Amblyopic astigmatism characteristics and surgical outcomes in younger children with severe congenital ptosis after frontalis suspension surgery.

BACKGROUND: To examine the astigmatism characteristics and surgical outcomes in patients with unilateral severe congenital ptosis following frontalis suspension surgery. METHODS: We included 53 congenital ptosis patients who underwent frontalis suspension surgery in Hunan Children's Hospital. Each patient underwent a refractive examination before and after surgery to assess astigmatism. We also evaluated the effects and complications associated with the procedure. RESULTS: Degree of astigmatism in ptotic and fellow eyes was - 1.45 ± 0.59 D and - 0.66 ± 0.51 D before surgery. Ratio of severe astigmatism in ptotic and fellow eyes was 51.3 and 12.8%. The fellow eyes presented with with-the-rule astigmatism (WR; 71.8%) and against-the-rule astigmatism (AR; 20.5%) types, with no cases of oblique astigmatism (OA). Ptotic eyes demonstrated higher frequencies of AR (59.0%) and OA (10.2%) than did fellow eyes. Furthermore, the former showed increased astigmatism, followed by a gradual decrease at the 6-month, before significantly decreasing at the 1-year postoperatively. The ratio of postoperative AR and OA astigmatism cases in ptotic eyes decreased to 35.9 and 7.7% 1 month postoperatively. However, there was a postoperative increase in the WR ratio from 30.8 to 56.4% after 1 month. Kaplan-Meier survival analysis showed a success rate of 81.4% at 6 months and 62.9% at 12 months which was influenced by the following complications: suture reaction, epithelial keratopathy, infection and granuloma, lid lag, and recurrence. CONCLUSION: Monocular congenital ptosis could develop severe astigmatism and higher frequency of AR or OA, early surgery may ameliorate astigmatic amblyopia.

Upper-Limb Amputation Disrupts the Interhemispheric Structural Rather than Functional Connectivity.

Background: Recent neuroimaging studies on upper-limb amputation have revealed the reorganization of bilateral sensorimotor cortex after sensory deprivation, underpinning the assumption of changes in the interhemispheric connections. In the present study, using functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we aim to explore the alterations in the interhemispheric functional and structural connectivity after upper-limb amputation. Methods: Twenty-two upper-limb amputees and 15 age- and sex-matched healthy controls were recruited for MRI scanning. The amputees were further divided into subgroups by amputation side and residual limb pain (RLP). DTI metrics of corpus callosum (CC) subregions and resting-state functional connectivity (FC) between the bilateral sensorimotor cortices were measured for each participant. Linear mixed models were carried out to investigate the relationship of interhemispheric connectivity with the amputation, amputation side, and RLP. Results: Compared with healthy controls, upper-limb amputees showed lower axial diffusivity (AD) in CC subregions II and III. Subgroup analyses showed that the dominant hand amputation induced significant microstructural changes in CC subregion III. In addition, only amputees with RLP showed decreased fractional anisotropy and AD in CC, which was also correlated with the intensity of RLP. No significant changes in interhemispheric FC were found after upper-limb amputation. Conclusion: The present study demonstrated that the interhemispheric structural connectivity rather than FC degenerated after upper-limb amputation, and the degeneration of interhemispheric structural connectivity was shown to be relevant to the amputation side and the intensity of RLP. Impact statement Neuroimaging studies have revealed the functional reorganization of bilateral sensorimotor cortex after amputation, with expanded activation from the intact hemisphere to the deprived hemisphere. Our findings indicated a degeneration of interhemispheric white matter connections in upper-limb amputees, unveiling the underlying structural basis for bilateral functional reorganization after amputation.

Alterations in Brain Structural Connectivity After Unilateral Upper-Limb Amputation.

Previous studies have indicated that amputation induces reorganization of functional brain network. However, the influence of amputation on structural brain network remains unclear. In this study, using diffusion tensor imaging (DTI), we aimed to investigate the alterations in fractional anisotropy (FA) network after unilateral upper-limb amputation. We acquired DTI from twenty-two upper-limb amputees (15 dominant-side and 7 nondominant-side amputees) as well as fifteen healthy controls. Using DTI tractography and graph theoretical approaches, we examined the topological changes in FA network of amputees. Compared with healthy controls, dominant-side amputees showed reduced global mean strength, increased characteristic path length, and decreased nodal strength in the contralateral sensorimotor system and visual areas. In particular, the nodal strength of the contralateral postcentral gyrus was negatively correlated with residual limb usage, representing a use-dependent reorganization. In addition, the nodal strength of the contralateral middle temporal gyrus was positively correlated with the magnitude of phantom limb sensation. Our results suggested a degeneration of FA network after dominant-side upper-limb amputation.

Correlates of Residual Limb Pain: From Residual Limb Length and Usage to Metabolites and Activity in Secondary Somatosensory Cortex.

Most recent studies attribute residual limb pain to peripheral pathological changes of the stump. However, in this paper, we focus on its associations with the residual limb length, usage, as well as the metabolic and functional alterations of the brain. The secondary somatosensory cortex (S2), one important area involved in pain intensity discrimination, was selected as the region of interest. Twenty-two upper-limb amputees were recruited and divided into two groups, i.e., amputees with residual limb pain (9/22) and without residual limb pain (13/22). The residual limb length, usage, as well as the metabolite concentration, resting-state activity and BOLD responses to the tactile stimulation in the contralateral S2, were compared between the two groups and correlated with the pain intensity. The amputees with residual limb pain showed significantly shorter length and less usage of the residual limb than the amputees without residual limb pain, and the pain intensity was significantly negatively correlated with the residual limb length and usage. In addition, the pain intensity was significantly correlated with the tNAA/tCr ratio, resting-state fALFF in the slow-4 band, and BOLD response to the tactile stimulation in the contralateral S2, although there were no significant group differences. Regression analysis suggested that residual limb pain is associated with shorter residual limb length and less residual limb usage.

Exploration of Neural Activity under Cognitive Reappraisal Using Simultaneous EEG-fMRI Data and Kernel Canonical Correlation Analysis.

BACKGROUND: Neural activity under cognitive reappraisal can be more accurately investigated using simultaneous EEG- (electroencephalography) fMRI (functional magnetic resonance imaging) than using EEG or fMRI only. Complementary spatiotemporal information can be found from simultaneous EEG-fMRI data to study brain function. METHOD: An effective EEG-fMRI fusion framework is proposed in this work. EEG-fMRI data is simultaneously sampled on fifteen visually stimulated healthy adult participants. Net-station toolbox and empirical mode decomposition are employed for EEG denoising. Sparse spectral clustering is used to construct fMRI masks that are used to constrain fMRI activated regions. A kernel-based canonical correlation analysis is utilized to fuse nonlinear EEG-fMRI data. RESULTS: The experimental results show a distinct late positive potential (LPP, latency 200-700ms) from the correlated EEG components that are reconstructed from nonlinear EEG-fMRI data. Peak value of LPP under reappraisal state is smaller than that under negative state, however, larger than that under neutral state. For correlated fMRI components, obvious activation can be observed in cerebral regions, e.g., the amygdala, temporal lobe, cingulate gyrus, hippocampus, and frontal lobe. Meanwhile, in these regions, activated intensity under reappraisal state is obviously smaller than that under negative state and larger than that under neutral state. CONCLUSIONS: The proposed EEG-fMRI fusion approach provides an effective way to study the neural activities of cognitive reappraisal with high spatiotemporal resolution. It is also suitable for other neuroimaging technologies using simultaneous EEG-fMRI data.

Directed connectivity of brain default networks in resting state using GCA and motif.

Nowadays, there is a lot of interest in assessing functional interactions between key brain regions. In this paper, Granger causality analysis (GCA) and motif structure are adopted to study directed connectivity of brain default mode networks (DMNs) in resting state. Firstly, the time series of functional magnetic resonance imaging (fMRI) data in resting state were extracted, and the causal relationship values of the nodes representing related brain regions are analyzed in time domain to construct a default network. Then, the network structures were searched from the default networks of controls and patients to determine the fixed connection mode in the networks. The important degree of motif structures in directed connectivity of default networks was judged according to p-value and Z-score. Both node degree and average distance were used to analyze the effect degree an information transfer rate of brain regions in motifs and default networks, and efficiency of the network. Finally, activity and functional connectivity strength of the default brain regions are researched according to the change of energy distributions between the normals and the patients' brain regions. Experimental results demonstrate that, both normal subjects and stroke patients have some corresponding fixed connection mode of three nodes, and the efficiency and power spectrum of the patient's default network is somewhat lower than that of the normal person. In particular, the Right Posterior Cingulate Gyrus (PCG.R) has a larger change in functional connectivity and its activity. The research results verify the feasibility of the application of GCA and motif structure to study the functional connectivity of default networks in resting state.

Functional Connectivity Analysis of Brain Default Mode Networks Using Hamiltonian Path.

The aim of this study is to introduce Hamiltonian path to analyze functional connectivity of brain default mode networks (DMNs). Firstly, the brain DMNs in resting state are constructed with the employment of functional Magnetic Resonance Imaging (fMRI) data. Then, the Dijkstra algorithm is used to calculate the shortest path length of the node which represents each brain region, and the Hamiltonian path of the default network is solved through the improved adaptive ant colony algorithm. Finally, complex network analysis methods are introduced to discuss the node and network properties of brain functional connectivity in both normal subjects and stroke patients. The experimental result demonstrated that there are some significant differences in the properties of the DMNs between stroke patients and normal subjects, especially the length of Hamiltonian path. It also verifies the effectiveness on studying the functional connectivity of the brain DMNs by applying the proposed method of Hamiltonian path.

Functional connectivity analysis of the neural bases of emotion regulation: A comparison of independent component method with density-based k-means clustering method.

Functional magnetic resonance imaging (fMRI) is an important tool in neuroscience for assessing connectivity and interactions between distant areas of the brain. To find and characterize the coherent patterns of brain activity as a means of identifying brain systems for the cognitive reappraisal of the emotion task, both density-based k-means clustering and independent component analysis (ICA) methods can be applied to characterize the interactions between brain regions involved in cognitive reappraisal of emotion. Our results reveal that compared with the ICA method, the density-based k-means clustering method provides a higher sensitivity of polymerization. In addition, it is more sensitive to those relatively weak functional connection regions. Thus, the study concludes that in the process of receiving emotional stimuli, the relatively obvious activation areas are mainly distributed in the frontal lobe, cingulum and near the hypothalamus. Furthermore, density-based k-means clustering method creates a more reliable method for follow-up studies of brain functional connectivity.

Abnormal cerebral functional connectivity in esophageal cancer patients with theory of mind deficits in resting state.

OBJECTIVE: To explore the function of the default mode network (DMN) in the psychopathological mechanisms of theory of mind deficits in patients with an esophageal cancer concomitant with depression in resting the state. SUBJECTS AND METHODS: Twenty-five cases of esophageal cancer with theory of mind deficits (test group) that meet the diagnostic criteria of esophageal cancer and neuropsychological tests, including Beck depression inventory, reading the mind in the eyes, and Faux pas, were included, Another 25 cases of esophageal cancer patients but without theory of mind deficits (control group) were enrolled. Each patient completed a resting-state functional magnetic resonance imaging. RESULTS: The functional connectivity intensities within the cerebral regions in the DMN of all the enrolled patients were analyzed. The results of each group were compared. The functional connectivity of the bilateral prefrontal central region with the precuneus, bilateral posterior cingulate gyrus and bilateral ventral anterior cingulate gyrus in the patients of the test group were all reduced significantly (P < 0.05). In the resting state, the functional connectivity is abnormal in the cerebral regions in the DMN of esophageal cancer patients with theory of mind deficits. CONCLUSIONS: The theory of mind deficits might have an important function in the pathogenesis of esophageal cancer.

P2X7R suppression promotes glioma growth through epidermal growth factor receptor signal pathway.

P2X7 receptor (P2X7R) has been shown to mediate an anticancer effect via apoptosis in different types of cancer. However, whether P2X7R exerts a promoting or suppressive effect on brain glioma is still a controversial issue and its underlying mechanism remains unknown. We showed here that P2X7R suppression exerted a pro-growth effect on glioma through directly promoting cells proliferation and pro-angiogenesis, which was associated with epidermal growth factor receptor (EGFR) signaling. The P2X7R was markedly downregulated by cells exposure to the P2X7R antagonist, brilliant blue G (BBG), moreover, the cells proliferation was enhanced in a dose-dependent manner and the expression of EGFR or p-EGFR protein was significantly upregulated. By constructing C6 cells with reduced expression of P2X7R using shRNA, we also demonstrated strong upregulation in cells proliferation and EGFR/p-EGFR expression. However, this effect of BBG was reversed in the presence of gefitinib or suramin. Magnetic resonance imaging and computed tomography perfusion showed that the BBG or P2X7R shRNA promoted the tumor growth by about 40% and 50%, respectively, and significantly increased angiogenesis. Nissl and Ki-67 staining also confirmed that BBG or P2X7R shRNA notably increased the tumor growth. More importantly, either BBG or P2X7R shRNA could markedly upregulated the expression of EGFR, p-EGFR, HIF-1α and VEGF in glioma cells. In conclusion, P2X7R suppression exerts a promoting effect on glioma growth, which is likely to be related to upregulated EGFR, HIF-1α and VEGF expression. These findings provide important clues to the molecular basis of anticancer effect of targeting purinergic receptors.