Postingestive controls of carbohydrate-based food preferences: Effect of site and delay of nutrient infusions.
Item
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Title
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Postingestive controls of carbohydrate-based food preferences: Effect of site and delay of nutrient infusions.
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Identifier
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AAI9618060
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identifier
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9618060
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Creator
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Drucker, Debra Blusk.
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Contributor
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Adviser: Anthony Sclafani
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Date
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1996
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Experimental | Psychology, Physiological | Health Sciences, Nutrition
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Abstract
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The physiological controls which mediate the acquisition of food preferences are not well understood. This dissertation research investigated how the gastrointestinal site and delay of carbohydrate delivery influence the development of flavor preferences in rats. The conditioned flavor preference procedure was used in all experiments. On alternate training days, rats consumed nonnutritive CS+ and CS{dollar}-{dollar} cue flavors which were paired with carbohydrate and water infusions, respectively. On test days, rats were given a choice between the two cue flavors without infusions, and preferences were assessed. In Experiment 1, the preferences conditioned by intragastric (IG) and intraduodenal (ID) glucose infusions were compared in two groups of rats. Strong and comparable flavor preferences were conditioned by IG and ID glucose infusions. Experiment 2A examined whether the actions of glucose in the stomach alone are sufficient to condition flavor preferences. When IG glucose infusions were restricted to the stomach during training by inflation of a pyloric cuff, preferences were not obtained. Preferences were observed in a control group that was able to experience the post-gastric effects of the IG glucose infusions. Experiment 2B demonstrated that pyloric cuff inflation during conditioning does not prevent conditioning when the delayed post-gastric effects of the glucose were permitted following each conditioning session. If preferences are mediated by post-gastric effects, conditioning must be able to withstand delays. Experiment 3 examined preference conditioning with delays of 2.5, 10, 30 and 60 minutes between cue flavor consumption and IG 8% glucose infusions. The strength of the preferences decreased as the delay interval increased; with a 60 minute delay preferences were not exhibited. To determine whether increasing the magnitude of reinforcement promotes conditioning with a 60 minute delay, Experiment 4 compared the preferences conditioned by IG infusions of 8% and 16% Polycose. Preferences were conditioned by both concentrations of Polycose, although, 16% Polycose tended to condition stronger and more reliable preferences. Taken together, the findings suggest that preference conditioning is mediated by the post-gastric actions of carbohydrates which may occur following a delay. Possible mechanisms for long-delay learning and communication between gut and brain were discussed.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
