Session: 2

PS2-01 | Motivation for food reward is involved in food anticipatory activity in mice under restricted feeding conditions

Julieta Acosta

Laboratorio de Cronobiología, Universidad Nacional de Quilmes.

In mammals, the circadian system modulates several behavioral and physiological processes, including the response to natural rewards such as food. On the other hand, when food is temporally restricted, animals display an anticipatory food activity (FAA) that is controlled by a food-entrainable oscillator (FEO).
We have previously shown that mice under a 12:12 light/dark (LD) cycle exhibited a diurnal rhythm in motivation for food reward, becoming more motivated during the night (active phase). This rhythm was also evident under constant dark (DD) conditions, indicating the endogenous nature of this modulation.
In this work, we present evidence that motivation for food reward is involved in FAA regardless of mice being food restricted during the day or night phases of the LD cycle. Mice in a restricted feeding (RF) protocol under a 12:12 LD cycle were allowed to consume food only 3 hours during daytime or nighttime. Then, motivation behavior was assayed – through the progressive ratio (PR) schedule – in two different time points: during FAA (i.e, two hours before food availability) and in the opposite phase to wich the RF was carried out. Our results show that mice are highly motivated to work for food reward when FAA is present regardless of the time of day. These results suggest that, during FAA, components related to reward pathways might be activated and consecuently generate an increase in motivation bypassing circadian time cues.