Brain connectivity最新文献

Background: Numerous neuroimaging studies have revealed abnormal brain function in patients with herpes zoster (HZ) and postherpetic neuralgia (PHN). However, few studies have focused on the alterations of intrinsic degree centrality (DC) in the transition process from the HZ to the PHN. Materials and Methods: Resting-state functional MRI (rs-fMRI) data from 27 patients with PHN, 24 patients with HZ, and 21 healthy controls (HCs) were acquired. DC based on rs-fMRI was used to explore specific brain functional abnormalities in these participants. Results: Compared with HCs, patients with HZ presented decreased DC values in the right superior frontal gyrus, right cingulate gyrus, bilateral inferior parietal lobule (IPL), bilateral precuneus, and right paracentral lobule. Compared with HCs, patients with PHN also exhibited decreased DC values in the bilateral IPL. However, no regions with significant DC value changes were found between the HZ and PHN groups. Conclusions: These results suggest that decreased DC of the IPL is associated with the underlying neural mechanisms of the HZ and PHN stages and may represent a potential biomarker or intervention target candidate that needs further longitudinal confirmation.

Introduction: Research on brain functional connectivity often relies on intraindividual moment-to-moment correlations of functional activity, typically using functional MRI (fMRI). Interindividual correlations are also employed in data from fMRI and positron emission tomography. Many studies have not specified tasks during scanning, keeping participants in an implicit "resting" condition. This lack of task specificity raises questions about how different tasks impact interindividual correlation estimates. Methods and Results: In our analysis of fMRI data from 100 unrelated participants scanned during seven tasks and in a resting state, we calculated regional homogeneity (ReHo) for each task as a regional measure of brain function. We found that changes in ReHo due to tasks were relatively small compared with its variations across brain regions. Cross-region variations of ReHo were highly correlated among tasks. Similarly, whole-brain interindividual correlation patterns were remarkably consistent across the tasks, showing correlations greater than 0.78. Changes in interindividual correlations between tasks were primarily driven by connectivity in the visual, somatomotor, and default mode networks, as well as the interactions between them. Conclusions: These subtle yet statistically significant differences in functional connectivity may be linked to specific brain regions associated with the studied tasks. Future studies should consider task design when exploring interindividual connectivity in specific brain systems.

Introduction: Executive functions (EF) are cognitive processes supporting language and reading. Children with dyslexia show reading difficulties primarily due to phonological processing, with additional reported deficits in EF. This study aimed to determine the differences in EF involvement during written (reading) versus oral language (narrative) comprehension in children with dyslexia versus typical readers neurobiologically and behaviorally. Methods: Reading, language, and EF behavioral measures and functional MRI data were collected from 55 typical readers (TR) and 65 English-speaking children with dyslexia ages 8-12 years during reading and narrative comprehension tasks. Differences within and between functional connectivity of EF and attention networks were calculated and then compared between groups and tasks using Fisher Z-transformation. Results: Children with dyslexia showed higher functional connectivity values in EF and attention networks in both reading and narrative comprehension tasks, whereas TR showed higher functional connectivity in narrative versus reading comprehension. Within groups, analysis showed higher functional connectivity within dorsal attention functional brain network (DAN) and between DAN-fronto-parietal (FP), cingulo-opercular (CO)-FP, and ventral attention functional brain network (VAN)-DAN, in the reading versus narrative comprehension task in the dyslexia group. TR showed higher functional connectivity within VAN, and between VAN-FP in the narrative compared to the reading comprehension tasks. Discussion: Children with dyslexia seem to greatly utilize EF and attention-related networks in narrative and reading comprehension tasks and demonstrate a greater network integration for the written versus oral comprehension task. TR, however, utilize these networks only during oral comprehension, which may point to a greater reliance on memory and processing effort in the absence of written information.

Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental condition that exhibits a wide range of clinical heterogeneity. This study aimed to explore the heterogeneity of ASD based on deviations in brain functional networks. Methods: Resting-state functional magnetic resonance imaging data from the Autism Brain Imaging Data Exchange database were analyzed in 105 children with ASD and 102 demographically matched typical controls (TC) children. Heterogeneity through discriminative analysis (HYDRA) was utilized to identify subtypes of ASD based on the degree centrality (DC) maps. Voxel-wise group comparisons were then performed between ASD subtypes and the TC group. The relationship between the altered DC and the symptom severity was finally analyzed for ASD subtypes using the multivariate support vector regression approach. Results: HYDRA identified three subtypes of ASD. Distinct DC alteration patterns were observed in brain regions including the fusiform gyrus, insula, and inferior frontal gyrus in ASD subtypes. Moreover, the altered DC values for ASD subtype 1 and subtype 3 can predict the restricted and repetitive behavior and social communication impairments in ASD, respectively. Conclusions: Our findings demonstrated the heterogeneity of brain functional networks in ASD and provided a promising way to explain the high heterogeneity of clinical symptoms and outcomes.

Background: The multilayer network framework has emerged as an innovative approach for analyzing electrophysiological networks, providing insights into complex neuronal interactions by integrating connectivity across different frequency bands in electroencephalography (EEG) and magnetoencephalography (MEG) data. Current Limitations: Traditionally, multilayer networks have treated canonical frequency bands (e.g., delta, theta, alpha, beta, gamma) as distinct layers. Recent findings could raise potential concerns regarding this approach, emphasizing the need to incorporate the distinction between periodic (oscillatory) and aperiodic (broadband) signal components. Conceptual Advance: Aperiodic signals may reflect excitation-inhibition balance and scale-free dynamics, while periodic signals capture oscillatory rhythms, both contributing uniquely to brain network interactions. A multilayer network framework in the current context could be applicable in the case of genuine coupling between these components, termed "aperiodic-to-periodic coupling." This necessitates novel connectivity metrics and analytical methods that can handle broadband data. Furthermore, challenges remain in decomposing these components in the time domain and developing robust metrics for broadband connectivity that account for signal leakage. Outlook: Addressing these issues will enhance multilayer frameworks, enabling better insights into brain network integrity, cognitive dysfunction, and neurological conditions.

Background: In anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis, the cerebellum, a characteristic brain region, exhibits abnormal functioning and structure. However, the relationship between resting-state activities in the cerebellar subregions and core symptoms of cognitive dysfunction is unclear. Methods: In this study, a total of 23 patients with anti-NMDAR encephalitis and 23 healthy controls were included, and 19 patients (mean age 30.05 ± 13.03 years) and 21 healthy controls (mean age 28.42 ± 9.47 years) were enrolled based on image quality and head movement. Seed-based functional connectivity (FC) analysis was used to investigate changes in FC of cerebellar subregions, and the association between changes in cerebellar subregion FC and cognitive dysfunction was explored in conjunction with cognitive scales. Results: Patients with anti-NMDAR encephalitis exhibited poorer cognitive performance than the healthy controls did. In the patient group, the FC between the right cerebellar Crus I and the left thalamus was significantly reduced and showed a negative correlation with disease duration (p < 0.05); however, it showed positive correlations with attention and information processing speed according to Symbol Digit Modalities Test (p < 0.01), as well as with verbal learning and memory (according to California Verbal Learning Test (CVLT; p < 0.05). The FCs between the left cerebellar Crus Ia and the right medial superior frontal gyrus, as well as between the left cerebellar Crus Ib and the right middle temporal gyrus, were decreased. The connectivity between the cerebellar vermis Crus II and the left putamen, along with the opercular part of the inferior frontal gyrus, showed a significant reduction. Decreased FC between the left cerebellar X lobule and the left putamen showed positive correlation with CVLT (p < 0.01). Conclusion: Cerebellar subregion and brain abnormalities FC in patients with anti-NMDAR encephalitis are linked to cognitive deficits. These results provide insights into the neurophysiological mechanisms underlying cognitive impairment in these patients.

Objective: Repetitive transcranial magnetic stimulation (rTMS) uses electromagnetic fields to induce electrical currents in the superficial cortex, and this electric signal is believed to propagate to functionally connected distal brain regions. We previously reported that rTMS targeting the postcentral gyrus affected resting-state functional connectivity with the posterior insula. The current study investigated whether rTMS targeting the postcentral gyrus would affect task-based functional connectivity (TBFC) with the posterior insula during a cognitive-affective distress task. Methods: Twenty-five healthy participants were assigned to 10 Hertz (Hz) (n = 13) or 1 Hz (n = 12) rTMS groups. Participants received five consecutive days of once-daily rTMS and underwent pre- and post-rTMS magnetic resonance imaging (MRI) scans while completing a cognitive-affective distress task with negative auditory feedback. rTMS coil placement over the right postcentral gyrus was guided with neuronavigation, and TBFC analysis of the MRI data was performed using the bilateral auditory cortex as a seed region-of-interest. Results: There was an false discovery rate (FDR)-corrected significant group-by-session-by-condition interaction in a right putamen/posterior insula cluster: in the distress condition, the 1 Hz rTMS group had significantly weaker (i.e., smaller absolute value) negative TBFC following rTMS (p = 0.005), while the 10 Hz group had no significant effect. Conclusion: This preliminary, proof-of-concept study suggests that rTMS can modulate TBFC in distal brain regions implicated in the neural response to cognitive-affective negative feedback. Future research should investigate whether rTMS can both modulate insula-associated TBFC and improve cognitive-affective task performance or mood outcomes, potentially by increasing the number of rTMS sessions or using different rTMS pulse sequences. Impact Statement Clinical application of repetitive transcranial magnetic stimulation (rTMS) may exert a therapeutic effect by modulating the strength of functional connectivity between superficial cortical areas and deeper brain regions. These effects on functional connectivity are typically measured while participants are at rest. This proof-of-concept study suggests that rTMS can have a measurable effect on task-based functional connectivity as well. In the future, this could be an important means of understanding how rTMS exerts effects on cognitive-affective task performance and mood.