A novel circadian behavior rhythm in arrhythmic triple knockout mice revealed by constant light exposure.

The current model for autonomous circadian oscillation is based on the transcriptional-translational feedback loops of circadian genes. The deletion of one of the circadian genes and its paralogs leads to arrhythmicity. triple knockout ( KO) mice exhibit arrhythmic behavior in constant darkness.

Multiple oscillators underlie circadian food anticipation in mice.

Circadian pacemakers orchestrate behavioral and physiological rhythms, enabling organisms to anticipate daily reoccurring environmental events such as light and dark, temperature changes, and food availability. When nocturnal rodents are subjected to time-restricted feeding during the day, they typically display food anticipatory activity several hours before mealtime. Upon releasing mice to ad libitum feeding, this anticipatory activity is abolished immediately but, following food deprivation, reappears at approximately the same time.

A single incidental dark pulse during daytime attenuated food anticipatory behavior.

Using an open-source operant feeding device (FED3), we measured food-seeking nose poking behavior in mice. When the mice were exposed to 4 h restricted feeding at night, all mice exhibited robust food anticipatory nose poking starting ~4 h before scheduled mealtime. When the light-dark cycle was advanced by 6 h, mice exhibited two distinct bouts of anticipatory poking, one corresponding to actual mealtime which continued at the same time of day, and one corresponding to predicted mealtime which shifted parallel with the light-dark cycle.

Protocol to study circadian food-anticipatory poking in mice using the feeding experimentation device version 3.

Food-anticipatory nose poking is a unique food-seeking behavior driven by the food-entrainable oscillator. Here, we present a protocol to record a novel food-seeking nose poking behavior in mice under temporally restricted feeding followed by food deprivation using the open-source feeding experimentation device version 3 (FED3). We describe steps for setting up the FED3 and cage, training, and habituation.