Altered Functional Connectivity Patterns of the Insular Subregions in Psychogenic Nonepileptic Seizures

Neuroimaging studies have demonstrated that psychogenic nonepileptic seizures (PNES) are characterized by unstable cognitive-emotional and motor system, which is engaged in hyperactivity of limbic regions and sensorimotor area. The insula, which is a part of the limbic system, includes various subregions with some distinct connectivity patterns separately. However, whether these insular subregions show different connectivity patterns respectively in PNES remains largely unknown. We aimed to investigate the functional connectivity (FC) of insular subregions in PNES and extend the understanding of the complex pathophysiological mechanisms of this disease. A resting-state FC based on the insular subregions were conducted in 18 patients and 20 healthy controls. We examined the differences in FC values between PNES patients and controls using two sample t test. Our results showed patients had significantly stronger FC between insular subregions and sensorimotor network, lingual gyrus, superior parietal gyrus and putamen, which suggested a hyperlink pattern of insular subregions involved in abnormal emotion regulation, cognitive processes and motor function in PNES. Pearson correlation analysis between the mean FC values within abnormal regions and the frequency of PNES further indicated PNES exhibited abnormal functional organization whose stressful emotion of patients have great direct influence on their motor functions. The differentially impaired functional connectivity patterns of insular subregions might provide new insights into the complex neurological mechanism of PNES.