Alterations in brain network functional connectivity and topological properties in DRE patients.

Objective: The study aimed to find the difference in functional network topology on interictal electroencephalographic (EEG) between patients with drug-resistant epilepsy (DRE) and healthy people. Methods: We retrospectively analyzed the medical records as well as EEG data of ten patients with DRE and recruited five sex-age-matched healthy controls (HC group). Each participant remained awake while undergoing video-electroencephalography (vEEG) monitoring. After excluding data that contained abnormal discharges, we screened EEG segments that were free of artifacts and put them together into 20-min segments. The screened data was bandpass filtered to different frequency bands (delta, theta, alpha, beta, and gamma). The weighted phase lag index (wPLI) and the network properties were calculated to evaluate changes in the topology of the functional network. Finally, the results were statistically analyzed, and the false discovery rate (FDR) was used to correct for differences after multiple comparisons. Results: In the full frequency band (0.5-45 Hz), the functional connectivity in the DRE group during the interictal period was significantly lower than that in the HC group (p < 0.05). Compared to the HC group, in the full frequency band, the DRE group exhibited significantly decreased clustering coefficient (CC), node degree (D), and global efficiency (GE), while the characteristic path length (CPL) significantly increased (p < 0.05). In the sub-frequency bands, the functional connectivity of the DRE group was significantly lower than that of the HC group in the delta band but higher in the alpha, beta, and gamma bands (p < 0.05). The statistical results of network properties revealed that in the delta band, the DRE group had significantly decreased values for D, CC, and GE, but in the alpha, beta, and gamma bands, these values were significantly increased (p < 0.05). Additionally, the CPL of the DRE group significantly increased in the delta and theta bands but significantly decreased in the alpha, beta, and gamma bands (p < 0.05). Conclusion: The topology structure of the functional network in DRE patients was significantly changed compared with healthy people, which was reflected in different frequency bands. It provided a theoretical basis for understanding the pathological network alterations of DRE.

Research Trends and Hot Spots of Allopregnanolone Research in the Last 20 Years: A Bibliometric Analysis.

Background: Allopregnanolone is a kind of neuroactive steroid or neurosteroid in the central nervous system that acts as an endogenenous GABAA receptor positive modulator. However, at present, no comprehensive bibliometric analysis regarding allopregnanolone research is available. In our study, we intend to analyze the research trends and hot spots related to allopregnanolone in the past 20 years. Methods: We searched for allopregnanolone related articles and reviews between 2004 and 2023 from the Web of Science Core Collection database. Then, the bibliometric analysis was conducted using VOSviewer, CiteSpace, Microsoft Excel 2019, as well as the online bibliometric analysis platform (http://bibliometric.com/). Results: A total of 1841 eligible publications were identified. The number of annual publications and citations was generally on the rise. Among countries, the United States ranked first in overall publications, citations, international cooperation, and the number of research institutions. The University of North Carolina was the most active institution, conducting numerous preclinical and clinical work that focusing on allopregnanolone treatment for diverse psychiatric or neurologic disorders. As for authors, Dr. Frye CA, Morrow AL, and Pinna G were identified as the top three prolific scholars due to their great publications and citations. Based on the publication clusters and citation bursts analysis, the keyword co-occurrence network, the strongest citation bursts, and co-cited references analysis, the hot spots in recent years included "depression", "postpartum depression", "GABAA receptor", and so on. Conclusion: Allopregnanolone is still a popular area of research, and the United States leads the way in this area. Dr. Frye CA, Morrow AL, Pinna G, and their teams contributed greatly to the mechanism study and translation study of allopregnanolone. The use of allopregnanolone for the treatment of psychiatric or neurologic disorders, especially postpartum depression, is the current hot spot. However, the underlying mechanisms of anti-depression are still not clear, deserving more in-depth research.

Brain functional connectivity and network characteristics changes after vagus nerve stimulation in patients with refractory epilepsy.

Objective: This study aims to investigate the impact of vagus nerve stimulation (VNS) on the connectivity and small-world metrics of brain functional networks during seizure periods. Methods: Ten refractory epilepsy patients underwent video encephalographic monitoring before and after VNS treatment. The 2-min electroencephalogram segment containing the ictal was selected for each participant, resulting in a total of 20 min of seizure data. The weighted phase lag index (wPLI) and small-world metrics were calculated for the whole frequency band and different frequency bands (delta, theta, alpha, beta, and gamma). Finally, the relevant metrics were statistically analyzed, and the false discovery rate was used to correct for differences after multiple comparisons. Results: In the whole band, the wPLI was notably enhanced, and the network metrics, including degree (D), clustering coefficient (CC), and global efficiency (GE), increased, while characteristic path length (CPL) decreased (P < 0.01). In different frequency bands, the wPLI between the parieto-occipital and frontal regions was significantly strengthened in the delta and beta bands, while the wPLI within the frontal region and between the frontal and parieto-occipital regions were significantly reduced in the beta and gamma bands (P < 0.01). In the low-frequency band (<13 Hz), the small-world metrics demonstrated significantly increased CC, D, and GE, with a significantly decreased CPL, indicating a more efficient network organization. In contrast, in the gamma band, the GE decreased, and the CPL increased, suggesting a shift toward less efficient network organization. Conclusion: VNS treatment can significantly change the wPLI and small-world metrics. These findings contribute to a deeper understanding of the impact of VNS therapy on brain networks and provide objective indicators for evaluating the efficacy of VNS.