Abstract
Although various imaging studies have focused on detecting the cerebral function underlying psychogenic non-epileptic seizures (PNES), the nature of PNES remains poorly understood. In this study, we combined the resting state fMRI with fractional amplitude of low-frequency fluctuations (fALFF) and functional connectivity based on the seed voxel linear correlation approach to examine the alterations of regional and inter-regional network cerebral functions in PNES. A total of 20 healthy controls and 18 patients were enrolled. The PNES patients showed significantly increased fALFF mainly in the dorsolateral prefrontal cortex (DLPFC), parietal cortices, and motor areas, as well as decreased fALFF in the triangular inferior frontal gyrus. Thus, our results add to literature suggesting abnormalities of neural synchrony in PNES. Moreover, PNES exhibited widespread inter-regional neural network deficits, including increased (DLPFC, sensorimotor, and limbic system) and decreased (ventrolateral prefrontal cortex) connectivity, indicating that changes in the regional cerebral function are related to remote inter-regional network deficits. Correlation analysis results revealed that the connectivity between supplementary motor area and anterior cingulate cortex correlated with the PNES frequency, further suggesting the skewed integration of synchronous activity could predispose to the occurrence of PNES. Our findings provided novel evidence to investigate the pathophysiological mechanisms of PNES.
Highlights
Previous studies have demonstrated that Psychogenic non-epileptic seizures (PNES) exhibit altered functional connections in the prefrontal and parietal cortices and SMN4,17; we hypothesized that the patients with PNES would show abnormal fractional ALFF (fALFF) in these regions
Even if abnormal fALFF is detected in PNES, we question that whether the specific regional signal fluctuation amplitude abnormalities are associated with potential connectivity alterations of that local activity across brain regions
Recent studies have observed overlaps between abnormalities in regional amplitude of low frequency fluctuations (ALFF) and FC in several brain regions in affective disorder[19], stuttering[20], post-traumatic stress disorder[21] and schizophrenia[22]. These studies suggested a relationship between ALFF and FC; both the regional cerebral function and functional integration have not been investigated in patients with PNES
Summary
Even if abnormal fALFF is detected in PNES, we question that whether the specific regional signal fluctuation amplitude abnormalities are associated with potential connectivity alterations of that local activity across brain regions. Recent studies have observed overlaps between abnormalities in regional ALFF and FC in several brain regions in affective disorder[19], stuttering[20], post-traumatic stress disorder[21] and schizophrenia[22] These studies suggested a relationship between ALFF and FC; both the regional cerebral function and functional integration have not been investigated in patients with PNES. The fALFF measures the regional signals change of spontaneous activity within a specific frequency range, while the FC reflects the level of integration of that local activity across brain regions, which can provide new insights to the pathophysiological mechanism underlying PNES. We further examined the correlations between the fALFF and FC values and the frequency of PNES
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