior
Persistent meal-associated rhythms in SCN-lesioned rats
1986 •
Grahame Coleman
Appetite
Oscillators entrained by food and the emergence of anticipatory timing behaviors
2010 •
Rae Silver
Circadian rhythms are adjusted to the external environment by the light-dark cycle via the suprachiasmatic nucleus, and to the internal environment of the body by multiple cues that derive from feeding/fasting. These cues determine the timing of sleep/wake cycles and all the activities associated with these states. We suggest that numerous sources of temporal information, including hormonal cues such as corticoids, insulin, and ghrelin, as well as conditioned learned responses determined by the temporal relationships between photic and feeding/fasting signals, can determine the timing of regularly recurring circadian responses. We further propose that these temporal signals can act additively to modulate the pattern of daily activity. Based on such reasoning, we describe the rationale and methodology for separating the influences of these diverse sources of temporal information. The evidence indicates that there are individual differences in sensitivity to internal and external signals that vary over circadian time, time since the previous meal, time until the next meal, or with duration of food deprivation. All of these cues are integrated in sites and circuits modulating physiology and behavior. Individuals detect changes in internal and external signals, interpret those changes as "hunger," and adjust their physiological responses and activity levels accordingly.
Journal of Neurochemistry
Food-reward signalling in the suprachiasmatic clock
2010 •
jorge mendoza
Neural Mechanisms of Food-Anticipatory Circadian Rhythms in Rats
Glenn Landry
Circadian rhythms of behavior and physiology in rodents are regulated by a system of endogenous circadian oscillators synchronized to the external environment by two distinct pacemakers that are mutually coupled under normal conditions. The suprachiasmatic nucleus (SCN) is the master light-entrainable pacemaker (LEP) that mediates synchrony to the day-night cycle. The second pacemaker is a food-entrainable pacemaker (FEP) and has yet to be identified, but is capable of synchronizing circadian rhythms to restricted feeding (RF) schedules independent of the SCN. Rat, hamster and mouse behavior and physiology entrains to RF despite complete SCN ablations. The studies that comprise this dissertation examine two candidate FEP structures: the thalamic paraventricular nucleus (PVT); and the dorsomedial hypothalamus (DMH). Both the PVT and DMH are promising targets given evidence suggesting they: 1) are active in anticipation of the feeding window (as described in glucose metabolism and c-f...
Physiology & behavior
Evidence for a separate meal-associated oscillator in the rat
1982 •
Grahame Coleman
Three experiments were conducted to explore the relationship between food availability and the wheel running activity rhythms of intact rats. In two experiments re-entrainment when meal times were changed was studied. The rats showed an increase in activity immediately prior to a regular feeding time and this increase was more rapid when rats had been fed at that time in an earlier condition. Some evidence of transients at a former meal time was observed when the meal time was shifted to later in the day, but not when the meal time was shifted to earlier in the day. This led to the hypothesis that ad lib feeding masks rather than abolishes meal-entrained activity. In a third experiment, therefore, rats were entrained to a daily meal under a light-dark (LD) cycle, then placed in constant dark (DD) on ad lib food with occasional periods of deprivation. A burst of activity associated with the former meal time occurred during the deprivation period, but not during ad lib periods; it ret...
European Journal of Neuroscience
A daily palatable meal without food deprivation entrains the suprachiasmatic nucleus of rats
2005 •
carolina escobar
Food is considered a potent Zeitgeber for peripheral oscillators but not for the suprachiasmatic nucleus (SCN), which is entrained principally by the light–dark cycle. However, when food attains relevant properties in quantity and quality, it can be a potent Zeitgeber even for the SCN. Here we evaluated the entrainment influence of a daily palatable meal, without regular food deprivation, on the circadian rhythm of locomotor activity and the c-Fos and PER-1 protein expression in the SCN. Rats fed ad libitum, in constant darkness, received a palatable meal for 6 weeks starting in the middle of the subjective day. Locomotor activity showed entrainment when the offset of activity coincided with the palatable meal-time. In the SCN, the peak expression of c-Fos was observed at palatable meal-time and PER-1 showed a peak during the onset of subjective night, as predicted according to the behavioural entrained pattern. In addition, c-Fos and PER-1 expression in the paraventricular thalamic nucleus (PVT) showed increased expression at palatable meal-time, while the intergeniculate leaflet did not, suggesting that the PVT may be involved as an input pathway of palatable food-entrainment to the SCN. These results demonstrate that daily access to a palatable meal can entrain the SCN; several stimuli can be implicated in this process, including motivation and arousal.
Journal of Biological Rhythms
Correlation with Behavioral Activity and Rest Implies Circadian Regulation by SCN Neuronal Activity Levels
2009 •
Thijs Houben, Johanna Meijer
