Finding the Food Entrainable Oscillator: Isolating the Circadian Pacemaker of Food Anticipation

Animals under temporally restricted meal schedules exhibit food anticipatory activity (FAA). Previous investigations conclude that FAA is regulated by a central network of circadian mechanisms, the food entrainable oscillator (FEO), whose neural correlates remain unknown. This study used an intrinsic property of circadian pacemakers, the ability to continue oscillating after removal of the zeitgeber (cue), to isolate the circadian components of food anticipation. It was hypothesized that observation of anticipatory activation in central nuclei after food entrainment will elucidate the neural structures responsible for maintaining circadian oscillations of the FEO.;Keywords: Circadian Rhythms; Clock Genes; Food Anticipatory Activity (FAA); Food Entrainable Oscillator (FEO); Ghrelin Receptor (GHS-R); Light/Dark Cycle (L:D); Light Entrainable Oscillator (LEO); Meal Anticipation; Restricted Feeding Schedule (RF); Zeitgeber.;A second study hypothesized that ghrelin, an orexigenic hormone produced in the stomach whose secretion rises pre-prandially and quickly subsides after the presentation of a meal, serves as an important signal for the entrainment and expression of FAA. Mice expressing a genetic knock out of the ghrelin receptor gene were compared to their wild-type counterparts in order to examine this process and its neural correlates.