Neural ensemble recordings from central gustatory-reward pathways in awake and behaving animals
The mammalian gustatory system participates in the detection and discrimination of intraoral stimuli, allowing for the selection of nutrients and rejection of toxic compounds. However, the sensory percept of a substance that is placed in the mouth does not depend solely on its taste. The olfactory and somatosensory systems discriminate odor, texture, and temperature, which participate, with taste, in the unitary perception of flavor (Small and Prescott 2005). Flavor is a central contributor in the decision making relative to ingestive behavior. However, feeding decisions are made in specific physiological contexts and, therefore, are not entirely dependent on sensory experience. We know today that the central nervous system (CNS) detects a multitude of peripheral neural and humoral signals that reflect gastrointestinal status and current energy needs, availability, and stores (Broberger 2005). The regulation of energy homeostasis and maintenance of stable body weight depend on the integration of these signals and the ability to respond adequately through the modulation of both energy expenditure and food intake (Schwartz and Porte 2005).