Interoceptive Attentiveness: Evidence for Neurofunctional Correlates from an EEG Source Localization Study

Objective: Since seminal work by Sherrington, the term interoception refers to the ability to sense modifications of internal bodily states as opposed to the ability to sense stimuli coming from outside the body itself. Despite conceptual changes regarding the afferent signals subserving this type of inner perception, the core of this definition is still valid and widely accepted. The critical contribution of internal state perception to self-regulation as well as higher-order cognitive processes has led to the development of psychometric and observational measures trying to capture individual interoceptive skills, focusing especially on the ability to orient attention to internal sensations. Nonetheless, despite growing interest in interoceptive attention (IAtt), little is known about neurofunctional correlates of our ability to redirect attention to internal sensations and consciously process them, as well as on potential objective biomarkers of IAtt performance. Participants and Methods: This study included 36 volunteers who were asked to complete a heart-beat counting task (HCT), a common IAtt task. During both resting-state and HCT, central electrophysiological (EEG, 32 electrodes) and cardiovascular activity (ECG, I lead) were recorded. eLORETA was used to estimate both task-related and resting-state intracortical sources of EEG signals. Statistical non-parametric mapping (SnPM) was used to draw and investigate contrast statistical maps between rest- and task-related cortical current density. Results: Contrast analyses comparing HCT and resting revealed higher Alpha frequency current density estimates during the task, with primary cortical seed in the right parahippocampal gyrus. Regression analyses of the relationship between IAtt scores and task-related changes in intracortical current density during HCT revealed a positive relationship for the Beta frequency bands with primary cortical seeds in the cingulate gyrus and insula. Conclusions: Findings add to available literature by further specifying the electrophysiological signature of interoceptive attentiveness, and suggest specific electrophysiological markers as objective measures of individual IAtt skills.