Mechanisms of conditioned meal initiation.
Three experiments investigate behavioral and biological mechanisms of meal initiation controlled by learning. Animals were classically conditioned to initiate a meal in response to a conditioned stimulus paired with food. We demonstrate that: a) aversion to the signalled food markedly reduces consumption but has no effect on eating-related behaviors anticipatory to ingestion; b) naloxone reduces the amount eaten but has no impact on food-anticipatory behaviors; c) dopamine antagonism attenuates food-anticipatory behaviors without influencing amount eaten, and d) satiety signals arising from food in the gut reduce both food-anticipatory behaviors and amount eaten. These results demonstrate that anticipatory (appetitive) and consummatory components of meal initiation can be dissociated and are controlled by different biological mechanisms. Cues conditioned to food elicit eating by selectively activating appetitive systems. The implications of the appetitive/consummatory distinction for contemporary theories of meal initiation are discussed.
Weingarten
H P
HP
Department of Psychology, McMaster University, Hamilton, Ontario, Canada.
Martin
G M
GM
D000818:Animals; D001066:Appetite / Q000187:drug effects / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D003213:Conditioning, Psychological / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D005475:Flupenthixol / Q000494:pharmacology; D006815:Hunger / Q000502:physiology; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D012527:Satiation / Q000502:physiology*; D013649:Taste
D009270:Naloxone; D005475:Flupenthixol