Extended Data Fig. 11: Separate circuits for the oral and gastrointestinal control of ingestion.

a, Food intake generates both fast orosensory and slower GI signals that feed back to the cNTS to modulate appetite. Orosensory signals, including taste, preferentially target PRLH neurons, which are phasically activated during bouts of ingestion and function to acutely restrain bout size, thereby slowing down the pace of ingestion. Mechanosensory signals from the GI tract preferentially target GCG neurons, which show sustained activity during feeding and transmit a long-lasting satiety signal that delays reinitiation of feeding. b, Our data suggest that appetitive tastes, such as sweet and fat, are used by different brain systems for opposing purposes. Activation of well-known gustatory reward pathways by palatable tastes functions to increase food consumption. In parallel, activation of PRLH neurons by palatable tastes feeds back to slow down the rate of ingestion by limiting bout size. Although it may seem counterintuitive that palatable tastes would be used by some brain systems to inhibit ingestion, the existence of this mechanism is supported by several lines of evidence. This evidence includes the results of sham feeding studies in rats^41,42, which showed that a pre-gastric signal (likely involving taste) slows down ingestion.