Altered intrinsic brain activity in patients with neuropathic pain after brachial plexus avulsion

Objective: This study aimed to investigate brain activity changes in patients suffering from neuropathic pain (NP) following brachial plexus avulsion (BPA).Methods: Fifteen patients with NP following BPA and eight healthy participants (HP) were recruited for this study. All participants underwent examination using resting-state functional MRI. The amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) were calculated and compared between the BPA group, left-BPA subgroup, right-BPA subgroup, and the HP group using independent samples t-tests.Results: In the BPA group, there were notable increases in ALFF/ReHo observed in the left rolandic operculum, insula, and supramarginal gyrus, while decreases were observed in the left paracentral lobule, fusiform gyrus, calcarine fissure and surrounding cortex, lingual gyrus, precuneus, as well as the bilateral anterior/median cingulate and paracingulate gyri, supplementary motor area, and cerebellum. In the left-BPA subgroup, elevated ALFF/ReHo levels were identified in the left middle/inferior frontal gyri, rolandic operculum, and supramarginal gyrus, with corresponding decreases in the left calcarine fissure and surrounding cortex, inferior occipital gyrus, fusiform gyrus, lingual gyrus, as well as the bilateral anterior/median cingulate and paracingulate gyri, post-central gyri, supplementary motor area, paracentral lobules, and cerebellum. The right-BPA subgroup displayed increased ALFF/ReHo in the left frontal lobe, rolandic operculum, insula, fusiform gyrus, and lingual gyrus, as well as the right cerebellum. Conversely, decreases in ALFF/ReHo were observed in the bilateral anterior/median cingulate and paracingulate gyri, calcarine fissure and surrounding cortex, cuneus, and occipital lobes.Conclusions: The NP after BPA caused spontaneous activity changes in brain regions associated with linguistic, visual, somatosensory, and motor coordination and processing function. The majority of these abnormal areas were situated in the left cerebral hemisphere, while the effect of cingulate gyri and cerebellum seemed to be bilateral.