Altered Neural Processing of Interoception in Patients With Functional Neurological Disorder: A Task-Based fMRI Study.

Objective: Research suggests that disrupted interoception contributes to the development and maintenance of functional neurological disorder (FND); however, no functional neuroimaging studies have examined the processing of interoceptive signals in patients with FND.

Methods: The authors examined univariate and multivariate functional MRI neural responses of 38 patients with mixed FND and 38 healthy control individuals (HCs) during a task exploring goal-directed attention to cardiac interoception-versus-control (exteroception or rest) conditions. The relationships between interoception-related neural responses, heartbeat-counting accuracy, and interoceptive trait prediction error (ITPE) were also investigated for FND patients.

Results: When attention was directed to heartbeat signals versus exteroception or rest tasks, FND patients showed decreased neural activations (and reduced coactivations) in the right anterior insula and bilateral dorsal anterior cingulate cortices (among other areas), compared with HCs. For FND patients, heartbeat-counting accuracy was positively correlated with right anterior insula and ventromedial prefrontal activations during interoception versus rest. Cardiac interoceptive accuracy was also correlated with bilateral dorsal anterior cingulate activations in the interoception-versus-exteroception contrast, and neural activations were correlated with ITPE scores, showing inverse relationships to those observed for heartbeat-counting accuracy.

Conclusions: This study identified state and trait interoceptive disruptions in FND patients. Convergent between- and within-group findings contextualize the pathophysiological role of cingulo-insular (salience network) areas across the spectrum of functional seizures and functional movement disorder. These findings provide a starting point for the future development of comprehensive neurophysiological assessments of interoception for FND patients, features that also warrant research as potential prognostic and monitoring biomarkers.