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

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.

Fractional amplitude of low-frequency fluctuation changes of specific cerebral regions in patients with toothache: A functional magnetic resonance imaging study

BACKGROUND

Previous studies have indicated that pain-related diseases can result in significant functional alterations in the brain. However, differences in spontaneous brain activity in toothache (TA) patients remain unclear.

OBJECTIVE

To investigate altered spontaneous brain activity in patients with TA and its underlying mechanisms using the resting-state functional magnetic resonance imaging-fractional amplitude of low-frequency fluctuation (rsfMRI-fALFF) technique.

METHODS

Twelve patients with TA and 12 non-toothache controls (NTCs) (matched for sex, age, and level of education) were enrolled. Spontaneous cerebral activity variations were investigated using the rsfMRI-fALFF technique in all individuals. The mean fALFF values of the TA patients and NTCs were classified using receiver operating characteristic (ROC) curves. The correlations between fALFF signals of distinct brain regions and clinical manifestations of TA patients were evaluated using Pearson's correlation analysis.

RESULTS

TA patients showed lower fALFF values in the left superior frontal gyrus, medial; right superior frontal gyrus, dorsolateral; and left median cingulate and paracingulate gyri (LDCG) than the NTCs. Moreover, ROC curve analysis indicated that the area under the curve of each cerebral region studied had high accuracy. Besides, in the TA group, the visual analog scale score was negatively correlated with fALFF signal values of the LDCG (r = .962, p < .001).

CONCLUSION

Abnormal spontaneous activity was detected in numerous brain regions in patients with TA, which may be valuable for understanding the brain processing mechanism underlying TA. These regional changes in brain activity may serve as effective clinical indicators of TA.

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.

Visually driven functional MRI techniques for characterization of optic neuropathy

Optic neuropathies are conditions that cause disease to the optic nerve, and can result in loss of visual acuity and/or visual field defects. An improved understanding of how these conditions affect the entire visual system is warranted, to better predict and/or restore the visual loss. In this article, we review visually-driven functional magnetic resonance imaging (fMRI) studies of optic neuropathies, including glaucoma and optic neuritis (ON); we also discuss traumatic optic neuropathy (TON). Optic neuropathy-related vision loss results in fMRI deficit within the visual cortex, and is often strongly correlated with clinical severity measures. Using predominantly flickering checkerboard stimuli, glaucoma studies indicated retinotopic-specific cortical alteration with more prominent deficits in advanced than in early glaucoma. Some glaucoma studies indicate a reorganized visual cortex. ON studies have indicated that the impacted cortical areas are briefly hyperactive. For ON, brain deficits are greater in the acute stages of the disease, followed by (near) normalization of responses of the LGN, visual cortex, and the dorsal visual stream, but not the ventral extrastriate cortex. Visually-driven fMRI is sensitive, at least in ON, in discriminating patients from controls, as well as the affected eye from the fellow eye within patients. The use of a greater variety of stimuli beyond checkerboards (e.g., visual motion and object recognition) in recent ON studies is encouraging, and needs to continue to disentangle the results in terms of change over time. Finally, visually-driven fMRI has not yet been applied in TON, although preliminary efforts suggest it may be feasible. Future fMRI studies of optic neuropathies should consider using more complex visual stimuli, and inter-regional analysis methods including functional connectivity. We suggest that a more systematic longitudinal comparison of optic neuropathies with advanced fMRI would provide improved diagnostic and prognostic information.

Voxel-Mirrored Homotopic Connectivity Is Altered in Meibomian Gland Dysfunction Patients That Are Morbidly Obese

Purpose: To investigate the altered functional connectivity (FC) of the cerebral hemispheres in patients with morbid obesity (MO) with meibomian gland dysfunction (MGD) by voxel-mirrored homotopic connectivity (VMHC). Methods: Patients and matched healthy controls (HCs) were recruited, and all subjects underwent functional resonance magnetic imaging (fMRI), and VMHC results were processed statistically to assess the differences in FC in different brain regions between the two groups. We further used ROC curves to evaluate the diagnostic value of these differences. We also used Pearson’s correlation analysis to explore the relationship between changes in VMHC values in specific brain regions, visual acuity, and Mini-Mental State Examination (MMSE) score. Conclusions: Patients with morbid obesity and MGD had abnormal FC in the cerebral hemispheres in several specific brain areas, which were mainly concentrated in pathways related to vision and perception and may correlate to some extent with the clinical presentations of the patients.

Children with strabismus and amblyopia presented abnormal spontaneous brain activities measured through fractional amplitude of low-frequency fluctuation (fALFF)

Purpose

Based on fMRI technology, we explored whether children with strabismus and amblyopia (SA) showed significant change in fractional amplitude of low-frequency fluctuation (fALFF) values in specific brain regions compared with healthy controls and whether this change could point to the clinical manifestations and pathogenesis of children with strabismus to a certain extent.

Methods

We enrolled 23 children with SA and the same number matched healthy controls in the ophthalmology department of the First Affiliated Hospital of Nanchang University, and the whole brain was scanned by rs-fMRI. The fALFF value of each brain area was derived to examine whether there is a statistical difference between the two groups. Meanwhile, the ROC curve was made in a view to evaluate whether this difference proves useful as a diagnostic index. Finally, we analyzed whether changes in the fALFF value of some specific brain regions are related to clinical manifestations.

Results

Compared with HCs, children with SA presented decreased fALFF values in the left temporal pole: the superior temporal gyrus, right middle temporal gyrus, right superior frontal gyrus, and right supplementary motor area. Meanwhile, they also showed higher fALFF values in specific brain areas, which included the left precentral gyrus, left inferior parietal, and left precuneus.

Conclusion

Children with SA showed abnormal fALFF values in different brain regions. Most of these regions were allocated to the visual formation pathway, the eye movement-related pathway, or other visual-related pathways, suggesting the pathological mechanism of the patient.

Brain Activity in Age-Related Macular Degeneration Patients From the Perspective of Regional Homogeneity: A Resting-State Functional Magnetic Resonance Imaging Study

Objective

In this study, the regional homogeneity (ReHo) method was used to investigate levels of cerebral homogeneity in individuals with age-related macular degeneration (AMD), with the aim of exploring whether these measures are associated with clinical characteristics.

Materials and Methods

Patients with AMD and healthy controls attending the First Affiliated Hospital of Nanchang University were invited to participate. Resting state functional magnetic resonance images were recorded in each participant and levels of synchronous neural activity were evaluated using ReHo. Receiver operating characteristic (ROC) curves were used to evaluate the sensitivity and specificity of this method.

Results

Eighteen patients with AMD (9 males and 9 females) and 15 healthy controls (HCs) were recruited. The two groups were approximately matched in age, gender and weight. Compared with controls, the ReHo values were significantly higher in the AMD group at the limbic lobe and parahippocampal gyrus, and were significantly reduced at the cingulate gyrus, superior frontal gyrus, middle frontal gyrus, inferior parietal lobule, and precentral gyrus. Mean ReHo values at the cingulate gyrus and the superior frontal gyrus were negatively correlated with clinical symptoms.

Conclusion

Brain neural homogeneity dysfunction is a manifestation of visual pathways in AMD patients, and may be one of the pathological mechanisms of chronic vision loss, anxiety and depression in AMD patients. In addition, the ReHo data may be useful for early screening for AMD.

Altered spontaneous brain activity patterns in patients with diabetic retinopathy using amplitude of low-frequency fluctuation

BACKGROUND

Diabetes mellitus is a metabolic disorder characterized by prolonged elevation of blood glucose due to various causes. Currently, the relationship between diabetic retinopathy (DR) and altered connectivity of brain function is unclear.

AIM

To investigate the relationship between this brain activity and clinical manifestations and behaviors of DR patients by using the amplitude of low-frequency fluctuation (ALFF) technique.

METHODS

Twenty-four DR patients and 24 healthy controls (HCs) matched for age and gender were enrolled. We measured and recorded average ALFF values of DR patients and HCs and then classified them using receiver operating characteristic (ROC) curves.

RESULTS

ALFF values of both left and right posterior cerebellar lobe and right anterior cingulate gyrus were remarkably higher in the DR patients than in the HCs; however, DR patients had lower values in the bilateral calcarine area. ROC curve analysis of different brain regions demonstrated high accuracy in the area under the curve analysis. There was no significant relationship between mean ALFF values for different regions and clinical presentations in DR patients. Neuronal synchronization abnormalities in some brain regions of DR patients were associated with cognitive and visual disorders.

CONCLUSION

Abnormal spontaneous brain activity was observed in many areas of DR patients’ brains, which may suggest a possible link between clinical manifestations and behaviors in DR patients.

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.

Alternation of brain intrinsic activity in patients with hypertensive retinopathy: a resting-state fMRI study

Objective: To investigate the changes of amplitude of low-frequency fluctuation (ALFF) in brain regions of patients with hypertensive retinopathy by using resting-state functional magnetic resonance imaging (rs-fMRI) and change in the relationship of ALFF value with potential emotional and psychological changes.

Methods: Thirty-one patients with hypertensive retinopathy (HR) (16 men and 15 women) and 31 healthy controls (HCs; 16 men and 15 women) matched for age, sex, and weight were enrolled in the research. The changes in mean ALFF values could reflect brain activity between HR patients and HCs. We used the independent samples t-test to evaluate different demographic and general information between the two groups. Two-sample t-test was used to detect differences of mean ALFF values in the brain region between the two groups using the same software.

Results: The ALFF values in the brain areas of HR and HCs were different. HR patients had lower ALFF value in the left medial superior frontal gyrus and left middle frontal gyrus than the HCs. The higher ALFF values were found in the cerebellum (left inferior and right superior lobes, vermis) and left inferior temporal gyrus of the HR patients than the controls.

Conclusion: Our findings showed fluctuations in ALFF values in the HR patients’ brain regions. ALFF values reflect over or reduced activity in brain regions. Abnormal ALFF values in these brain areas can predict early HR development, preventing the malignant transformation of hypertensive microangiopathy.

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

Background

Previous 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.

Purpose

To investigate the changes in cerebral hemispheric functional connections in patients with SA and their relationship with clinical manifestations using the VMHC method.

Material and methods

In 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.

Results

Compared 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.

Conclusion

SA subjects showed abnormal brain interhemispheric functional connectivity in visual pathways, which might give some instructive information for understanding the neurological mechanisms of SA patients.

Regional brain changes in patients with diabetic optic neuropathy: a resting-state functional magnetic resonance imaging study

Background

To evaluate functional connection density (FCD) in patients with diabetic optic neuropathy (DON) using the resting functional connectivity (FC) method, and to determine the abnormal areas of brain activity.

Methods

Patients with DON (n=22; 10 male, 12 female) and healthy controls (HCs; n=22; 10 male, 12 female) were included in the study. The basic characteristics of the groups were matched. Functional magnetic resonance imaging (fMRI) was conducted with participants at rest, and long- and short-range FCD (long FCD and IFCD, respectively) were measured. Receiver operating characteristic (ROC) curve analysis was also conducted to determine whether DON and HC participants could be distinguished using fMRI indicators.

Results

Compared with HCs, the long FCD values of the left lingual gyrus, right lingual gyrus, right fusiform gyrus, and medial and lateral cingulate gyri were decreased in patients with DON. Further, the IFCD values of the left superior temporal gyrus, left inferior temporal gyrus, right inferior temporal gyrus, left cerebellar area 8, and right cerebellar Crus2 area were higher in patients with DON than in the HCs.

Conclusions

DON is associated with abnormal spontaneous brain activity. Our findings contribute to elucidating the mechanisms underlying the neuropathology of DON, and provide direction for further clinical research.

Altered brain network centrality in middle-aged patients with retinitis pigmentosa: A resting-state functional magnetic resonance imaging study

OBJECTIVE

The purpose of this study is to explore the underlying functional network brain activity changes of patients in middle-aged with retinitis pigmentosa (RP) and the relationships with clinical features such as depression scale and visual functioning using voxel-wise degree centrality (DC) method.

METHODS

We included 16 patients with RP (11 men, 5 women) and 16 healthy controls (HCs; 11 men, 5 women). Participants were matched in terms of age, weight, gender and handedness (age and weight between the two groups were compared using independent sample t-tests, gender and handedness were compared using chi-square test). We use the voxel-wise DC method to assess spontaneous brain activity. Receiver operating characteristic (ROC) curve analysis was performed to distinguish between RP patients and HCs. Correlation analysis was used to examine the relationships between mean DC values in various brain regions and clinical features (such as depression scale and visual functioning) in RP patients.

RESULTS

Compared with HCs, the DC values of patients with RP were reduced in the right medial frontal gyrus, bilateral cuneus, bilateral precuneus, and bilateral superior frontal gyrus, and increased in the right cerebellum posterior lobe, left inferior temporal gyrus, and right fusiform gyrus. The mean DC values in the bilateral cuneus negatively correlated with the depression scale, and those in the bilateral precuneus positively correlated with the Visual Functioning Questionnaire-25.

CONCLUSIONS

Middle-aged patients with RP exhibit abnormal brain network activity in various brain regions, and this may underlie the pathological mechanism of RP.

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.

Altered spontaneous brain activity patterns in patients with retinal vein occlusion indicated by the amplitude of low-frequency fluctuation: A functional magnetic resonance imaging study

The aim of the present study was to explore the amplitude of low-frequency fluctuations (ALFF; a measurement of spontaneous brain activity) in different brain regions of patients with retinal vein occlusion (RVO) and its association with vision changes measurements. A total of 24 RVO patients (12 males and 12 females) and 24 healthy controls (HCs, 12 males and 12 females) were recruited, and they were closely matched regarding age, gender and education level (classified according to nine-year compulsory education in China and higher education, all including primary school, junior school, high school and university). ALFF values of different brain regions were gathered and analyzed, and statistical analysis software was used to explore the correlations between the average ALFF signals and clinical features. The ability of ALFF values to distinguish between subjects with RVO and HCs was analyzed by receiver operating characteristic (ROC) curves. The results indicated that the subjects from the RVO group had higher ALFF values than the HCs in the posterior lobe of the left cerebellum, inferior temporal gyrus, cerebellar anterior lobe, right cerebellum posterior/anterior lobe, and lower ALFF values in the medial frontal gyrus, right precuneus, left middle frontal gyrus, right angular gyrus and right superior frontal gyrus. The ROC curve analysis of each brain region indicated that the accuracy of the area under the ROC curves regarding the prediction of RVO was excellent. The best-corrected visual acuity (VA) in the left eye was positively correlated with the ALFF value of the right precuneus (r=0.767, P=0.004) and the best-corrected VA in the right eye was positively correlated with the ALFF value of the left middle frontal gyrus (r=0.935, P<0.001). The central subfield retinal thickness in the left eye was negatively correlated with the ALFF value of the right precuneus (r=−0.895; P<0.001). The duration of RVO in the right eye was positively correlated with the ALFF value of the left middle frontal gyrus (r=0.868; P<0.001). In conclusion, the present results indicate that RVO is associated with dysfunction of diverse brain regions, including language- and movement-associated areas, which may reflect the underlying pathogenic mechanisms of RVO (trial registry no. CDYFY-LL-2017025).

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.

Application of amplitude of low‑frequency fluctuation to altered spontaneous neuronal activity in classical trigeminal neuralgia patients: A resting‑state functional MRI study

Recent studies have reported structural and functional abnormalities in multiple brain regions of classical trigeminal neuralgia (CTN) patients. Differences in spontaneous neuronal activity between CTN patients and healthy subjects, however, remain unknown. The aim of the present study was to investigate alterations in brain activity by application of amplitude of low frequency fluctuation (ALFF), thus analyzing the correlation between durations of spontaneous pain intensity and ALFF values in CTN patients. A total of 28 CTN patients (male, n=12; female, n=16) and 28 healthy controls (HCs; male, n=12; female, n=16) matched for age and sex were enrolled. All subjects underwent resting‑state functional magnetic resonance imaging and changes in spontaneous brain activity were investigated using an ALFF method. Receiver operating characteristic (ROC) curve analysis was applied to differentiate ALFF values of CTN patients from HCs. Altered ALFF values and clinical manifestations were evaluated using Pearson's correlation analysis. ALFF values of the bilateral inferior cerebellum, bilateral fusiform gyrus, right precentral gyrus, left inferior temporal gyrus, right superior cerebellum, left inferior occipital gyrus and right superior occipital gyrus were significantly higher in CTN patients when compared to HCs. ROC curve analysis of each brain revealed a near‑perfect AUC accuracy. Pearson's correlation analysis revealed the visual analog scale of the right eye to be positively correlated with both left inferior temporal and occipital gyral findings, while episode duration likewise was positively associated with left inferior temporal gyral findings. CTN patients exhibited abnormal spontaneous activity in multiple brain regions closely related to pain regulation and perception, while VAS and CTN episode duration were positively correlated with ALFF signal values in some brain regions. The present findings provide further insight into the pathological mechanisms underlying CTN.

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.

Reduction in interhemispheric functional connectivity in the dorsal visual pathway in unilateral acute open globe injury patients: a resting-state fMRI study

This study investigated the changes in interhemispheric functional connectivity (FC) of the whole brain in open globe injury (OGI) patients, using voxel-mirrored homotopic connectivity (VMHC), and their relationships with clinical features. Totally, 16 male and 2 female acute OGI patients and 18 sex, age, and education-matched healthy volunteers were enrolled in the study. All subjects were scanned through functional magnetic resonance imaging (fMRI). Receiver operating characteristic (ROC) curves analyses had been used to identify the VMHC in these brain areas could be used as biomarkers to distinguish OGI and from healthy control (HC). The mean VMHC values in multiple brain areas and clinical OGI manifestations were evaluated with a Pearson correlation analysis. OGI patients had significantly decreased VMHC in the bilateral calcarine/lingual/cuneus (BA18, 19, 30) and middle occipital gyrus (BA18, 19). The OGI patients had abnormal interhemispheric FC in the dorsal visual pathway, which may represent the pathophysiological mechanism that underlies acute vision loss after OGI.

Network centrality in patients with acute unilateral open globe injury: A voxel‑wise degree centrality study

The present study aimed to investigate functional networks underlying brain‑activity alterations in patients with acute unilateral open globe injury (OGI) and associations with their clinical features using the voxel‑wise degree centrality (DC) method. In total, 18 patients with acute OGI (16 males and 2 females), and 18 healthy subjects (16 males and 2 females), closely matched in age, sex and education, participated in the present study. Each subject underwent a resting‑state functional magnetic resonance imaging scan. The DC method was used to assess local features of spontaneous brain activity. Receiver operating characteristic curve analysis was used to distinguish OGIs from healthy controls (HCs). Correlation analysis was used to examine the association between the observed mean DC values of different brain areas and behavioral performance. Compared with HCs, patients with acute unilateral OGI had significantly increased DC values in the bilateral primary visual cortex (V1/V2) and left precuneus (PCUN), and significantly decreased DC values in the right insula, left insula, right inferior parietal lobule (IPL)/supramarginal gyrus (SMG), IPL/SMG, right supplementary motor area and right postcentral gyrus. Additionally, in the acute OGI group, it was observed that the duration of OGI was negatively correlated with the DC signal value of the bilateral V1/V2 (r=‑0.581; P=0.011) and left PCUN (r=‑0.508; P=0.031). Acute OGI led to brain functional network dysfunction in a number of brain regions, which may indicate impairment of the visual cortex and other vision‑associated brain regions in OGI.

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.