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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, postcentral 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., Competing Interests: Declaration of Competing Interest All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The neuropathic pain (NPP) after brachial plexus avulsion (BPA) is common and difficult to cure, and thalamus and postcentral gyrus have been accepted to be the key nodes of mechanisms and pathways for pain. However, little attention has been paid on the thalamus-postcentral gyrus functional connectivity changes in NP patients after BPA., Methods: Eighteen patients with NPP after BPA and twenty age and gender matched healthy controls were enrolled and underwent resting-state functional MRI (rs-fMRI) scans in this study. The Pearson's r-value of functional connection (bilateral thalamus and postcentral gyrus as regions of interest) was generated and examined using two sample t-test. The linear regression analysis was used to select possible related factors, and multiple linear regression of the possible predictors was used to identify the variables that significantly predicted Visual Analogue Score (VAS)., Results: The standardized Pearson r-values of the left thalamus-right thalamus, left thalamus-left postcentral gyrus, left thalamus-right postcentral gyrus, right thalamus-left postcentral gyrus and right thalamus-right postcentral gyrus in the control group were 0.759 ± 0.242, 0.358 ± 0.297, 0.383 ± 0.270, 0.317 ± 0.295 and 0.333 ± 0.304, respectively. And the corresponding standardized Pearson r-values in patients group were 0.510 ± 0.224,0.305 ± 0.212,0.281 ± 0.225,0.333 ± 0.193 and 0.333 ± 0.210, respectively. The functional connectivity strength of the left thalamus-right thalamus in control group was significantly higher than that in the patients group (P < 0.05). Linear regression analysis showed that the functional connectivity strength of the left thalamus-right thalamus was negatively correlated with the patients' VAS score (P < 0.05)., Conclusions: NPP patients after BPA had a significant pain-related bilateral thalamus functional connection reorganization, with the purpose to limit the pain signal inputs within the unilateral cerebral hemisphere., (Copyright © 2023 Elsevier B.V. All rights reserved.)