Disturbed spontaneous brain-activity pattern in patients with optic neuritis using amplitude of low-frequency fluctuation: a functional magnetic resonance imaging study

Amplitude of Low-Frequency Fluctuation to Determine Disturbed Spontaneous Brain-Activity Pattern in Patients with Diabetic Optic Neuropathy

Purpose

This study aimed to explore the spontaneous brain activity in patients with diabetic optic neuropathy (DON) by using the amplitude of low-frequency fluctuation (ALFF) technique.

Methods

Sixteen DON patients and 16 age- and sex-matched healthy controls (HCs) were recruited. ALFF along with functional MRI method was used to detect the intrinsic brain activity alterations. The mean values of ALFF in DON patients and HCs were analyzed by receiver operating characteristic (ROC) curves. Pearson's correlation analysis was used to determine the correlation between Hospital Anxiety and Depression Scale (HADS) and ALFF values of DONs.

Results

The DON group showed significantly increased ALFF values in the fusiform gyrus, and decreased ALFF values in the medial frontal gyrus/left frontal superior orbit/right frontal medial orbit, and left frontal inferior triangle. ROC curve analysis indicated that the accuracy of AUC was good. The anxiety scale and depression scale of the DON group were negatively correlated with the ALFF values of the medial frontal gyrus.

Conclusion

DON is a neurodegenerative disease involving multiple brain regions. The abnormal activity of neurons in these brain regions helps to reveal the underlying neural mechanisms of brain activity related to DON.

Resting-state functional MRI of the visual system for characterization of optic neuropathy

Optic neuropathy refers to disease of the optic nerve and can result in loss of visual acuity and/or visual field defects. Combining findings from multiple fMRI modalities can offer valuable information for characterizing and managing optic neuropathies. In this article, we review a subset of resting-state functional magnetic resonance imaging (RS-fMRI) studies of optic neuropathies. We consider glaucoma, acute optic neuritis (ON), discuss traumatic optic neuropathy (TON), and explore consistency between findings from RS and visually driven fMRI studies. Consistent with visually driven studies, glaucoma studies at rest also indicated reduced activation in the visual cortex and dorsal visual stream. RS-fMRI further reported varying levels of functional connectivity in the ventral stream depending on disease severity. ON patients show alterations within the visual cortex in both fMRI techniques. Particularly, higher-than-normal RS activity is observed in the acute phase and decreases as the disease progresses. A similar pattern is observed in the visual cortex of TON-like, open globe injury (OGI), patients. Additionally, visually driven and RS-fMRI studies of ON patients show recovery of brain activity in the visual cortex. RS-fMRI suggests recovery of signals in higher-tier visual areas MT and LOC as well. Finally, RS-fMRI has not yet been applied to TON, although reviewing OGI studies suggests that it is feasible. Future RS-fMRI studies of optic neuropathies could prioritize studying the fine scale RS activity of brain areas that visually driven studies have identified. We suggest that a more systematic longitudinal comparison of optic neuropathies with advanced fMRI would provide improved diagnostic and prognostic information.

The Predictive Potential of Altered Voxel-Based Morphometry in Severely Obese Patients With Meibomian Gland Dysfunction

Objective

To investigate voxel-based morphometry (VBM) by using magnetic resonance imaging (MRI) in meibomian gland dysfunction patients with severe obesity (PATs) and to explore the application of VBM in the early diagnosis, prevention of cognitive impairment and targeted treatment of this disease.

Methods

Sixteen PATs and 12 healthy controls (HCs) were enrolled and underwent MRI. Whole-head images were analyzed using VBM and data were compared between groups using an independent samples t-test. Receiver operating characteristic (ROC) curves were utilized to assess the diagnostic value of this approach. Mini-mental state examination (MMSE) scores were used to assess cognitive impairment and were analyzed using an independent samples t-test.

Results

Compared with HCs, the VBM values in PATs were reduced in the left cerebellum and right thalamus but increased in the right brainstem, right precuneus and right paracentral lobule. The results of ROC curve analysis indicated that VBM may be useful in meibomian gland disease diagnosis. Comparison of MMSE scores between groups showed mild cognitive impairment in PATs.

Conclusion

PATs showed altered VBM values in some brain areas. These findings may provide information about the pathophysiology of meibomian gland dysfunction and may help to explain the underlying mechanisms of clinical manifestations in PATs, such as cognitive impairment. Abnormal VBM values in these brain areas may serve as predictive factors for development of meibomian gland disease in severely obese people and as indicators for individualized treatment.

Characteristics of the Fractional Amplitude of Low-Frequency Fluctuation in Ocular Hypertension Patients: A Resting-State fMRI Study

Background

The fractional amplitude of low-frequency fluctuation (fALFF) method has been underutilized in research on the pathogenesis and clinical manifestations of ocular hypertension (OH).

Purpose

This study uses resting state functional magnetic resonance imaging (rs-fMRI) and fALFF to investigate the nature of spontaneous brain activity in OH patients and the relationship, if any, between changes in activity and clinical features.

Materials and Methods

A total of 18 subjects (9 females and 9 males) with ocular hypertension (OH) and 18 healthy controls (HCs) matched for gender, age, and educational level were recruited to this study. All participants underwent an rs-fMRI scan, and spontaneous brain activity was assessed using the fALFF method. Receiver operating characteristic curves were plotted to investigate differences between OH and HC groups.

Results

The fALFF values of OH patients were significantly higher in the left precuneus lobe (LP), compared with the same region in controls (P < 0.05). Conversely, values in the left anterior cingulate lobe (LAC), were significantly lower (P < 0.05) in OH than in controls. However, no significant association was found between the mean fALFF values and clinical characteristics in either brain area.

Conclusion

High spontaneous activity in two brain areas may reflect neuropathological mechanisms underpinning visual impairment in OH patients.

Altered Brain Activity in Patients With Comitant Strabismus Detected by Analysis of the Fractional Amplitude of Low-Frequency Fluctuation: A Resting-State Functional MRI Study

More and more studies showed that strabismus is not simply an ocular disease, but a neuro-ophthalmology disease. To analyze potential changes in brain activity and their relationship to behavioral performance in comitant strabismus patients and healthy controls. Our study recruited 28 patients with comitant strabismus and 28 people with matched weight, age range, and sex ratio as healthy controls. Using resting-state functional magnetic resonance imaging, we evaluated fALFF to compare spontaneous brain activity between comitant strabismus and healthy controls. We did hospital anxiety and depression scale questionnaires for these patients. We found significantly lower fALFF value in comitant strabismus patients compared with controls in the left frontal superior medial gyrus and the right middle cingulum. In the latter region, fALFF was significantly negatively correlated with the hospital anxiety and depression scale, as well as the duration of disease. Receiver operating characteristic curve analysis indicated that the fALFF method has clear potential for the diagnosis of comitant strabismus patients. These results revealed abnormal spontaneous activity in two brain regions of comitant strabismus patients, which may indicate underlying pathologic mechanisms and may help to advance clinical treatment.

Abnormal Intrinsic Functional Hubs in Corneal Ulcer: Evidence from a Voxel-Wise Degree Centrality Analysis

BACKGROUND

Numerous anterior neuroimaging researches have revealed that corneal ulcers (CU) are related to changes in cerebral anatomic structure and functional area. Nonetheless, functional characteristics of the brain's network organization still show no definite research results. The study was designed to confirm CU-associated spatial centrality distribution functional network of the whole cerebrum and explore the mechanism through which the larvaceous changed the intrinsic functional hubs.

MATERIAL AND METHODS

In this study, 40 patients with CU and 40 normal controls (matched in sex, age, and education level) were enrolled in this study to undergo resting-state functional magnetic resonance imaging (fMRI) scans. The differences between the groups were determined by measuring the voxel-wise degree centrality (DC) throughout the whole cerebrum. For the purpose of assessing the correlation between abnormal DC value and clinical variables, the Linear correlation analysis was used.

RESULTS

Compared with normal controls (NCs), CU patients revealed high DC values in the frontal lobe, precuneus, inferior parietal lobule, posterior cingulate, occipital lobe, and temporal lobe in the brain functional connectivity maps throughout the brain. The intergroup differences also had high similarity on account of different thresholds. In addition, DC values were positively related to the duration of CU in the left middle frontal gyrus.

CONCLUSIONS

The experimental results revealed that patients with CU showed spatially unnatural intrinsic functional hubs whether DC values increased or decreased. This brings us to a new level of comprehending the functional features of CU and may offer useful information to make us obtain a clear understanding of the dysfunction of CU.

Altered spontaneous brain activity patterns in patients with hyperthyroidism exophthalmos using amplitude of low-frequency fluctuation: a resting-state fMRI study

AIM

To assess changed spontaneous brain activity in hyperthyroid exophthalmos (HE) patients by the amplitude of the low-frequency fluctuation (ALFF) method, and to analyze the correlation between brain activity and ALFF values in these patients.

METHODS

Totally 18 HE and 18 hyperthyroid non-exophthalmos (HNE) patients were enrolled. The participants were tested by resting-state functional magnetic resonance imaging, and receiver operating characteristic (ROC) curves were generated to classify the ALFF values of the study population. Pearson's correlation analysis was utilized to evaluate the relationship between the ALFF values obtained from different brain areas and clinical manifestations.

RESULTS

Contrary to HNE patients, we observed lower ALFF values in the left calcarine fissure and surrounding cortex (LCFSC) in HE patients. In the ROC curve analysis of the LCFSC, the area under the curve reflected a high degree of accuracy. In addition, there was positive correlation between mean ALFF values of the LCFSC and the best-corrected visual acuity of the affected eyes.

CONCLUSION

The study displays abnormal brain activity in LCFSC in patients with HE, which might suggest pathological mechanism of visual impairment of HE patients.

Resting-State Functional Magnetic Resonance Imaging and Functional Connectivity Density Mapping in Patients With Optic Neuritis

Background: Using resting-state functional connectivity (rsFC), we investigated alternations in spontaneous brain activities reflected by functional connectivity density (FCD) in patients with optic neuritis (ON).

Methods: We enrolled 28 patients with ON (18 males, 10 females) and 24 healthy controls (HCs; 16 males, 8 females). All subjects underwent functional magnetic resonance imaging (fMRI) in a quiet state to determine the values of rsFC, long-range FCD (longFCD), and short-range FCD (IFCD). Receiver operating characteristic (ROC) curves were generated to distinguish patients from HCs.

Results: The ON group exhibited obviously lower longFCD values in the left inferior frontal gyrus triangle, the right precuneus and the right anterior cingulate, and paracingulate gyri/median cingulate and paracingulate gyri. The left median cingulate and paracingulate gyri and supplementary motor area (SMA) were also significantly lower. Obviously reduced IFCD values were observed in the left middle temporal gyrus/angular gyrus/SMA and right cuneus/SMA compared with HCs.

Conclusion: Abnormal neural activities were found in specific brain regions in patients with ON. Specifically, they showed significant changes in rsFC, longFCD, and IFCD values. These may be useful to identify the specific mechanism of change in brain function in ON.

Alternations of interhemispheric functional connectivity in children with strabismus and amblyopia: a resting-state fMRI study

Previous neuroimaging studies demonstrated that patients with strabismus or amblyopia can show significant functional and anatomical changes in the brain, but alterations of interhemispheric functional connectivity (FC) have not been well studied in this population. The current study analyzed whole-brain changes of interhemispheric FC in children with strabismus and amblyopia (CSA) using voxel-mirrored homotopic connectivity (VMHC).A total of 24 CSA (16 males and 8 females) and 24 normal controls (NCs) consisting of 16 and 8 age-, sex, and education-matched males and females, respectively, underwent functional magnetic resonance imaging (fMRI) scans in the resting state. According to Gaussian random field theory, changes in the resting state FC (rsFC) between hemispheres were evaluated using the VMHC method. The relationships between mean VMHC values in multiple brain regions and behavioral performance were evaluated by Pearson correlation analysis. In contrast to NCs, the CSA group showed significantly decreased VMHC values in the bilateral cerebellum, bilateral frontal superior orbital (frontal sup orb), bilateral temporal inferior(temporal inf),and bilateral frontal superior(frontal sup). CSA have abnormal interhemispheric FC in many brain regions, which may reflect dysfunction of eye movements and visual fusion. These findings might provide insight into the underlying pathogenetic mechanisms of CSA.

Altered Small-World Functional Network Topology in Patients with Optic Neuritis: A Resting-State fMRI Study

Aim

This study investigated changes in small-world topology and brain functional connectivity in patients with optic neuritis (ON) by resting-state functional magnetic resonance imaging (rs-fMRI) and based on graph theory.

Methods

A total of 21 patients with ON (8 males and 13 females) and 21 matched healthy control subjects (8 males and 13 females) were enrolled and underwent rs-fMRI. Data were preprocessed and the brain was divided into 116 regions of interest. Small-world network parameters and area under the integral curve (AUC) were calculated from pairwise brain interval correlation coefficients. Differences in brain network parameter AUCs between the 2 groups were evaluated with the independent sample t-test, and changes in brain connection strength between ON patients and control subjects were assessed by network-based statistical analysis.

Results

In the sparsity range from 0.08 to 0.48, both groups exhibited small-world attributes. Compared to the control group, global network efficiency, normalized clustering coefficient, and small-world value were higher whereas the clustering coefficient value was lower in ON patients. There were no differences in characteristic path length, local network efficiency, and normalized characteristic path length between groups. In addition, ON patients had lower brain functional connectivity strength among the rolandic operculum, medial superior frontal gyrus, insula, median cingulate and paracingulate gyri, amygdala, superior parietal gyrus, inferior parietal gyrus, supramarginal gyrus, angular gyrus, lenticular nucleus, pallidum, superior temporal gyrus, and cerebellum compared to the control group (P < 0.05).

Conclusion

Patients with ON show typical "small world" topology that differed from that detected in HC brain networks. The brain network in ON has a small-world attribute but shows reduced and abnormal connectivity compared to normal subjects and likely causes symptoms of cognitive impairment.

Altered Functional Connectivity of the Primary Visual Cortex in Patients With Iridocyclitis and Assessment of Its Predictive Value Using Machine Learning

Purpose

To explore the intrinsic functional connectivity (FC) alteration of the primary visual cortex (V1) between individuals with iridocyclitis and healthy controls (HCs) by the resting-state functional magnetic resonance imaging (fMRI) technique, and to investigate whether FC findings be used to differentiate patients with iridocyclitis from HCs.

Methods

Twenty-six patients with iridocyclitis and twenty-eight well-matched HCs were recruited in our study and underwent resting-state fMRI examinations. The fMRI data were analyzed by Statistical Parametric Mapping (SPM12), Data Processing and Analysis for Brain Imaging (DPABI), and Resting State fMRI Data Analysis Toolkit (REST) software. Differences in FC signal values of the V1 between the individuals with iridocyclitis and HCs were compared using independent two-sample t-tests. Significant differences in FC between two groups were chosen as classification features for distinguishing individuals with iridocyclitis from HCs using a support vector machine (SVM) classifier that involved machine learning. Classifier performance was evaluated using permutation test analysis.

Results

Compared with HCs, patients with iridocyclitis displayed significantly increased FC between the left V1 and left cerebellum crus1, left cerebellum 10, bilateral inferior temporal gyrus, right hippocampus, and left superior occipital gyrus. Moreover, patients with iridocyclitis displayed significantly lower FC between the left V1 and both the bilateral calcarine and bilateral postcentral gyrus. Patients with iridocyclitis also exhibited significantly higher FC values between the right V1 and left cerebellum crus1, bilateral thalamus, and left middle temporal gyrus; while they displayed significantly lower FC between the right V1 and both the bilateral calcarine and bilateral postcentral gyrus (voxel-level P<0.01, Gaussian random field correction, cluster-level P<0.05). Our results showed that 63.46% of the participants were correctly classified using the leave-one-out cross-validation technique with an SVM classifier based on the FC of the left V1; and 67.31% of the participants were correctly classified based on the FC of the right V1 (P<0.001, non-parametric permutation test).

Conclusion

Patients with iridocyclitis displayed significantly disturbed FC between the V1 and various brain regions, including vision-related, somatosensory, and cognition-related regions. The FC variability could distinguish patients with iridocyclitis from HCs with substantial accuracy. These findings may aid in identifying the potential neurological mechanisms of impaired visual function in individuals with iridocyclitis.

Altered spontaneous brain activity patterns in patients with neovascular glaucoma using amplitude of low-frequency fluctuations: A functional magnetic resonance imaging study

BACKGROUND

Neovascular glaucoma (NVG) can cause irreversible visual impairment and abnormal spontaneous changes in brain's visual system and other systems. There is little research on this aspect at present. However, amplitude of low-frequency fluctuations (ALFFs) can be used as an rs-fMRI analysis technique for testing changes in spontaneous brain activity patterns.

PURPOSE

The aim of this study was to probe the local characteristics of spontaneous brain activity in NVG patients and analyze their correlation with clinical behaviors.

METHODS

Resting-state functional magnetic resonance imaging (rs-fMRI) scans were obtained from eighteen patients with NVG (8 males, 10 females) and eighteen healthy controls (HCs; 8 males and 10 females) who were matched in age, gender, and education level. We evaluated spontaneous brain activity with the ALFF method. A receiver operating characteristic (ROC) curve was used to compare the average ALFF values for altered brain regions of NVG patients with those of HCs.

RESULTS

Compared with HCs, NVG patients had lower ALFF values in the right cuneus, right middle occipital gyrus, left cingulate gyrus, right precuneus, and left medial frontal gyrus (p < 0.001). Higher ALFF values were observed in the right superior frontal gyrus and left middle frontal gyrus (p < 0.001). Analysis of the ROC curves of the brain regions showed that the specificity and accuracy of ALFF values between NVG and HCs in the area under the curve were acceptable (p < 0.001).

CONCLUSION

The patients with NVG exhibited anomalous spontaneous activity in different brain regions; these finding should establish the foundation for a more comprehensive understanding of the pathological mechanisms of NVG. Furthermore, these abnormal variations in specific brain regions can be considered possible clinical indices of NVG.

Abnormal Fractional Amplitude of Low-Frequency Fluctuation Changes in Patients with Monocular Blindness: A Functional Magnetic Resonance Imaging (MRI) Study

BACKGROUND We used fractional amplitude of low-frequency fluctuation (fALFF) technology to investigate spontaneous cerebral activity in patients with monocular blindness (MB) and in healthy controls (HCs). MATERIAL AND METHODS Thirty MB patient and 15 HCs were included in this study. All subjects were scanned by resting-state functional magnetic resonance imaging (rs-fMRI). The independent sample t test and chi-squared test were applied to analyze demographics of MB patients and HCs. The 2-sample t test and receiver operating characteristic (ROC) curves were applied to identify the difference in average fALFF values between MB patients and HCs. Pearson's correlation analysis was applied to explore the relationship between the average fALFF values of brain areas and clinical behavior in the MB group. RESULTS MB patients had lower fALFF values in the left anterior cingulate and higher fALFF values in the left precuneus and right and left inferior parietal lobes than in HCs. Moreover, the mean fALFF values of MB patients in the left anterior cingulate had negative correlations with the anxiety scale score (r=-0.825, P<0.001) and the depression scale score (r=-0.871, P<0.001). CONCLUSIONS Our study found that MB patients had abnormal spontaneous activities in the visual and vision-related regions. The finding of abnormal neuronal activity helps to reveal the underlying neuropathologic mechanisms of vision loss.

Altered spontaneous brain activity patterns in diabetic patients with vitreous hemorrhage using amplitude of low‑frequency fluctuation: A resting‑state fMRI study

The aim of the present study was to assess the local character of spontaneous brain activity in type-2 diabetic patients with vitreous hemorrhage (VH) and its relationship with clinical features via the amplitude of low-frequency fluctuations (ALFF) method. A total of 31 subjects (15 females and 16 males) with type-2 diabetic VH and 31 normal controls (NCs) with similar characteristics (sex, age and educational level) were recruited in the present study. All subjects underwent resting-state functional magnetic resonance imaging scans. The local character of spontaneous brain activity was assessed using the ALFF method. The difference between the type-2 diabetic patients with VH and NCs was determined using receiver operating characteristic curves. Pearson's correlation analysis was applied to evaluate the relationship between the mean ALFF values of specific brain areas and related clinical manifestations in type-2 diabetic patients with VH. The ALFF values of type-2 diabetic patients with VH were significantly increased in the right and left cerebellum posterior lobes, left cerebellum posterior lobe/left lingual gyrus and bilateral superior frontal gyrus/left postcentral gyrus, compared with those obtained for NCs (P<0.05). By contrast, these values were significantly decreased in the left and right middle frontal gyri, right medial frontal gyrus/left anterior cingulate, right inferior frontal gyrus, right superior frontal gyrus, right middle frontal gyrus, right superior frontal gyrus/middle frontal gyrus and left middle frontal gyrus of the former group compared with the NCs (P<0.05). Nevertheless, there was no significant association between the mean ALFF values and clinical characteristics in different brain areas. Unusual spontaneous activity occurred in multiple brain areas, which may suggest the neuropathological mechanisms of visual impairment in type-2 diabetic patients with VH.

The predictive potential of altered spontaneous brain activity patterns in diabetic retinopathy and nephropathy

Objective

The amplitude of low-frequency fluctuation (ALFF) fMRI technique was used to study the changes of spontaneous brain activity in patients with diabetic retinopathy and nephropathy (DRN), and to explore the application of ALFF technique in the potential prediction and the targeted prevention of diabetic microangiopathy.

Methods

Nineteen patients with diabetic retinopathy and nephropathy and 19 healthy controls (HCs) were matched for age and gender. Spontaneous cerebral activity variations were investigated using the ALFF technique. The average ALFF values of the DRN patients and the HCs were classified utilizing receiver operating characteristic (ROC) curves.

Results

In contrast to the results in the HCs, the patients with DRN had significantly higher ALFF values in the cerebellum (bilaterally in the posterior and anterior lobes) and the left inferior temporal gyrus, but the ALFF values of the bilateral medial frontal gyrus, right superior temporal gyrus, right middle frontal gyrus, left middle/inferior frontal gyrus, bilateral precuneus, and left inferior parietal lobule were lower. ROC curve analysis of each brain region showed the accuracy of AUC was excellent. However, the mean ALFF values in the different regions did not correlate with clinical performance. The subjects showed abnormal neuronal synchronization in many areas of the brain, which is consistent with cognitive and visual functional deficits.

Conclusion

Abnormal spontaneous activity was detected in many areas of the brain, which may provide useful information for understanding the pathology of DRN. Abnormal ALFF values of these brain regions may be of predictive value in the development of early DRN and be a targeted intervention indicator for individualized treatment of diabetic microvascular diseases.

Altered spontaneous brain activity patterns in patients with corneal ulcer using amplitude of low-frequency fluctuation: An fMRI study

The aim of the present study was to investigate the altered spontaneous brain activity in patients with corneal ulcer (CU) through the amplitude of low-frequency fluctuation (ALFF) technique and the association with their visual performance. A total of 40 patients with CU and 40 healthy controls (HCs) matched for sex, age and educational level were enrolled. Resting-state functional magnetic resonance imaging (rs-fMRI) was performed to examine the probands. Spontaneous cerebral activity variations were investigated using the ALFF technique. The average ALFF values of the CU patients and the HCs were classified by utilizing receiver operating characteristic (ROC) curves. Contrary to HCs, the CU patients had significantly lower ALFF values in the left cerebellar anterior lobe, right middle frontal gyrus and left middle frontal gyrus, but higher ALFF values in the right cerebellar inferior lobe, left cerebellar inferior lobe, left inferior temporal gyrus, right fusiform gyrus, left superior frontal gyrus, right angular gyrus and bilateral superior frontal gyrus. ROC curve analysis of each brain region indicated that the accuracy of ALFF value specificity between the CU and HCs of the area under the curve was perfect. In conclusion, abnormal spontaneous activities were detected in numerous brain regions of CU patients, which may provide useful information for understanding the dysfunction of CU. These activity changes in brain regions may be used as effective clinical indicators for CU.

Resting-state functional magnetic resonance imaging (fMRI) and functional connectivity density mapping in patients with corneal ulcer

PURPOSE

To investigate alternations in spontaneous brain activities reflected by functional connectivity density (FCD) in patients with corneal ulcer (CU) using resting-state functional connectivity (rsFC).

METHODS

We recruited 24 patients with CU (12 males, 12 females), and 24 healthy controls (HCs; 12 males, 12 females) matched for age, gender and education status. Functional magnetic resonance imaging examinations were performed on all subjects in a resting state and the following parameters determined: rsFC, long-range FCD (longFCD) and short-range FCD (IFCD). Receiver operating characteristic (ROC) curves were then used to differentiate patients with CU from HCs.

RESULTS

Compared with HCs, CU patients showed significantly reduced rsFC values in the right cerebellum posterior lobe gyrus, right middle frontal gyrus/inferior frontal gyrus/superior frontal gyrus and left inferior parietal lobule/precuneus. Significantly reduced longFCD values were found in the right hippocampus/inferior temporal gyrus and the left inferior temporal gyrus. Moreover, compared with HCs, IFCD values were significantly reduced in the left inferior temporal gyrus/middle temporal gyrus, left limbic lobe/medial frontal gyrus, and left precuneus/limbic lobe, but were significantly increased in the right insula/superior temporal gyrus, left superior temporal gyrus/inferior frontal gyrus/insula, right superior temporal gyrus/postcentral gyrus, and left precentral gyrus.

CONCLUSIONS

Patients with CU exhibited alterations in spontaneous brain activities in several brain areas. These novel findings may help to reveal the neuropathological mechanisms underlying CU.

This study provides a direction for further exploration of underlying neural mechanisms of CU and facilitate the clinical diagnosis and treatment of CU.

Visual cortex neural activity alteration in cervical spondylotic myelopathy patients: a resting-state fMRI study

PURPOSE

We sought to investigate visual cortex neural activity and functional connectivity (FC) alterations in cervical spondylotic myelopathy (CSM) patients using resting-state fMRI (rs-fMRI) and to explore the relationships of these alterations with visual disorder.

METHODS

Twenty-seven CSM patients and 11 healthy controls were recruited as the study and control groups. The amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) values were calculated to represent neural activity, seed-based correlation analysis (SCA) was performed to analyze the FC of visual cortex, and the outcomes were compared between groups. The preoperative best-corrected visual acuity (pre-BCVA) and postoperative BCVA (post-BCVA) of study groups were measured. Correlation analyses of the ALFF/ReHo values with the preoperative and postoperative BCVAs were performed. Correlations of the bilateral BCVAs with the ipsilateral and contralateral visual cortex neural activities were performed.

RESULTS

The ALFF/ReHo values were decreased in the occipital lobe and increased in the cerebellar posterior lobe in the study group (P < 0.05). Increased FC was demonstrated between Brodmann's area 17 and posterior cingulate lobe (P < 0.05). Postoperatively, the BCVAs were ameliorated in 22 oculi dexter (ODs) and 20 oculi sinister (OSs) in the study group. Positive correlations between neural activity in the visual cortex and the preoperative and postoperative BCVAs were detected in the study group. The bilateral BCVAs were positively correlated with either the ipsilateral or contralateral visual cortex neural activity.

CONCLUSION

Both ALFF/ReHo value changes and positive correlations of these changes with BCVA were demonstrated in CSM. The FC between the visual cortex and posterior cingulate lobe was also increased in CSM.

Brain Correlates of Single Trial Visual Evoked Potentials in Migraine: More Than Meets the Eye

Background: Using conventional visual evoked potentials (VEPs), migraine patients were found to be hyperresponsive to visual stimulus. Considering that a significant portion of neuronal activity is lost for analysis in the averaging process of conventional VEPs, in this study we investigated visual evoked responses of migraine patients and healthy volunteers using a different approach: single trial analysis. This method permits to preserve all stimulus-induced neuronal activations, whether they are synchronized or not. In addition, we used MRI voxel-based morphometry to search for cortical regions where gray matter volume correlated with single trial (st) VEP amplitude. Finally, using resting-state functional MRI, we explored the connectivity between these regions. Results: stVEP amplitude was greater in episodic migraine patients than in healthy volunteers. Moreover, in migraine patients it correlated positively with gray matter volume of several brain areas likely involved in visual processing, mostly belonging to the ventral attention network. Finally, resting state functional connectivity corroborated the existence of functional interactions between these areas and helped delineating their directions. Conclusions: st-VEPs appear to be a reliable measure of cerebral responsiveness to visual stimuli. Mean st-VEP amplitude is higher in episodic migraine patients compared to controls. Visual hyper-responsiveness in migraine involves several functionally-interconnected brain regions, suggesting that it is the result of a complex multi-regional process coupled to stimulus driven attention systems rather than a localized alteration.

Baseline Brain Activity Changes in Patients With Single and Relapsing Optic Neuritis

Purpose: To investigate spontaneous brain activity amplitude alterations in single and relapsing optic neuritis (sON and rON, respectively) and their relationships with clinical variables.

Methods: In total, 42 patients with sON, 35 patients with rON and 50 healthy volunteers were recruited. Resting-state functional Magnetic Resonance Imaging (rs-fMRI) scans were acquired for all participants and compared to investigate the changes in the amplitude of low-frequency fluctuations (ALFFs) among the three groups. The relationships between the ALFFs in regions with significant differences in the groups and clinical variables, including the logarithm of minimal angle of resolution (LogMAR), Expanded Disability Status Scale (EDSS) score and disease duration, were further explored.

Results: Compared with healthy volunteers, the sON and rON patients showed significantly decreased ALFFs in several regions of the occipital and temporal lobes (i.e., inferior occipital gyrus and superior temporal gyrus; corrected p < 0.01 using AlphaSim). The sON patients showed significantly increased ALFFs in the left caudate and certain regions in the frontal lobes (i.e., medial frontal gyrus), whereas the rON patients showed increased ALFFs in the bilateral inferior temporal gyrus and left medial frontal gyrus (corrected p < 0.01 using AlphaSim). Significantly decreased ALFFs were observed in the right inferior parietal lobule (IPL), left posterior cingulate and precuneus in the rON patients compared with those in the sON patients (corrected p < 0.01 using AlphaSim). Significant correlations were observed between the disease duration and ALFF in the left middle temporal gyrus, left inferior occipital gyrus, right lingual gyrus and right IPL (p < 0.05).

Conclusion: Functional impairment and adaptation occurred in both the sON and rON patients. Impairment mainly involved the occipital cortex, and functional adaptions predominantly occurred in the frontal lobe. Functional damage was more severe in the rON patients than in the sON patients and correlated with the disease duration.

Altered brain network centrality in patients with adult comitant exotropia strabismus: A resting-state fMRI study

Objective To investigate the underlying functional network brain-activity changes in patients with adult comitant exotropia strabismus (CES) and the relationship with clinical features using the voxel-wise degree centrality (DC) method. Methods A total of 30 patients with CES (17 men, 13 women), and 30 healthy controls (HCs; 17 men, 13 women) matched in age, sex, and education level participated in the study. DC was used to evaluate spontaneous brain activity. Receiver operating characteristic (ROC) curve analysis was conducted to distinguish CESs from HCs. The relationship between mean DC values in various brain regions and behavioral performance was examined with correlation analysis. Results Compared with HCs, CES patients exhibited decreased DC values in the right cerebellum posterior lobe, right inferior frontal gyrus, right middle frontal gyrus and right superior parietal lobule/primary somatosensory cortex (S1), and increased DC values in the right superior temporal gyrus, bilateral anterior cingulate, right superior temporal gyrus, and left inferior parietal lobule. However, there was no correlation between mean DC values and behavioral performance in any brain regions. Conclusions Adult comitant exotropia strabismus is associated with abnormal brain network activity in various brain regions, possibly reflecting the pathological mechanisms of ocular motility disorders in CES.

Altered spontaneous brain activity pattern in patients with late monocular blindness in middle-age using amplitude of low-frequency fluctuation: a resting-state functional MRI study

Objective

Previous reports have demonstrated significant brain activity changes in bilateral blindness, whereas brain activity changes in late monocular blindness (MB) at rest are not well studied. Our study aimed to investigate spontaneous brain activity in patients with late middle-aged MB using the amplitude of low-frequency fluctuation (ALFF) method and their relationship with clinical features.

Methods

A total of 32 patients with MB (25 males and 7 females) and 32 healthy control (HC) subjects (25 males and 7 females), similar in age, sex, and education, were recruited for the study. All subjects were performed with resting-state functional magnetic resonance imaging scanning. The ALFF method was applied to evaluate spontaneous brain activity. The relationships between the ALFF signal values in different brain regions and clinical features in MB patients were investigated using correlation analysis.

Results

Compared with HCs, the MB patients had marked lower ALFF values in the left cerebellum anterior lobe, right parahippocampal gyrus, right cuneus, left precentral gyrus, and left paracentral lobule, but higher ALFF values in the right middle frontal gyrus, left middle frontal gyrus, and left supramarginal gyrus. However, there was no linear correlation between the mean ALFF signal values in brain regions and clinical manifestations in MB patients.

Conclusion

There were abnormal spontaneous activities in many brain regions including vision and vision-related regions, which might indicate the neuropathologic mechanisms of vision loss in the MB patients. Meanwhile, these brain activity changes might be used as a useful clinical indicator for MB.

Altered spontaneous brain activity pattern in patients with high myopia using amplitude of low-frequency fluctuation: a resting-state fMRI study

OBJECTIVE

Many previous reports have demonstrated significant neural anatomy changes in the brain of high myopic (HM) patients, whereas the spontaneous brain activity changes in the HM patients at rest are not well studied. Our objective was to use amplitude of low-frequency fluctuation (ALFF) method to investigate the changes in spontaneous brain activity in HM patients and their relationships with clinical features.

METHODS

A total of 38 patients with HM (17 males and 21 females) and 38 healthy controls (HCs) (17 males and 21 females) closely matched in age, sex, and education underwent resting-state functional magnetic resonance imaging scans. The ALFF method was used to assess local features of spontaneous brain activity. The relationship between the mean ALFF signal values in many brain regions and the clinical features in HM patients was calculated by correlation analysis.

RESULTS

Compared with HCs, the HM patients had significantly lower ALFF in the right inferior and middle temporal gyrus, left middle temporal gyrus, left inferior frontal gyrus/putamen, right inferior frontal gyrus/putamen/insula, right middle frontal gyrus, and right inferior parietal lobule and higher ALFF values in the bilateral midcingulate cortex, left postcentral gyrus, and left precuneus/inferior parietal lobule. However, no relationship was found between the mean ALFF signal values of the different areas and the clinical manifestations in HM.

CONCLUSION

The HM patients were affected with brain dysfunction in many regions, which may indicate the presence of neurobiological changes involving deficits in language understanding and attentional control in HM patients.

Altered spontaneous brain activity patterns in patients with unilateral acute open globe injury using amplitude of low-frequency fluctuation: a functional magnetic resonance imaging study

OBJECTIVE

The aim of this study was to evaluate altered spontaneous brain activities in patients with unilateral acute open globe injury (OGI) using amplitude of low-frequency fluctuation (ALFF) method and its relationship with their clinical manifestations.

PATIENTS AND METHODS

A total of 18 patients with acute OGI (16 males and two females) and 18 healthy controls (HCs, 16 males and two females) closely matched in age, sex, and education were recruited in this study. The ALFF method was used to evaluate the altered spontaneous brain activities. The relationships between the mean ALFF signal values of different brain regions and the clinical features were evaluated by correlation analysis. Acute OGI patients were distinguished from HCs by receiver operating characteristic curve.

RESULTS

Compared with HCs, acute OGI patients had significantly higher ALFF values in the left cuneus, left middle cingulum cortex, and bilateral precuneus. Furthermore, the age of OGI patients showed a negative correlation with the ALFF signal value of the left middle cingulum cortex (r=-0.557, P=0.016) and a negative correlation with the mean ALFF signal value of the bilateral precuneus (r=-0.746, P<0.001). The ALFF signal value of the bilateral precuneus was negatively correlated with the duration of OGI (r=-0.493, P=0.038) and positively correlated with the vision acuity of the injured eye (r=0.583, P=0.011).

CONCLUSION

Acute OGI mainly induces dysfunction in the left cuneus, left middle cingulum cortex, and bilateral precuneus, which may reflect the underlying pathologic mechanisms of abnormal brain activities in OGI patients.

A functional MRI study of altered spontaneous brain activity pattern in patients with congenital comitant strabismus using amplitude of low-frequency fluctuation

OBJECTIVE

The aim of this study was to use amplitude of low-frequency fluctuation (ALFF) to investigate local features of spontaneous brain activity in patients with congenital comitant strabismus and clarify their relationship with emotional and psychosocial problems.

METHODS

A total of 20 patients with congenital comitant strabismus (ten males and ten females), and 20 healthy controls (ten males and ten females) closely matched in age, sex, and education underwent resting-state functional magnetic resonance imaging scans. The ALFF method was used to assess local features of spontaneous brain activity. Congenital comitant strabismus patients were distinguished from healthy controls by receiver operating characteristic curve. Correlation analysis was performed to explore the relationships between the observed mean ALFF signal values of the different areas and the Chinese version of the Hospital Anxiety and Depression Scale.

RESULTS

Compared with healthy controls, patients with congenital comitant strabismus had significantly lower ALFF in the bilateral medialfrontal gyrus and higher values in the bilateral cerebellum posterior lobe and left angular gyrus. In the congenital comitant strabismus group, the Hospital Anxiety and Depression Scale-depression score showed a negative correlation with the ALFF signal values of the bilateral medial frontal gyrus (r=-0.550, P=0.012) and a negative correlation was noted between the mean ALFF signal values of the left angular gyrus and strabismus duration (r=-0.515, P=0.020).

CONCLUSION

Congenital comitant strabismus mainly involves dysfunction in the bilateral medial frontal gyrus, bilateral cerebellum posterior lobe, and left angular gyrus, which may reflect the underlying pathologic mechanism of congenital strabismus.