Voxel-mirrored Homotopic Connectivity Values Research Articles

Higher inter-hemispheric homotopic connectivity in lifelong premature ejaculation patients: a pilot resting-state fMRI study.

Lifelong premature ejaculation (PE) is one common male sexual dysfunction and is implicated in widespread structural and functional abnormalities of bilateral hemispheres. However, whether the inter-hemisphere functional connectivity (FC) of lifelong PE patients was altered still remain unclear. Thirty-four lifelong PE patients and 30 healthy controls (HCs) were enrolled in this study and all underwent T1-weighted and resting-state functional MRI (fMRI) scan. The voxel-mirrored homotopic connectivity (VMHC) measure and independent sample t-test were applied to examine the alterations of VMHC values in the patients relative to HCs with the significant threshold at P<0.05, false discovery rates corrected. Correlation analysis was adopted to calculate the relationships between the imaging results and clinical characteristics of patients (P<0.05, Bonferroni corrected). Receiver operating characteristic (ROC) curve analysis was performed to investigate the possible biomarkers for distinguishing the patients from the HCs using the VMHC values of inter-group differences. The results revealed that compared with HCs, lifelong PE patients had higher VMHC values in the precentral gyrus (PG), primary somatosensory cortex (S1), supplementary motor area (SMA), precuneus, middle temporal cortex (MTC), superior temporal pole (STP), thalamus, caudate and middle cingulate cortex (MCC). Correlation analysis showed that the mean VMHC values in the S1 negatively correlated with intravaginal ejaculation latency time (IELT) in the patient group. Furthermore, the caudate revealed the well classification power from the ROC analysis. The present study showed the abnormal inter-hemisphere interaction and integration of information involved in ejaculation inhibitory control, sensorimotor mediation and self-reference processing including the thalamus, caudate, MCC, widespread parietal cortex and temporal cortex in lifelong PE patients compared with HCs. Correlation analysis and ROC analysis revealed the importance of S1 and caudate in lifelong PE. Notably, the ROC result of caudate might show the core roles of caudate played in the pathophysiology of lifelong PE.

Interhemispheric resting-state functional connectivity abnormalities in type 2 diabetes patients.

There has been a considerable focus on the changes of functional connections between brain regions in patients with type 2 diabetes mellitus (T2DM) by previous resting-state functional magnetic resonance imaging (rs-fMRI) studies. However, little is known about the function of brain information integration between the two hemispheres of the brain. This study explores differences in interhemispheric coordination between T2DM patients and normal control (NC) subjects using the voxel-mirrored homotopic connectivity (VMHC) method. We also assess whether differences in VMHC were relevant to cognitive dysfunction in T2DM patients. Sixty-nine T2DM patients and 69 NC subjects were enrolled (matched for age, sex and education level). All participants underwent cognitive assessments. VMHC between brain regions was obtained by rs-fMRI analysis. Partial correlation analysis (after controlling for age, sex and education level) was used to explore the correlation between VMHC value and neuropsychological tests. Compared with NC subjects, T2DM patients exhibited significantly lower VMHC in the medial orbitofrontal gyrus cortex (mOFC), anterior cingulate gyrus, inferior parietal lobe, superior and middle temporal gyrus (MTG), middle occipital gyrus, and superior occipital gyrus. Moreover, after applying Bonferroni correction, the Montreal Cognitive Assessment (MoCA) score and VMHC value for the MTG were significantly positively correlated in T2DM patients. In contrast, T2DM patients exhibited higher VMHC in the cerebellum posterior lobe and tonsil and inferior temporal gyrus than the NCs. Our study indicates that functional coordination between homotopic brain regions is generally impaired in T2DM patients. In brain regions with decreased VMHC in the default mode network (DMN), MTG impairment could serve as a critical node for T2DM-related cognitive dysfunction. Furthermore, the increased VMHC observed in the cerebellum and inferior temporal gyrus might indicate a functional coordination mechanism.

Abnormal interhemispheric functional connectivity in patients with strabismic amblyopia: a resting-state fMRI study using voxel-mirrored homotopic connectivity

BackgroundPrevious studies have demonstrated that strabismus amblyopia can result in markedly brain function alterations. However, the differences in spontaneous brain activities of strabismus amblyopia (SA) patients still remain unclear. Therefore, the current study intended to employthe voxel-mirrored homotopic connectivity (VMHC) method to investigate the intrinsic brain activity changes in SA patients.PurposeTo investigate the changes in cerebral hemispheric functional connections in patients with SA and their relationship with clinical manifestations using the VMHC method.Material and methodsIn the present study, a total of 17 patients with SA (eight males and nine females) and 17 age- and weight-matched healthy control (HC) groups were enrolled. Based on the VMHC method, all subjects were examined by functional magnetic resonance imaging. The functional interaction between cerebral hemispheres was directly evaluated. The Pearson’s correlation test was used to analyze the clinical features of patients with SA. In addition, their mean VMHC signal values and the receiver operating characteristic curve were used to distinguish patients with SA and HC groups.ResultsCompared with HC group, patients with SA had higher VMHC values in bilateral cingulum ant, caudate, hippocampus, and cerebellum crus 1. Moreover, the VMHC values of some regions were positively correlated with some clinical manifestations. In addition, receiver operating characteristic curves presented higher diagnostic value in these areas.ConclusionSA subjects showed abnormal brain interhemispheric functional connectivity in visual pathways, which might give some instructive information for understanding the neurological mechanisms of SA patients.

Interhemispheric Functional Connectivity Alterations in Diabetic Optic Neuropathy: A Resting-State Functional Magnetic Resonance Imaging Study.

PurposePrevious research suggests that diabetic optic neuropathy (DON) can cause marked anatomical and functional variations in the brain, but to date altered functional synchronization between two functional hemispheres remains uncharacterized in DON patients. Voxel mirrored homotopic connectivity (VMHC) is a voxel-based method to evaluate the synchronism between two mirrored hemispheric by determining the functional connectivity between each voxel in one hemisphere and its counterpart. In this study, we aim to assess abnormal changes in interhemispheric functional connectivity in DON patients via the VMHC method.MethodsThe study included 28 adult DON patients (12 male, 16 female) and 28 healthy controls (12 male, 16 female) who were closely matched for sex and age. Participants were examined using resting-state functional magnetic resonance imaging. The VMHC method was applied to investigate the abnormal state in bilateral hemispheres in DON patients and the same regions in healthy controls, as well as the receiver operating characteristic (ROC) curves were used to evaluate characteristics. Associations between altered VMHC values in distinct cerebral regions and clinical features were assessed via correlational analysis.ResultsMarkedly lower VMHC values were evident in the right temporal inferior, the left temporal inferior, the right mid-cingulum, the left mid-cingulum, the right supplementary motor region, and the left supplementary motor region in DON patients compared with healthy controls. ROC curve analysis suggested that the application of VMHC is reliable for the diagnosis of DON.ConclusionAnomalous interhemispheric functional connectivity in specific brain areas caused by DON may indicate neuropathologic mechanisms of vision loss and blurry vision in patients with DON.

Increased Resting-State Interhemispheric Functional Connectivity of Posterior Superior Temporal Gyrus and Posterior Cingulate Cortex in Congenital Amusia.

Interhemispheric connectivity of the two cerebral hemispheres is crucial for a broad repertoire of cognitive functions including music and language. Congenital amusia has been reported as a neurodevelopment disorder characterized by impaired music perception and production. However, little is known about the characteristics of the interhemispheric functional connectivity (FC) in amusia. In the present study, we used a newly developed voxel-mirrored homotopic connectivity (VMHC) method to investigate the interhemispheric FC of the whole brain in amusia at resting-state. Thirty amusics and 29 matched participants underwent a resting-state functional magnetic resonance imaging (fMRI) scanning. An automated VMHC approach was used to analyze the fMRI data. Compared to the control group, amusics showed increased VMHC within the posterior part of the default mode network (DMN) mainly in the posterior superior temporal gyrus (pSTG) and posterior cingulate cortex (PCC). Correlation analyses revealed negative correlations between the VMHC value in pSTG/PCC and the music perception ability among amusics. Further ROC analyses showed that the VMHC value of pSTG/PCC showed a good sensibility/specificity to differentiate the amusics from the controls. These findings provide a new perspective for understanding the neural basis of congenital amusia and imply the immature state of DMN may be a credible neural marker of amusia.

Gradually Increased Interhemispheric Functional Connectivity During One Night of Sleep Deprivation.

BackgroundIt is well known that circadian rhythms and sleep homeostasis contribute to a pronounced trough in sleepiness and behavioral performance at night. However, the underlying neuroimaging mechanisms remain unclear. How brain-function connectivity is modulated during sleep deprivation (SD) has been rarely examined.MethodsBy increasing the number of scanning sessions during SD, the current study used voxel-mirrored homotopic connectivity (VMHC) to investigate dynamic changes in interhemispheric communication during one night of SD. Every 2 hours from 10 pm to 06 am (session 1, 10 pm; session 2, 12 am; session 3, 2 am; session 4, 4 am; session 5, 6 am), functional magnetic resonance–imaging data and Stanford Sleepiness Scale (SSS) scores were collected from 36 healthy participants with intermediate chronotype. Dynamic changes in SSS scores and VMHC were determined using one-way repeated-measure ANOVA with the false discovery–rate method to correct for multiple comparisons.ResultsSignificant time effects for VMHC were found mainly in the bilateral thalamus, bilateral superior temporal gyrus, and bilateral precentral gyrus. SSS scores and VMHC in these areas were both found to be monotonously increased during SD. Furthermore, significant positive associations were found between SSS valu and VMHC values in the left superior temporal and right superior gyri.ConclusionThese findings might represent the dynamic modulation of circadian rhythm merely or the interaction effects of both circadian rhythm and sleep homeostasis on interhemispheric connectivity within the thalamus, default-mode network, and sensorimotor network. Our study provides more comprehensive information on how SD regulates brain connectivity between hemispheres and adds new evidence of neuroimaging correlates of increased sleepiness after SD.

Decreased Resting-State Interhemispheric Functional Connectivity in Medication-Free Obsessive-Compulsive Disorder.

ObjectiveDecreased homotopic connectivity of brain networks such as the cortico-striato-thalamo-cortical (CSTC) circuits may contribute to the pathophysiology of obsessive-compulsive disorder (OCD). However, little is known about interhemispheric functional connectivity (FC) at rest in OCD. In this study, the voxel-mirrored homotopic connectivity (VMHC) method was applied to explore interhemispheric coordination at rest in OCD.MethodsForty medication-free patients with OCD and 38 sex-, age-, and education level-matched healthy controls (HCs) underwent a resting-state functional magnetic resonance imaging. The VMHC and support vector machine (SVM) methods were used to analyze the data.ResultsPatients with OCD had remarkably decreased VMHC values in the orbitofrontal cortex, thalamus, middle occipital gyrus, and precentral and postcentral gyri compared with HCs. A combination of the VMHC values in the thalamus and postcentral gyrus could optimally distinguish patients with OCD from HCs.ConclusionsOur findings highlight the contribution of decreased interhemispheric FC within and outside the CSTC circuits in OCD and provide evidence to the pathophysiology of OCD.

Alterations of Functional Connectivity in Stroke Patients With Basal Ganglia Damage and Cognitive Impairment.

Background: Stroke with basal ganglia damage (SBG) is a neurological disorder characterized by cognitive impairment. The neurobiological mechanism of cognitive impairment in stroke patients with basal ganglia damage (SBG patients) remains unclear. This study aimed to explore the underlying neurobiological mechanism of cognitive impairment in SBG patients using resting-state functional magnetic resonance imaging (rs-fMRI).Methods: The differences in functional connectivity (FC) between 14 SBG patients (average age: 61.00 ± 7.45 years) and 21 healthy controls (HC) (average age: 60.67 ± 6.95 years) were examined using voxel-mirrored homotopic connectivity (VMHC) and degree centrality (DC). Moreover, we compared the cognitive functions of SBG patients with HC using the Chinese Revised Wechsler Adult Intelligence Scale (WAIS-RC) and Wechsler Memory Scale (WMS).Results: Full-scale intelligence quotient (FIQ) (t = 2.810, p < 0.010) and memory quotient (MQ) (t = 2.920, p < 0.010) scores of SBG patients were significantly lower than those of HC. Compared with HC, significantly decreased VMHC values in the bilateral angular gyrus, supramarginal gyrus, inferior frontal gyrus, middle temporal gyrus, hippocampus, precuneus, precentral gyrus, and middle occipital gyrus and decreased DC values in the right supramarginal gyrus, bilateral angular gyrus, and right postcentral gyrus were observed in SBG patients. Moreover, the VMHC values in the angular gyrus, inferior frontal gyrus, supramarginal gyrus, and middle temporal gyrus and the DC values in the right supramarginal gyrus were significantly correlated with cognitive functions in all participants.Conclusion: Our findings may provide a neural basis for cognitive impairments in SBG patients. Furthermore, local abnormalities of functional networks and interhemispheric interaction deficits may provide new ideas and insights for understanding and treating SBG patients' cognitive impairments.

Modulation of Interhemispheric Functional Coordination in Breast Cancer Patients Receiving Chemotherapy.

ObjectivesChemotherapy induces cognitive impairments including memory impairment attention deficit and executive dysfunction in patients with breast cancer (BC) during or after chemotherapy. Previous studies identified brain structural and functional changes in BC patients receiving chemotherapy; however, there are no studies assessing functional connectivity (FC) between homotopic brain regions in BC patients using a voxel-mirrored homotopic connectivity (VMHC) method. In the present study, we explored cognitive function and whole brain homotopic FC in BC patients receiving chemotherapy compared with healthy controls using the VMHC method.MethodsThe present cross-sectional study included 35 premenopausal women with breast cancer who received chemotherapy, as well as 32 age- and sex-matched healthy controls (HC). All subjects underwent resting-state functional magnetic resonance imaging, which measured homotopic brain FC, and cognitive neuropsychological assessments evaluating attention, memory, and executive function domains.ResultsThe BC group had lower VMHC than the HC group in the cingulated posterior, insular and postcentral regions. No region exhibited higher VMHC in the BC group than in HC group. Correlation analysis in the BC group indicated that VMHC values in the cingulated posterior were significantly correlated with executive function tests, and that the VMHC values in the insular were significantly correlated with memory tests.ConclusionThe present study showed that VMHC decreased in different brain regions including cingulated posterior, insular and postcentral regions. A significant correlation was observed between the VMHC values in the brain regions and neuropsychological tests. These results suggested that changes in VMHC values in different brain regions may underlie cognitive changes in BC patients receiving chemotherapy.

Altered interhemispheric synchrony in Parkinson\u2019s disease patients with levodopa-induced dyskinesias

Levodopa-induced dyskinesias are common motor complication of Parkinson’s disease after 4–6 years of treatment. The hallmarks of dyskinesias include unilateral onset and the tendency to appear on the more affected body sides. There is a growing literature documenting the lateralization abnormalities are associated with the emergence of dyskinesias. Our investigation aimed to explore interhemispheric functional and its corresponding morphological asymmetry. A total of 22 dyskinetic patients, 23 nondyskinetic patients, and 26 controls were enrolled. Resting-state functional magnetic resonance imaging scans were performed twice before and after dopaminergic medication. Voxel-mirrored Homotopic Connectivity (VMHC) and Freesurfer were employed to assess the synchronicity of functional connectivity and structural alternations between hemispheres. During OFF state, dyskinetic patients showed desynchronization of inferior frontal cortex (IFC) when compared to nondyskinetic patients. And during ON state, dyskinetic patients showed desynchronization of IFC and pre-supplementary motor area (pre-SMA) when compared to nondyskinetic patients. However, there was no corresponding significant asymmetries in cortical thickness. Moreover, the degree of desynchronization of IFC and pre-SMA in dyskinetic pateients during ON state were negatively correlated with the Abnormal Involuntary Movement Scale (AIMS) scores. Notably, among patients who showed asymmetrical dyskinesias, there was a significant negative correlation between VMHC values of IFC and dyskinesias symptom asymmetry. Our findings suggested that uncoordinated inhibitory control over motor circuits may underlie the neural mechanisms of dyskinesias in Parkinson’s disease and be related to its severity and lateralization.

Brain Homotopic Connectivity in Mild Cognitive Impairment APOE-ε4 Carriers

Individuals with mild cognitive impairment (MCI) are regarded as being at high risk of developing Alzheimer's disease (AD). The apolipoprotein E (APOE) ε4 allele is a well-established genetic risk factor for developing AD. In the present study, by using voxel-mirrored homotopic connectivity (VMHC), we aimed to explore the potential functional disruptions in MCI APOE-ε4 carriers. Resting-state functional magnetic resonance imaging was performed in 35 MCI APOE-ε4 carriers (27 APOE-ε3ε4, 8 APOE-ε4ε4) and 42 MCI APOE-ε4 noncarriers (APOE-ε3ε3). VMHC was employed to investigate the alterations in functional connectivity in MCI APOE-ε4 carriers. We further investigated the seed-based functional connectivity between the VMHC values of altered regions and other brain regions in the two groups. The results showed that MCI APOE-ε4 carriers presented increased VMHC in the inferior frontal gyrus/insula and middle frontal gyrus/superior frontal gyrus in comparison with noncarriers. We found that MCI APOE-ε4 carriers showed increased functional connectivity between the seed regions (bilateral inferior frontal gyri/insula and bilateral middle frontal gyri/superior frontal gyri) and broad brain areas, including the frontal, temporal, parietal, and cerebellar regions. Our findings provide neuroimaging evidence for the modulation of the APOE genotype on the neurodegenerative disease phenotype and may be potentially important for monitoring disease progression in double-high-risk populations of AD.

Structural remodeling secondary to functional remodeling in advanced-stage peripheral facial neuritis.

Structural remodeling is a classic manifestation of disease decompensation. Facial synkinesis is the most troubling sequela of peripheral facial neuritis, and its structural remodeling, especially in white matter (WM), is still poorly understood. Therefore, understanding WM microstructure is important for predicting WM pathology and for early intervention in facial synkinesis patients. A total of 20 facial synkinesis patients (18 men and 2 women; mean age, 33.35 ± 6.97years old) and 19 healthy controls (17 men and 2 women; mean age, 33.21 ± 6.75years old) were enrolled in this study. rs-fMRI data, diffusion tensor imaging (DTI) data, and Beck's Depression Inventory (BDI) data were collected, and tract-based spatial statistics (TBSS) and voxel-mirrored homotopic connectivity (VMHC) values were used to analyze changes in WM microstructure and interhemispheric coordination. Compared with the healthy controls, facial synkinesis patients exhibited significantly lower regional fractional anisotropy (FA) in the genu of the corpus callosum and the body of the corpus callosum, significantly higher regional FA in the retrolenticular part of the internal capsule, and significantly decreased VMHC values bilaterally in the orbital inferior frontal gyri, the fusiform gyri, the superior temporal gyri, the superior frontal gyri, and the supplementary motor areas. Furthermore, a lower regional FA in the genu of the corpus callosum was correlated with higher BDI scores in facial synkinesis patients. Structural remodeling, especially changes in white matter microstructure, may be the central mechanism for severe sequelae of peripheral facial neuritis.

Influence of Gonadotropin Hormone Releasing Hormone Agonists on Interhemispheric Functional Connectivity in Girls With Idiopathic Central Precocious Puberty.

Purpose: The pubertal growth suppressive effects of gonadotropin hormone releasing hormone agonists (GnRHa) are well-known, although it remains unclear if long-term GnRHa treatment influences the brain function of treated children. The present study investigated the differences in the homotopic resting-state functional connectivity patterns in girls with idiopathic central precocious puberty (ICPP) with and without GnRHa treatment using voxel-mirrored homotopic connectivity (VMHC).Methods: Eighteen girls with ICPP who underwent 12 months of GnRHa treatment, 40 treatment-naïve girls with ICPP, and 19 age-matched girls with premature thelarche underwent resting-state functional magnetic resonance imaging using a 3T MRI. VMHC method was performed to explore the differences in the resting-state interhemispheric functional connectivity. The levels of serum pubertal hormones, including luteinizing hormone (LH), follicular-stimulating hormone, and estradiol, were assessed. Correlation analyses among the results of clinical laboratory examinations, neuropsychological scales, and VMHC values of different brain regions were performed with the data of the GnRHa treated group.Results: Significant decreases in VMHC of the lingual, calcarine, superior temporal, and middle frontal gyri were identified in the untreated group, compared with the control group. Medicated patients showed decreased VMHC in the superior temporal gyrus, when compared with the controls. Compared to the unmedicated group, the medicated group showed a significant increase in VMHC in the calcarine and middle occipital gyrus. Moreover, a positive correlation was observed between basal LH levels and VMHC of the middle occipital gyrus in medicated patients.Conclusions: These findings indicate that long-term treatment with GnRHa was associated with increased interhemispheric functional connectivity within several areas responsible for memory and visual process in patients with ICPP. Higher interhemispheric functional connectivity in the middle occipital gyrus was related to higher basal LH production in the girls who underwent treatment. The present study adds to the growing body of research associated with the effects of GnRHa on brain function.

Aberrant resting-state interhemispheric functional connectivity in patients with postpartum depression

The aim of this study is to investigate the alterations of interhemispheric functional connectivity in patients with postpartum depression (PPD) during resting state, and their potential correlations with clinical severity. Twenty- eight patients with PPD and twenty-five matched healthy postpartum (HP) women within 4 weeks after delivery were recruited and performed resting-state functional magnetic resonance imaging(fMRI) scans. Voxel-mirrored homotopic connectivity (VMHC), which is useful for exploring interhemispheric functional connectivity, and has been widely utilized to identify abnormal functional connectivity between the symmetrical brain regions in many diseases, was calculated in the present study, and intergroup VMHC differences in the voxel manner were analyzed. Correlations between VMHC values and clinical variables were also analyzed. Compared with HP, patients with PPD exhibited significantly decreased VMHC values in bilateral dorsomedial prefrontal cortex (dmPFC), dorsal anterior cingulate cortex (dACC) and orbitofrontal cortex (OFC). Furthermore, VMHC values within the dmPFC negatively correlated with the Edinburgh postpartum depression scale (EPDS) score. These findings suggested that functional coordination between several homotopic brain regions were impaired in patients with PPD. This study provided evidences of aberrant interhemispheric connectivity within brain regions involved in the maternal care network in PPD, and may contribute to the further understanding of the neural mechanism underlying PPD.

Disrupted interhemispheric functional coordination in patients with chronic low back-related leg pain: a multiscale frequency-related homotopic connectivity study.

ObjectiveChronic low back pain has been observed to decrease movement coordination. However, it is unclear whether the existing alteration of inter-hemispheric synchrony of intrinsic activity in patients with chronic low back-related leg pain (cLBLP). The present study aims to investigate the alteration of homotopic connectivity and its clinical association with the cLBLP patients.Participants and methodsA cohort of cLBLP patients (n=25) and well-matched healthy controls (HCs) (n=27) were recruited and underwent MRI scanning and a battery of clinical tests. The voxel-mirrored homotopic connectivity (VMHC) was used to analyze the interhemispheric coordination in the typical (0.01–0.1 Hz) as well as five specific (slow-6 to slow-2) frequency bands and associated with clinical index in cLBLP patients.ResultsWe observed that cLBLP patients with lower homotopic connectivity than HCs in the inferior temporal gyrus, the superior temporal gyrus, the basal ganglia, the middle frontal gyrus, and the medial prefrontal cortex in the typical and five specific frequency bands, respectively. In the typical and five specific frequency bands, significant positive correlations were observed between the VMHC values of medial prefrontal cortex and the visual analogue scale scores, while the VMHC values of basal ganglia negative correlated with the values of two-point tactile discrimination (2PD) test for the right hand in cLBLP patients, etc. Further receiver operating characteristic curve analysis revealed that VMHC in the above regions with decreased could be used to differentiate the cerebral functional plasticity of cLBLP from healthy individuals with high sensitivity and specificity.ConclusionOur results imply that multiscale frequency-related interhemispheric disconnectivity may underlie the central pathogenesis of functional coordination in patients with cLBLP.

Impaired interhemispheric synchrony in late blindness.

Background Several neuroimaging studies demonstrated that visual deprivation led to significant cross-modal plasticity in the brain’s functional and anatomical architecture. Purpose To investigate the pattern of the interhemispheric functional connectivity in individuals with late blindness using the voxel-mirrored homotopic connectivity (VMHC) and seed-based functional connectivity (FC) methods. Material and Methods Forty-four individuals with late blindness (22 men, 22 women; mean age = 39.88 ± 12.84 years) and 55 sighted control individuals (35 men, 20 women; mean age = 43.13 ± 13.98 years)—closely matched for age, sex, and education—underwent resting-state magnetic resonance imaging scans. The VMHC and seed-based FC methods were applied to assess interhemispheric coordination in a voxel-wise manner. Results Compared with the sighted control groups, the late blindness groups showed decreased VMHC values in the bilateral cuneus/calcarine/lingual gyrus (CUN/CAL/LING) (BA 17/18/19) (voxel level: P &lt; 0.001, Gaussian random field [GRF] correction, cluster level: P &lt; 0.005). Meanwhile, for seed-based FC analysis, compared with the sighted control group, the late blindness group showed a decreased FC between the right lower VMHC regions and the bilateral CUN/LING/CAL/precuneus (PreCUN)/left middle occipital gyrus (MOG) (BA 18/19/30/31) and left precentral gyrus (PreCG) and postcentral gyrus (PostCG) (BA 2/3/4/6). The late blindness group showed a decreased FC between the left lower VMHC regions and the bilateral CUN/LING/CAL/PreCUN (BA 18/19/31) and left PreCG and PostCG (BA 2/3/4/6) relative to the sighted control group (voxel level: P &lt; 0.001, GRF correction, cluster level: P &lt; 0.005). Moreover, a negative correlation was observed between the duration of blindness and VMHC values in the bilateral CUN/CAL/LING (r = −0.393, P = 0.008) in individuals with late blindness. Conclusion Our results indicated that late blindness induced substantial impairment of interhemispheric coordination in the visual cortex. This might reflect impaired visual fusion, visual recognition function, and top-down modulations in individuals with late blindness.

Alterations of Interhemispheric Functional Connectivity and Degree Centrality in Cervical Dystonia: A Resting-State fMRI Study.

Background Cervical dystonia (CD) is a neurological movement disorder characterized by involuntary head and neck movements and postures. Reports on microstructural and functional abnormalities in multiple brain regions not limited to the basal ganglia have been increasing in patients with CD. However, the neural bases of CD are unclear. This study is aimed at identifying cerebral functional abnormalities in CD by using resting-state functional magnetic resonance imaging (rs-fMRI). Methods Using rs-fMRI data, voxel-mirrored homotopic connectivity (VMHC) and degree centrality were used to compare the alterations of the rs-functional connectivity (FC) between 19 patients with CD and 21 healthy controls. Regions showing abnormal FCs from two measurements were the regions of interest for correlation analyses. Results Compared with healthy controls, patients with CD exhibited significantly decreased VMHC in the supplementary motor area (SMA), precuneus (PCu)/postcentral gyrus, and superior medial prefrontal cortex (MPFC). Significantly increased degree centrality in the right PCu and decreased degree centrality in the right lentiform nucleus and left ventral MPFC were observed in the patient group compared with the control group. Further correlation analyses showed that the VMHC values in the SMA were negatively correlated with dystonia severity. Conclusion Local abnormalities and interhemispheric interaction deficits in the sensorimotor network (SMA, postcentral gyrus, and PCu), default mode network (MPFC and PCu), and basal ganglia may be the key characteristics in the pathogenesis mechanism of CD.

Abnormalities of interhemispheric functional connectivity in individuals with acute eye pain: a resting-state fMRI study.

To study the changes of the resting state functional connectivity (rsFC) between acute eye pain (EP) subjects and healthy controls (HCs) in the two hemispheres by using voxel-mirrored homotopic connectivity (VMHC) method. Totally 20 patients with EP and 20 HCs were enrolled, sex, age, and education were matched, and all subjects were examined by functional magnetic resonance imaging (fMRI) scans at resting-state. The changes of rsFC between the hemispheres were evaluated by the VMHC method according to Gaussian random field (GRF) theory. In order to identify the VMHC, as biomarkers for distinguishing EP and from HC, the receiver operating characteristic curves (ROC) had been analyzed. The relationships were evaluated with Pearson correlation analysis between the mean VMHC signal values and clinical features in these patients. By comparing with health subjects, the significant decreased VMHC values was observed in lingual/calcarine (Brodmann area, BA 30), precentral/postcentral gyrus (PreCG/PosCG; BA 4) and medial frontal gyrus (MFG; BA 8) (false discovery rate corrected <0.01) in the acute EP individuals. The accuracy of area under curve was excellent indicated by the ROC curve analysis of each brain regions. Our study demonstrates preliminary evidence of disrupted interhemispheric rsFC in acute EP in sensorimotor and limbic system and somatosensory cortex, which might give some useful information for understanding the neurological mechanisms in acute EP individuals.

Alternations of interhemispheric functional connectivity in corneal ulcer patients using voxel-mirrored homotopic connectivity: a resting state fMRI study.

Background Corneal ulcer (CU) is the second ocular disease leading to blindness. Millions of people around the world suffer from CU. However, the relationship between CU and altered functional connectivity in the brain is still unknown. Purpose The aim of the present study was to investigate the alterations of the brain interhemispheric functional connectivity (FC) in patients with CU using the voxel-mirrored homotopic connectivity (VMHC) method and their relationship with clinical manifestations. Material and Methods The present study involved 24 patients with CU (12 men, 12 women) and 24 healthy controls (HCs) with their age, sex, and weight closely matched. Independent sample t-test, VMHC method, and Pearson’s correlation analysis were applied. Receiver operating characteristic (ROC) curve analysis was used to estimate the effect in distinguishing CU patients from HCs. Results The CU patients showed decreased VMHC values in bilateral lingual/calcarine, precentral/postcentral gyrus, and medial frontal gyrus compared with HCs. There were positive correlations between Visual Analogue Score (VAS) and VMHC values of bilateral media frontal gyrus ( r = 0.654, p = 0.001), the best-corrected VA of the affected eye and VMHC values of the bilateral lingual/calcarine region ( r = 0.960, p &lt; 0.001). ROC curve also showed high diagnostic values in those regions. Conclusion Our study was the first to explore FC changes in CU patients’ brains using VMHC methods. We demonstrated that ocular pain of CU patients had a close relationship with altered VMHC values. Decreased VMHC values in the brain of CU patients may be useful markers to reflect the condition of progress in patients with CU.

Voxel-Mirrored Homotopic Connectivity of Resting-State Functional Magnetic Resonance Imaging in Blepharospasm

Objective: Several networks in human brain are involved in the development of blepharospasm. However, the underlying mechanisms for this disease are poorly understood. A voxel-mirrored homotopic connectivity (VMHC) method was used to quantify the changes in functional connectivity between two hemispheres of the brain in patients with blepharospasm.Methods: Twenty-four patients with blepharospasm and 24 healthy controls matched by age, sex, and education were recruited. The VMHC method was employed to analyze the fMRI data. The support vector machine (SVM) method was utilized to examine whether these abnormalities could be applied to distinguish the patients from the controls.Results: Compared with healthy controls, patients with blepharospasm showed significantly high VMHC in the inferior temporal gyrus, interior frontal gyrus, posterior cingulate cortex, and postcentral gyrus. No significant correlation was found between abnormal VMHC values and clinical variables. SVM analysis showed a combination of increased VMHC values in two brain areas with high sensitivities and specificities (83.33 and 91.67% in the combined inferior frontal gyrus and posterior cingulate cortex; and 83.33 and 87.50% in the combined inferior temporal gyrus and postcentral gyrus).Conclusion: Enhanced homotopic coordination in the brain regions associated with sensory integration networks and default-mode network may be underlying the pathophysiology of blepharospasm. This phenomenon may serve as potential image markers to distinguish patients with blepharospasm from healthy controls.