Amino acids, taste circuits, and feeding behavior in Drosophila: towards understanding the psychology of feeding in flies and man.

Feeding can be regulated by a variety of external sensory stimuli such as olfaction and gustation, as well as by systemic internal signals of feeding status and metabolic needs. Faced with a major health epidemic in eating-related conditions, such as obesity and diabetes, there is an ever increasing need to dissect and understand the complex regulatory network underlying the multiple aspects of feeding behavior. In this minireview, we highlight the use of Drosophila in studying the neural circuits that control the feeding behavior in response to external and internal signals. In particular, we outline the work on the neuroanatomical and functional characterization of the newly identified hugin neuronal circuit. We focus on the pivotal role of the central nervous system in integrating external and internal feeding-relevant information, thus enabling the organism to make one of the most basic decisions - to eat or not to eat.