A Bayesian computational model reveals a failure to adapt interoceptive precision estimates across depression, anxiety, eating, and substance use disorders
Authors: Smith Ryan , Kuplicki Rayus , Feinstein Justin , Forthman Katherine L. , Stewart Jennifer L. , Paulus Martin P. ,   Tulsa 1000 investigators, Khalsa Sahib S. 
Published: June 2020

Recent neurocomputational theories have hypothesized that abnormalities in prior beliefs and/or the precision-weighting of afferent interoceptive signals may facilitate the transdiagnostic emergence of psychopathology. Specifically, it has been suggested that, in certain psychiatric disorders, interoceptive processing mechanisms either over-weight prior beliefs or under-weight signals from the viscera (or both), leading to a failure to accurately update beliefs about the body. However, this has not been directly tested empirically. To evaluate the potential roles of prior beliefs and interoceptive precision in this context, we fitted behavior in a transdiagnostic patient population on an interoceptive awareness (heartbeat tapping) task to a Bayesian computational model. Modeling revealed that, during an interoceptive perturbation condition (inspiratory breath-holding during heartbeat tapping), healthy individuals (N=52) assigned greater precision to ascending cardiac signals than individuals with symptoms of anxiety (N=15), depression (N=69), co-morbid depression/anxiety (N=153), substance use disorders (N=131), and eating disorders (N=14) – who failed to increase their precision estimates from resting levels. In contrast, we did not find strong evidence for differences in prior beliefs. These results provide the first empirical computational modeling evidence of a selective dysfunction in adaptive interoceptive processing in psychiatric conditions, and lay the groundwork for future studies examining how reduced interoceptive precision influences body regulation and interoceptively-guided decision-making.

Author Summary

Interoception is the process by which the nervous system senses the internal state of the body. It provides the brain with important information to adaptively guide the regulation of both internal body states and behavior. Interoceptive dysfunction is thought to play a role in multiple psychiatric disorders. Theoretical models propose that the computational mechanisms of interoceptive dysfunction are caused by overly precise prior beliefs about body states (“hyperprecise priors”) or underestimates of the reliability of the information carried by ascending signals from the body (“low sensory precision”). Our empirical approach tested for evidence of these mechanisms across several psychiatric disorders, using a computational model of perception during performance of a heartbeat perception task. We found evidence of low sensory precision within individuals with anxiety, depression, eating disorders, and/or substance use disorders, relative to healthy individuals. This difference occurred only during a breath-holding condition designed to enhance heartbeat signals. We did not find evidence for hyperprecise priors in the patient groups. The data from this study support the argument for computational mechanisms of interoceptive dysfunction across several psychiatric disorders, and suggests that these conditions may be characterized by an inability to adjust sensory precision when signals from the body change.