Interoceptive Accuracy Moderates the Glycaemic, Autonomic and Subjective Response to a Glucose Load: A Test of the Predictive Coding Framework.

Recently, interoception and homeostasis have been described in terms of predictive coding and active inference. Afferent signals update prior predictions about the state of the body and stimulate autonomic mediation of homeostasis. Performance on tests of interoceptive accuracy (IAc) may indicate an individual’s ability to flexibly assign precision to interoceptive signals, thus determining the relative influence of ascending signals and prior beliefs. Accordingly, individuals with high IAc should be more able to counter-regulate during the postprandial period. Eighty females were randomly allocated to consume glucose, an artificially sweetened drink, water or no drink. Before, and thirty minutes after a drink, IAc, heart rate and blood glucose were measured, and participants rated their hunger thirst and mood. A higher IAc was related to lower blood glucose levels, a decline in anxiety, and a higher heart rate, after consuming glucose. A higher IAc also resulted in a larger decline in hunger if they consumed either glucose or sucralose. These data provide the first empirical verification of the role of active inference in interoception and homeostasis. In addition, the approach highlights the utility of indices of interoceptive accuracy as composite markers of phenotypic flexibility.