The circadian rhythm of locomotor activity in mice is synchronized to environmental factors such as light and food availability. It is well-known that entrainment of the activity rhythm to the light-dark cycle is attained by the circadian pacemaker in the suprachiasmatic nucleus (SCN). Locomotor activity is also controlled by two extra-SCN oscillators; periodic food availability entrains the fo...

Nocturnal rodents show diurnal food anticipatory activity when food access is restricted to a few hours in daytime. Timed food access also results in reduced food intake, but the role of food intake in circadian organization per se has not been described. By simulating natural food shortage in mice that work for food we show that reduced food intake alone shifts the activity phase from the nigh...

Although tropical forests cover only 6% of Earth's arable surface, they account for nearly 50% of all known species (National Research Council, 1992). Despite this diversity, these systems are increasingly threatened, as exemplified by a recent Food and Agriculture Organization report (FAa, 1999) which indicates that tropical countries are losing 127,300 km2 of forest annually; this does not co...

The anticipation of the pleasure derived from food intake drives the motivation to eat, and hence facilitate overconsumption of food, which ultimately results in obesity. Brain imaging studies provide evidence that mesolimbic brain regions underlie both general as well as food-related anticipatory reward processing. In light of this knowledge, the present study examined the neural responsivenes...

Melanocortin neurons conserve body mass in hyper- or hypo-caloric conditions by conveying signals from nutrient sensors into areas of the brain governing appetite and metabolism. In mice, melanocortin-3 receptor (MC3R) deletion alters nutrient partitioning independently of hyperphagia, promoting accumulation of fat over muscle mass. Enhanced rhythms in insulin and insulin-responsive metabolic g...

One evolutionary adaptation in motor activity control of animals is the anticipation of food that drives foraging under natural conditions and is mimicked in laboratory with daily scheduled food availability. Food anticipation is characterized by increased activity a few hours before the feeding period. Here we report that 2-h food availability during the normal inactive phase of rats not only ...

The medial prefrontal cortex (mPFC) of the rat receives a prominent input from the ventral two thirds of the hippocampus, a structure important for spatial awareness, working memory and motivation. We recently found [Hok V, Lenck-Santini PP, Roux S, Save E, Muller RU, Poucet B. Goal-related activity in hippocampal place cells. J Neurosci 2007;27:472-82.] that neurones in the dorsal hippocampus ...