Multiple processes in the short-term reduction of palatability in mice

Abstract

Time since recent consumption is an important factor in determining eating behaviour, due to the occurrence of short-term adaptation. This adaptation effect is seen in the amount consumed being reduced and is also associated with a corresponding reduction in palatability of the food recently consumed. In this series of experiments the time course of this short-term adaptation effect is investigated, using mean lick cluster size as a measure of palatability during consumption of sucrose solution in mice. It is firstly demonstrated that there is a reduction in the total number of licks as well as the mean lick cluster size after recent consumption of a sucrose solution. This is found to occur rapidly with consumption and also to recover over short time periods between feeding opportunities. However rather than there being a single short-term adaptation effect, there is found to be an inverted U-shape function of palatability with time since consumption. Two experimental confounds that may have resulted in the secondary decline in palatability are subsequently investigated. Firstly a frustrative non-reward account is investigated, before differing time in the context before consumption is also tested. As the secondary decline in palatability remains despite these factors being accounted for, it is concluded that there are two short-term adaptation processes after recent consumption of a sucrose solution.