Layers of signals that regulate appetite

• Published in: Current opinion in neurobiology Vol. 64; pp. 79 - 88
• Main Authors: Zimmerman, Christopher A, Knight, Zachary A
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2020
• Subjects: Appetite; Brain; Eating; Hunger; Neurons; Thirst
• ISSN: 0959-4388; 1873-6882
• DOI: 10.1016/j.conb.2020.03.007

•Eating and drinking trigger layers of pre-gastric and gastrointestinal feedback.•These signals are generated by molecularly distinct cell types in peripheral tissues.•Vagal feedback from the gut drives dopamine release and reinforcement learning.•AgRP neurons receive signals reflecting future, current, and past feeding behavior.•Thirst neurons integrate feedback signals from the oropharynx, gut, and blood. All meals come to an end. This is because eating and drinking generate feedback signals that communicate to the brain what and how much has been consumed. Here we review our current understanding of how these feedback signals regulate appetite. We first describe classic studies that surgically manipulated the gastrointestinal tract and measured the effects on behavior. We then highlight recent experiments that have used in vivo neural recordings to directly observe how ingestion modulates circuit dynamics in the brain. A general theme emerging from this work is that eating and drinking generate layers of feedback signals, arising sequentially from different tissues in the body, that converge on individual neurons in the forebrain to regulate hunger and thirst.