Brain Functional Connectivity Research Articles

Elevated vascular endothelial growth factor a is associated with disruption of default network connectivity in older adults.

Vascular Endothelial Growth Factor A (VEGF-A) is an angiogenic signaling protein involved in the maintenance of the cerebral vasculature. No prior study has explored whether plasma VEGF-A levels may be associated with brain functional connectivity changes, such as disruption of the default mode network (DMN), which often precedes the development of cognitive changes in aging. Seventy-six independently living older adults (mean age = 70.3 years; SD = 7.5; 31.6% male) free of dementia or clinical stroke underwent venipuncture and brain MRI. Plasma was assayed for VEGF-A. Using resting state functional MRI, region of interest (ROI) to ROI connectivity and graph theory analysis were conducted to determine average connectivity and global efficiency between each of the following ROIs comprising the DMN: medial prefrontal cortex, lateral parietal cortex and precuneus cortex. Multiple linear regression analysis revealed a significant negative association between VEGF-A levels and DMN connectivity (B = - 0.14, 95% CI (-0.26, - 0.01), p =.038), accounting for age, sex, education, and vascular risk factors. Graph theory analysis similarly revealed that VEGF-A levels are associated with global efficiency of the entire network (B = - 0.18, p =.004). These findings suggest that VEGF-A may be elevated early in the progression of neurocognitive disorders. Whether higher levels of VEGF-A contribute to the pathogenesis of neurocognitive disorders or play a protective role in preserving cognitive function warrants further investigation. Clinical Trial Number: N/A; None.

Ketamine effects on resting state functional brain connectivity in major depressive disorder patients: a hypothesis-driven analysis based on a network model of depression

IntroductionKetamine demonstrates robust and rapidly occurring antidepressant effects in patients with difficult-to-treat major depressive disorder. Ketamine’s antidepressant effects and its impact on functional networks in non-resistant forms of major depressive disorder are expected to provide valuable insight into ketamine’s mechanism of action related to depression.MethodsThis study employs an existing network model of major depressive disorder to investigate the effects of ketamine on resting state connectivity in a therapy-non-resistant major depressive disorder population. In a randomized, double-blind, placebo-controlled, cross-over study, 0.5 mg/kg racemic ketamine or 0.9%NaCl was administered intravenously in 16 MDD patients. We applied resting-state functional magnetic resonance imaging (rs-fMRI) to explore changes in functional brain connectivity directly at 50, 80 and 165 min (acute) and 24 h (delayed) following ketamine administration. A clinician-rated 10-item scale (MADRS) was administered at 165 min and 24 h after ketamine administration. Connections-of-interest (COIs) were based on the previously published corticolimbic-insular-striatalpallidal-thalamic (CLIPST) circuitry model of major depressive disorder.ResultsCompared with placebo, ketamine significantly (p < 0.0014) reduced the mean (SD) MADRS total score from 21.2 (5.9) pre-dose to 10.3 (4.6) 24 h post-dose. At both acute (p < 0.0172) and delayed (p < 0.0488) time points, significant rs-fMRI connectivity changes occurred only in MDD-related COIs as proposed by the CLIPST model. No changes in functional connectivity were found in non-CLIPST connections.DiscussionThis study demonstrates that ketamine specifically affects depression-related circuitry. Analyzing functional connectivity based on a neurocircuitry model of a specific CNS disease and drug action may be an effective approach that could result in a more targeted analysis in future pharmaco-fMRI studies in CNS drug development.

Crochet increases attention through a requiring motor skill learning

In this study, we compared the effects promoted by a brief single session of crochet in a group of skilled knitters (CRO) and a control group (CRT) on the Attentional Network Test (ANT) and the whole brain Functional Connectivity (FC) revealed by Magnetoencephalography (MEG). Data revealed that crochet determined a significant effect (before, T0, vs after, T1, the crochet session) on reaction times (for all cue and stimulus types), improving alertness and orienting networks (but not executive control) only in the CRO group. Data of FC are coherent with the behavioural ones. We observed that the Betweenness Centrality maximum (BCmax) index in the beta band significantly increased, and global FC in the alpha band significantly increased at T1 for the CRO group but not for the CTR group. Increased global BCmax in the beta band after the crochet activity correlated with better performance (reduced reaction times), suggesting that the brain has become more efficiently integrated, thus increasing the information exchange between different brain areas. Decreased global FC in the alpha band may reflect a transition from a quiet, global rest to a condition of increased alertness and readiness to stimuli. Finally, we discuss the hypothesis that these results could be the reinforcement of connections between motor and attentional networks promoted by learning the complex motor skills of crochet.

Intrinsic brain functional connectivity mediates the relationship between psychological resilience and cognitive decline in ageing.

Ageing individuals often experience cognitive decline and intrinsic functional connectivity (FC) changes. Psychological resilience, a personality trait that reflects the capacity to adapt and cope with age-related challenges, plays a key role in mitigating cognitive decline. In this study involving 101 older adults, we investigated how psychological resilience influences cognitive decline measured by processing speed. Particularly, we obtained resting-state functional magnetic resonance imaging (fMRI) to assess how intrinsic FC, represented by degree centrality, modulates the relationship between resilience and processing speed. Our results indicated while psychological resilience positively predicted processing speed, this relationship was mainly driven by education. Additionally, the degree centrality of both thalamus and caudate negatively correlated with processing speed and resilience. Notably, the degree centrality of both thalamus and caudate significantly mediated the relationship between resilience and processing speed. These findings suggest that psychological resilience could protect against age-related cognitive decline via its influence on FC in the thalamus and caudate, highlighting these areas as potential intervention targets for reducing cognitive decline in ageing people.

Functional connectivity in burnout syndrome: a resting-state EEG study

Chronic occupational stress is associated with a pronounced decline in emotional and cognitive functioning. Studies on neural mechanisms indicate significant changes in brain activity and changed patterns of event-related potentials in burnout subjects. This study presents an analysis of brain functional connectivity in a resting state, thus providing a deeper understanding of the mechanisms accompanying burnout syndrome. The sample consists of 49 burnout employees and 49 controls, matched by age, gender and occupation (Mage = 36.15, SD = 8.10; 59 women, 39 men). Continuous dense-array EEG data were collected from a 256-channel EEG system. The difference in functional connectivity between burnout and control subjects was tested in the eyes-closed (EC) and eyes-open (EO) conditions using the resting-state paradigm. The results indicate significant differences in brain activity between the burnout and the control groups. The resting-state network of the burnout group is characterized by decreased functional connectivity in frontal and midline areas in the alpha3 sub-band (11–13 Hz) in an eyes-open condition. The most significant effect of decreased connectivity was observed in the right frontal brain area. For the first time, these analyses point to distinctive aspects of functional connectivity within the alpha3 sub-band in burnout syndrome. These findings provide insights into the neurobiological underpinnings of burnout syndrome and its associations with changed resting-state networks. The data on neural characteristics in burnout subjects may help to understand the mechanisms of decline in cognitive function and emotion regulation and to search for adequate methods of treatment.

Functional near-infrared spectroscopy for the assessment and treatment of patients with disorders of consciousness

BackgroundAdvances in neuroimaging have significantly enhanced our understanding of brain function, providing critical insights into the diagnosis and management of disorders of consciousness (DoC). Functional near-infrared spectroscopy (fNIRS), with its real-time, portable, and noninvasive imaging capabilities, has emerged as a promising tool for evaluating functional brain activity and nonrecovery potential in DoC patients. This review explores the current applications of fNIRS in DoC research, identifies its limitations, and proposes future directions to optimize its clinical utility.AimThis review examines the clinical application of fNIRS in monitoring DoC. Specifically, it investigates the potential value of combining fNIRS with brain-computer interfaces (BCIs) and closed-loop neuromodulation systems for patients with DoC, aiming to elucidate mechanisms that promote neurological recovery.MethodsA systematic analysis was conducted on 155 studies published between January 1993 and October 2024, retrieved from the Web of Science Core Collection database.ResultsAnalysis of 21 eligible studies on neurological diseases involving 262 DoC patients revealed significant findings. The prefrontal cortex was the most frequently targeted brain region. fNIRS has proven crucial in assessing brain functional connectivity and activation, facilitating the diagnosis of DoC. Furthermore, fNIRS plays a pivotal role in diagnosis and treatment through its application in neuromodulation techniques such as deep brain stimulation (DBS) and spinal cord stimulation (SCS).ConclusionAs a noninvasive, portable, and real-time neuroimaging tool, fNIRS holds significant promise for advancing the assessment and treatment of DoC. Despite limitations such as low spatial resolution and the need for standardized protocols, fNIRS has demonstrated its utility in evaluating residual brain activity, detecting covert consciousness, and monitoring therapeutic interventions. In addition to assessing consciousness levels, fNIRS offers unique advantages in tracking hemodynamic changes associated with neuroregulatory treatments, including DBS and SCS. By providing real-time feedback on cortical activation, fNIRS facilitates optimizing therapeutic strategies and supports individualized treatment planning. Continued research addressing its technical and methodological challenges will further establish fNIRS as an indispensable tool in the diagnosis, prognosis, and treatment monitoring of DoC patients.

Transitioning from perceived stress to mental health: The mediating role of self-control in a longitudinal investigation with MRI scans.

The neural mechanisms and long-term effects of perceived stress (PS) and self-control (SC) on mental health (MH) are not fully understood. This study seeks to investigate the influence of PS and SC on MH and to identify their neural correlates using fMRI. A total of 817 college students participated in behavioral assessments, including the Perceived Stress Scale (PSS), Self-Control Scale (SCS), and Mental Health Continuum Short Form (MHC-SF). Among them, 371 underwent fMRI scans to calculate zfALFF and whole-brain functional connectivity. Additionally, their behavioral measures were reassessed two years later. Longitudinal behavioral data revealed significant fixed effects of perceived stress and self-control on mental health. Perceived stress significantly predicted decreased mental health at Time 2, and self-control acted as a mediator in such relationship. The results of the behavioral and brain model analyses found that zfALFF in the right temporal region negatively predicted self-control. Functional connectivity between the right temporal region and the right precentral gyrus was also found to negatively predict self-control. This study highlights the mediating role of self-control in the relationship between perceived stress and mental health. It also identifies specific brain regions and functional connectivity associated with self-control, providing new neurobiological evidence for mental health interventions.

Altered brain activity and functional connectivity in psychogenic erectile dysfunction: Combining findings from LOOCV-SVM-RFE and rs-fMRI.

Psychogenic erectile dysfunction (pED) is often accompanied by abnormal brain activities. This study aimed to develop an automaticclassifier to distinguish pED from healthy controls (HCs) by identified brain-basedcharacteristics. Resting-state functional magnetic resonance imaging data were acquired from 45 pED patients and 43 HCs. Regional homogeneity (ReHo) and functional connectivity (FC) values were calculated and compared between groups. Moreover, based on altered ReHo and FC values, support vector machine (SVM) classifier, incorporating recursive feature elimination (RFE), an SVM-RFE diagnostic model was established using leave-one-out cross-validation. Patients demonstrated reduced ReHo values in the left middle temporal gyrus (had decreased FC values with the left medial superior frontal gyrus and cuneus), orbital part of inferior frontal gyrus (had decreased FC values within the same region), triangular part of inferior frontal gyrus, anterior cingulate gyrus (had decreased FC values with the left inferior temporal gyrus, anterior cingulate gyrus, cuneus and right supplementary motor area) and middle frontal gyrus. The right calcarine fissure displayed increased ReHo values. The diagnostic model demonstrated excellent performance, achieving an accuracy rate of 90.80%. This study identified altered regional activity and FC in specific brain regions of pED patients, which might be related to the development of pED. The application of machine learning confirmed the distinctive characteristics of these functional changes in the brain. The high accuracy of our diagnostic model suggested a promising direction for developing objective diagnostic tools for psychological disorders.

Abstract 26: First-in-human Phase 1/2a Study of Intracerebral Transplantation using Embryonic-derived Neural Stem Cells (NR1) for Chronic Ischemic Stroke (NCT04631406): 12 Months Outcomes

Introduction: Except for vagal nerve stimulation, no treatment exists to restore function in chronic stroke patients. Several prior intracerebral stem cell trials were promising, but are not being further developed. Objective: NR1 is a human embryonic derived neural stem cell that improved motor-sensory function in rodent stroke models, and was expanded to produce GMP cryopreserved cell lots. The safety&efficacy of NR1 intracerebral transplantation in chronic stroke patients was assessed over 12 months. Methods: Inclusion Criteria: 18-75 yo; 6-60 mos post-ischemic subcortical MCA stroke; mRS 3-4. Subjects were transplanted with 2.5M, 5M, 10M or 20M. Primary Outcomes: Adverse events 0-12 mos; Change in total Fugl-Meyer motor score (FMMS, max 100) compared to baseline at 12 months (≥10 points improvement considered “clinically meaningful”). Other outcomes: UE FMMS, LE FMMS, Gait Speed test, Barthel Index (BI), NIHSS, MR FLAIR, Resting State fMRI and [18F]FDG PET. Results: 18 patients were transplanted. Adverse events included headache, worsened baseline expressive aphasia and asymptomatic chronic subdural hygroma, all resolving spontaneously. All 17 pts with f/u ≥3 mos demonstrated improved total FMMS and 11 of these 17 subjects showed clinically meaningful recovery in total FMMS. At 12 mos subjects increased 12.1 (+/- 1.8) points for total FMMS (p=0.00002), 7.4 (+/-1.6) points for UE FMMS (p=0.00057), 4.7 (+/-0.5) points for LE FMMS (p =0.0000009), 7.7 (+/-2.5) points for BI, while NIHSS improved by 1.77 (+/-0.47) and gait speed improved substantially. 14/18 pts demonstrated new transient FLAIR signal in premotor cortex at d7, that resolved by 2 mos, which was highly correlated with sustained neurologic recovery. Resting state fMRI showed improved functional brain connectivity in sensorimotor network, both ipsilesionally&contralesionally. FDG PET showed increased activity in the ipsilesional motor cortex&contralesional cerebellum. Conclusions: Intraparenchymal transplantation of NR1 cells in chronic stroke patients appears safe and well tolerated. Results suggest improved motor function starting at 1 mos and increasing to clinically meaningful recovery in most patients at 12 mos post-implant. UE FMMS improvement surpassed vagal nerve stimulation outcomes.

Functional Brain Connectivity Predictors of Prospective Substance Use Initiation in Adolescence

Functional Brain Connectivity Predictors of Prospective Substance Use Initiation in Adolescence

Time-Frequency functional connectivity alterations in Alzheimer's disease and frontotemporal dementia: An EEG analysis using machine learning.

Alzheimer's disease (AD) and frontotemporal dementia (FTD) are prevalent neurodegenerative diseases characterized by altered brain functional connectivity (FC), affecting over 100 million people worldwide. This study aims to identify distinct FC patterns as potential biomarkers for differential diagnosis. Resting-state EEG data from 36 AD patients, 23 FTD patients, and 29 healthy controls were analyzed using time-frequency and bandpass filtering FC metrics. These metrics were estimated through Pearson's correlations, mutual information, and phase lag index, and served as input features in a support vector machine (SVM) with Leave-One-Out Cross-Validation for group classification. Both AD and FTD exhibited significantly decreased FC in the theta band within the frontal lobe and increased FC in the beta band in the posterior regions. Additionally, a decreased FC in central regions at theta band was observed uniquely in AD, but not in FTD. SVM classification accuracies reached 95% for AD and 86% for FTD. High classification accuracies underscore the potential of these FC alterations as reliable biomarkers for AD and FTD. This is the first study to integrate time-frequency and bandpass filtering FC metrics to reveal brain network alterations in AD and FTD, providing new insights for diagnostics and neurodegenerative pathologies.

A Statistical Characterization of Dynamic Brain Functional Connectivity.

This study examined the statistical underpinnings of dynamic functional connectivity in mental disorders, using resting-state fMRI signals. Notably, there has been an absence of research demonstrating the non-stationarity of the empirical probability distribution of functional connectivity. This gap has prompted debate on the existence of dynamic functional connectivity, leading skeptics to question its relevance and the reliability of research findings. Our aim was to fill this gap by conducting a comprehensive empirical distribution analysis of functional connectivity, using Pearson's correlation as a measure. We conducted our analysis on a set of preprocessed resting-state fMRI samples obtained from 186 subjects selected from the UCLA Consortium for Neuropsychiatric Phenomics dataset. Departing from conventional methods that aggregated signals over voxels within a region of interest, our approach leveraged individual voxel signals. Specifically, our approach offered a precise characterization of the empirical probability distribution of resting-state fMRI signals by evaluating the temporal variations and non-stationarity in dynamic functional connectivity, as measured by Pearson's correlation. Our study investigated functional connectivity patterns across 49 regions of interest, comparing healthy control subjects with patients diagnosed with ADHD, bipolar disorder, and schizophrenia. Our analysis revealed that (1) the empirical distribution of the correlation coefficient exhibited non-stationarity, (2) the beta distribution was an accurate approximation of the exact correlation coefficient distribution, and (3) the empirical distribution of means derived from the fitted beta distributions, unraveled distinctive dynamic functional connectivity patterns with potential as biomarkers associated with different mental disorders. A key contribution of our study was the presentation of the first comprehensive empirical distribution analysis of dynamic functional connectivity, thus providing compelling evidence for its existence. Overall, our study presented an innovative statistical approach that advances our understanding of the dynamic nature of functional connectivity patterns derived from resting-state fMRI. Our examination of the empirical distribution of dynamic functional connectivity provided solid evidence supporting its existence. The distinctive dynamic functional connectivity patterns we identified across various mental disorders hold promise as potential biomarkers for further development.

Altered brain functional network connectivity and topology in type 2 diabetes mellitus

IntroductionType 2 diabetes mellitus (T2DM) accelerates brain aging and disrupts brain functional network connectivity, though the specific mechanisms remain unclear. This study aimed to investigate T2DM-driven alterations in brain functional network connectivity and topology.MethodsEighty-five T2DM patients and 67 healthy controls (HCs) were included. All participants underwent clinical, neuropsychological, and laboratory tests, followed by MRI examinations, including resting-state functional magnetic resonance imaging (rs-fMRI) and three-dimensional high-resolution T1-weighted imaging (3D-T1WI) on a 3.0 T MRI scanner. Post-image preprocessing, brain functional networks were constructed using the Dosenbach atlas and analyzed with the DPABI-NET toolkit through graph theory.ResultsIn T2DM patients, functional connectivity within and between the default mode network (DMN), frontal parietal network (FPN), subcortical network (SCN), ventral attention network (VAN), somatosensory network (SMN), and visual network (VN) was significantly reduced compared to HCs. Conversely, two functional connections within the VN and between the DMN and SMN were significantly increased. Global network topology analysis showed an increased shortest path length and decreased clustering coefficient, global efficiency, and local efficiency in the T2DM group. MoCA scores were negatively correlated with the shortest path length and positively correlated with global and local efficiency in the T2DM group. Node network topology analysis indicated reduced clustering coefficient, degree centrality, eigenvector centrality, and nodal efficiency in multiple nodes in the T2DM group. MoCA scores positively correlated with clustering coefficient and nodal efficiency in the bilateral precentral gyrus in the T2DM group.DiscussionThis study demonstrated significant abnormalities in connectivity and topology of large-scale brain functional networks in T2DM patients. These findings suggest that brain functional network connectivity and topology could serve as imaging biomarkers, providing insights into the underlying neuropathological processes associated with T2DM-related cognitive impairment.

Functional connectivity and metabolic brain alterations in sleepwalkers.

Disorders of arousal (DoA) are characterized by an intermediate state between wakefulness and deep sleep, leading to incomplete awakenings from NREM sleep. Multimodal studies have shown subtle neurophysiologic alterations even during wakefulness in DoA. The aim of this study was to explore the brain functional connectivity in DoA and the metabolic profile of the anterior and posterior cingulate cortex, given its pivotal role in cognitive and emotional processing. Fifteen consecutive patients with DoA (9 males, mean age 26.3 ± 7.7) and 15 age- and sex-matched healthy controls (8 males, mean age 25.8 ± 3.6) were enrolled. All participants underwent a protocol including sleep and psychological evaluation scales and multimodal brain MRI with resting-state functional MRI and 1H-MR spectroscopy. The independent component analysis disclosed an altered resting-state functional connectivity (FC) in the patients' sensory motor network, with a higher connectivity strength in opercular cortex, precuneus, occipital pole, and lingual gyrus. The seed-based analysis revealed a decreased FC between posterior cingulate cortex (PCC) and several cerebral areas. Finally, spectroscopic imaging revealed a reduced content of glutamine in the PCC (p < 0.001). The increased connectivity in the sensory-motor network of DoA patients could constitute a "facilitatory medium" enhancing motor circuit activation, while the connectivity and metabolic alterations of PCC might represent a trait functional feature, contributing to a dysfunctional arousal process and the difficulty to reach a complete awareness during DoA episodes. In addition, these alterations at rest might be related to daytime impairment reported by patients, requiring new strategies for DoA management.

Electrophysiological biomarkers based on CISANET characterize illness severity and suicidal ideation among patients with major depressive disorder.

Major depressive disorder (MDD) is a significant neurological disorder that imposes a substantial burden on society, characterized by its high recurrence rate and associated suicide risk. Clinical diagnosis, which relies on interviews with psychiatrists and questionnaires used as auxiliary diagnostic tools, lacks precision and objectivity in diagnosing MDD. To address these challenges, this study proposes an assessment method based on EEG. It involves calculating the phase lag index (PLI) in alpha and gamma bands to construct functional brain connectivity. This method aims to find biomarkers to assess the severity of MDD and suicidal ideation. The convolutional inception with shuffled attention network (CISANET) was introduced for this purpose. The study included 61 patients with MDD, who were classified into mild, moderate, and severe levels based on depression scales, and the presence of suicidal ideation was evaluated. Two paradigms were designed for the study, with EEG analysis focusing on 32 selected electrodes to extract alpha and gamma bands. In the gamma band, the classification accuracy reached 77.37% in the visual paradigm and 80.12% in the auditory paradigm. The average accuracy in classifying suicidal ideation was 93.60%. The findings suggest that gamma bands can be used as potential biomarkers differentiating illness severity and identifying suicidal ideation of MDD, and that objective assessment methods can effectively assess MDD The objective assessment method can effectively assess the severity of MDD and identify suicidal ideation of MDD patients, which provides a valuable theoretical basis for understanding the biological characteristics of MDD.

Neural Correlates of Social Touch Processing: An fMRI Study on Brain Functional Connectivity.

The significance of tactile stimulation in human social development and personal interaction is well documented; however, the underlying cerebral processes remain under-researched. This study employed functional magnetic resonance imaging (fMRI) to investigate the neural correlates of social touch processing, with a particular focus on the functional connectivity associated with the aftereffects of touch. A total of 27 experimental subjects were recruited for the study, all of whom underwent a 5-minute calf and foot massage prior to undergoing resting-state fMRI. Additionally, 11 healthy controls participated solely in the resting-state fMRI recording. A functional connectivity network analysis was conducted to examine the alterations in connections between different brain regions following massage. The findings indicated the involvement of discrete neural networks in the processing of social touch, with notable discrepancies in functional connectivity observed between the experimental and control groups. The study revealed that the control group exhibited a higher degree of connectivity within a subnetwork comprising 25 connections and 23 nodes than the experimental group following the massage intervention. The experimental group showed hypoactivation in this subnetwork following the massage. The left anterior pulvinar thalamus and the right pregenual anterior cingulate cortex, which serve as the key hubs within this subnetwork, exhibited higher clustering and increased node strength in the control group. Relatively small and unequal sample sizes are the limitations of the study that may affect the generalizability of the results. These findings elucidate the neural underpinnings of tactile experiences and their potential impact on behavior and emotional state. Gaining insight into these mechanisms could inform therapeutic approaches that utilize touch to mitigate stress and enhance mental health. From a practical standpoint, our results have significant implications for the development of sensory stimulation strategies for patients with prolonged disorders of consciousness, sensory loss, autism spectrum disorders, or limited access to tactile interaction in their upper extremities.

Potential associations between altered brain function, cognitive deficits and gene expressing profiles in bipolar disorder across three clinical stages.

We aimed to determine the relationship between altered brain imaging characteristics, cognitive function and profiles of gene expression of bipolar disorder (BD). Functional magnetic resonance imaging (fMRI) was presented in three groups of BD participants (depressed, manic and euthymic) and healthy controls. Regional Homogeneity (ReHo) and region of interest based functional analysis combining with neuroimaging-transcription association analysis were utilized to investigate abnormalities and their correlation with clinical symptoms. Our data showed that all three groups of BD patients exhibited significantly altered ReHo values whilst the bilateral precuneus/posterior cingulate cortex (PCC) and lateral occipital cortex exhibited significant increase in BD. Functional connectivity (FC) revealed distinct characteristics of the precuneus/PCC-based default mode network. ReHo values in the Precuneus/middle cingulate cortex displayed significantly negative correlations with cognition and YMRS scores. Gene enrichment analysis also revealed that ReHo values were spatially correlated with pathways including chromatin organization and innate immune response. Altered ReHo values in specific brain regions may be associated with different clinical stages and increased FC in brain may potentially function as BD imaging biomarkers. The heterogeneity of gene expression was associated with altered brain imaging properties in BD, contributing to distinguishing different stages of BD from healthy individuals.

Static and dynamic brain functional connectivity patterns in patients with unilateral moderate-to-severe asymptomatic carotid stenosis.

Asymptomatic carotid stenosis (ACS) is an independent risk factor for ischemic stroke and vascular cognitive impairment, affecting cognitive function across multiple domains. This study aimed to explore differences in static and dynamic intrinsic functional connectivity and temporal dynamics between patients with ACS and those without carotid stenosis. We recruited 30 patients with unilateral moderate-to-severe (stenosis ≥ 50%) ACS and 30 demographically-matched healthy controls. All participants underwent neuropsychological testing and 3.0T brain MRI scans. Resting-state functional MRI (rs-fMRI) was used to calculate both static and dynamic functional connectivity. Dynamic independent component analysis (dICA) was employed to extract independent circuits/networks and to detect time-frequency modulation at the circuit level. Further imaging-behavior associations identified static and dynamic functional connectivity patterns that reflect cognitive decline. ACS patients showed altered functional connectivity in multiple brain regions and networks compared to controls. Increased connectivity was observed in the inferior parietal lobule, frontal lobe, and temporal lobe. dICA further revealed changes in the temporal frequency of connectivity in the salience network. Significant differences in the temporal variability of connectivity were found in the fronto-parietal network, dorsal attention network, sensory-motor network, language network, and visual network. The temporal parameters of these brain networks were also related to overall cognition and memory. These results suggest that ACS involves not only changes in the static large-scale brain network connectivity but also dynamic temporal variations, which parallel overall cognition and memory recall.

Altered brain functional connectivity in patients with tension-type headache.

To evaluate whether patients with tension-type headache (TTH) exhibit abnormal brain functional connectivity compared to healthy controls. TTH is one of the most prevalent headache disorders throughout the world. The present study delves into brain functional connectivity in patients with TTH to enhance the understanding of its underlying pathophysiology. A cross-sectional study was conducted, enrolling patients with TTH diagnosed in line with the International Classification of Headache Disorders, 3rd edition beta criteria and a cohort of healthy controls (HCs). We used four metrics-global brain functional connectivity, functional connectivity, Granger causality analysis, and dynamic functional connectivity-to evaluate alterations of functional connectivity patterns in patients with TTH from both static and dynamic perspectives. Furthermore, correlational analyses were performed to explore the relationships between abnormal brain activities and clinical characteristics. A total of 33 patients with TTH (mean age = 42.3; 13 males/20 females) and 30 HCs (mean age = 37.1; 13 males/17 females) were included in the current study. Compared to HCs, patients with TTH showed altered global brain functional connectivity in the right dorsolateral superior frontal gyrus (SFGdor, t = 4.60). Abnormal functional connectivity was also detected between the right SFGdor and the right superior temporal gyrus (t = 4.56). Furthermore, the right SFGdor exhibited altered information flow with several brain regions, including the left precuneus (t = 5.16), right middle temporal gyrus (MTG, t = 4.72/-4.41), right inferior temporal gyrus (t = 4.64), right caudate nucleus (t = 4.09), and right thalamus (THA, t = -4.04). In terms of dynamic functional connectivity, disconnection was observed between the right SFGdor and the right MTG (t = -3.10), right Rolandic operculum (ROL, t = 3.60), left opercular inferior frontal gyrus (t = -3.48), and left medial superior frontal gyrus (t = -3.00). In addition, the correlation analyses revealed that activities in the MTG (r = 0.48), THA (r = -0.38), and ROL (r = 0.36) were significantly correlated with disease duration, while THA activity was associated with Visual Analogue Scale scores (r = 0.50). This study revealed alterations in both static and dynamic brain functional connectivity in patients with TTH within regions implicated in sensory perception, emotional processing, cognition, and pain regulation. These results may promote the understanding of the neural networks involved in TTH and potentially inform future therapeutic approaches for the condition.

Altered amplitude of low-frequency fluctuation and functional connectivity in patients with acute unilateral vestibulopathy: a resting-state fMRI study.

To investigate changes of brain functional activity in patients with acute unilateral vestibulopathy (AUVP) using functional magnetic resonance imaging (fMRI). We studied 32 AUVP patients and 30 healthy controls (HC) who received resting-state fMRI scanning. Methods of voxel-based amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity (FC) were adopted to compare the difference in brain function between the two groups. In addition, we evaluated the associations between abnormal neuroimaging results and clinical data in AUVP patients. Compared with HC, patients with AUVP showed lower ALFF in brain regions of bilateral insular, right precentral gyrus, left inferior frontal gyrus and right middle frontal gyrus, as well as higher ALFF in left cerebellar anterior lobe. Using these abnormal brain areas as seeds, we observed decreased FC between left insular and left precuneus in AUVP patients. Furthermore, AUVP patients showed increased FC between left insular and left supplementary motor area. Results of correlation analysis indicated that ALFF value (z-value) in left insular was negatively correlated with the canal paresis value (p = 0.005, r = -0.483), and the FC (z-value) between left insular and left precuneus was negatively correlated with dizziness handicap inventory score (p = 0.012, r = -0.438) in patients with AUVP. Patients with AUVP during acute period showed altered functional activity and connectivity in brain regions mainly involved in motor control and vestibular information processing. These changes in brain functional activity and connectivity were potentially attributed to decreased vestibular input resulting from unilateral peripheral vestibular impairment.