Vagal Afferent Signaling and the Integration of Direct and Indirect Controls of Food Intake

Excerpt

In terms of individual survival, feeding arguably is the most important behavior in which animals engage, because all physiological functions, including other behaviors, depend on the energy and nutrients obtained only through food intake. Consequently, control of feeding behavior is of high priority for the brain, the organ of behavior. Indeed, it is tempting to argue that selective pressures driving the evolution of ganglia or brains near the oral opening of the digestive system included efficient detection, pursuit, capture, and ingestion of food. Moreover, the anatomical concentration of sensory inputs in ganglia or brain facilitates network interactions between modalities that represent distinct qualities of food, such as chemical composition (taste) and bulk or mass (gut stretch). The integration of afferent information from disparate peripheral sources is the foundation for control of food intake. For a concise review of nervous system and behavioral evolution see Dethier and Stellar (1964).