Abstract
The detection of environmental temperature and regulation of body temperatures are integral determinants of behavior for all animals. These functions seemingly become less efficient in aged animals, especially during exposure to cold environments. We reasoned that a clearer understanding of the underlying molecular and cellular mechanisms that alter set point temperatures during aging could reveal insights into why such age-related changes occur. Here, we identified an age-related change in the temperature preference of adult fruit flies, which results from a shift in the relative contributions of two parallel mushroom body (MB) circuits—the β′ and β systems. The β′ circuit primarily controls cold avoidance through dopamine signaling in young flies, whereas the β circuit increasingly contributes to cold avoidance as adult flies age. The restoration of cold sensitivity in aged flies by elevating dopamine levels in β′ afferent neurons suggests that the alteration of cold avoidance behavior with aging is functionally reversible. These findings add to the diverse functions of the MB subregions and provide a framework to investigate how molecules and neural circuits modulate homeostatic alterations during the course of senescence.