Sensory-specific Appetition: Postingestive Detection of Glucose Rapidly Promotes Continued Consumption of a Recently Encountered Flavor

It is generally thought that macronutrients stimulate intake when sensed in the mouth (e.g., sweet taste) but as food enters the GI tract its effects become inhibitory, triggering satiation processes leading to meal termination. Here we report experiments extending recent work (see [1]) showing that under some circumstances nutrients sensed in the gut produce a positive feedback effect, immediately promoting continued intake. In one experiment, rats with intragastric (IG) catheters were accustomed to consuming novel flavors in saccharin daily while receiving water infused IG (5 ml/15 min). The very first time glucose (16% w/w) was infused IG instead of water, intake accelerated within 6 mins of infusion onset and total intake increased 29% over baseline. Experiment 2 replicated this stimulatory effect with glucose infusion but not fructose nor maltodextrin. Experiment 3 showed the immediate intake stimulation is specific to the flavor accompanying the glucose infusion. Rats were accustomed to flavored saccharin being removed and replaced with the same or a different flavor. When glucose infusion accompanied the first bottle, intake from the second bottle was stimulated only when it contained the same flavor, not when the flavor switched. Thus we confirm not only that glucose sensed postingestively can have a rapid, positive feedback effect ('appetition' as opposed to 'satiation') but that it is sensory-specific, promoting continued intake of a recently encountered flavor. This sensory specific motivation may represent an additional psychobiological influence on meal size, and further, has implications for the mechanisms of learned flavor-nutrient associations.

Writing the Unspeakable: an Ethical Approach to a Traumatized Narrative

This project uses the works of contemporary author Tim O’Brien, whose fiction often performs the trauma of the Vietnam War, to explore new ways of encountering the traumatized text. Informed by Emmanuel Levinas’s ethics of the face, and Sigmund Freud’s and Dominick LaCapra’s work on the narratology of the melancholic and the mourner, I consider the different ways we respond to the suffering Other and explore the paradox that through reading a traumatized narrative empathically we may come face-toface, as it were, with the suffering Other. If this is indeed the case, I reason, then the obligations that are due to the Other are also due to the text itself.