Migraine is the most common primary headache clinically, with high disability rate and heavy burden. Functional MRI (fMRI) plays a significant role in the study of migraine. This article reviews the main advances of migraine without aura (MwoA) based on resting-state fMRI in recent years, including the exploration of the mechanism of fMRI in the occurrence and development of MwoA in terms of regional functional activities and functional network connections, as well as the research progress of the potential clinical application of fMRI in aiding diagnosis and assessing treatment effect for MwoA. At last, this article summarizes the current distresses and prospects of fMRI research on MwoA.
Nowadays, an increasing number of researches have shown that epilepsy, as a kind of neural network disease, not only affects the brain region of seizure onset, but also remote regions at which the brain network structures are damaged or dysfunctional. These changes are associated with abnormal network of epilepsy. Resting-state network is closely related to human cognitive function and plays an important role in cognitive process. Cognitive dysfunction, a common comorbidity of epilepsy, has adverse impacts on life quality of patients with epilepsy. The mechanism of cognitive dysfunction in epileptic patients is still incomprehensible, but the change of resting-state brain network may be associated with their cognitive impairment. In order to further understand the changes of resting-state network associated with the cognitive function and explore the brain network mechanism of the occurrence of cognitive dysfunction in patients with epilepsy, we review the related researches in recent years.
Although a great number of studies have investigated the changes of resting-state functional connectivity (rsFC) in patients with mental disorders, such as depression and schizophrenia etc, little is known how stable the changes are, and whether temporal sad or happy mood can modulate the intrinsic rsFC. In our experiments, happy and sad video clips were used to induce temporally happy and sad mood states in 20 healthy young adults. We collected functional magnetic resonance imaging (fMRI) data while participants were watching happy or sad video clips, which were administrated in two consecutive days. Seed-based functional connectivity analyses were conducted using the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), and amygdala as seeds to investigate neural network related to executive function, attention, and emotion. We also investigated the association of the rsFC changes with emotional arousability level to understand individual differences. There is significantly stronger functional connectivity between the left DLPFC and posterior cingulate cortex (PCC) under sad mood than that under happy mood. The increased connectivity strength was positively correlated with subjects' emotional arousability. The increased positive correlation between the left DLPFC and PCC under sad relative to happy mood might reflect an increased processing of negative emotion-relevant stimuli. The easier one was induced by strong negative emotion (higher emotional arousability), the greater the left DLPFC-PCC connectivity was indicated, the greater the instability of the intrinsic rsFC was shown.
Amblyopia is a visual development deficit caused by abnormal visual experience in early life, mainly manifesting as defected visual acuity and binocular visual impairment, which is considered to reflect abnormal development of the brain rather than organic lesions of the eye. Previous studies have reported abnormal spontaneous brain activity in patients with amblyopia. However, the location of abnormal spontaneous activity in patients with amblyopia and the association between abnormal brain function activity and clinical deficits remain unclear. The purpose of this study is to analyze spontaneous brain functional activity abnormalities in patients with amblyopia and their associations with clinical defects using resting-state functional magnetic resonance imaging (fMRI) data. In this study, 31 patients with amblyopia and 31 healthy controls were enrolled for resting-state fMRI scanning. The results showed that spontaneous activity in the right angular gyrus, left posterior cerebellum, and left cingulate gyrus were significantly lower in patients with amblyopia than in controls, and spontaneous activity in the right middle temporal gyrus was significantly higher in patients with amblyopia. In addition, the spontaneous activity of the left cerebellum in patients with amblyopia was negatively associated with the best-corrected visual acuity of the amblyopic eye, and the spontaneous activity of the right middle temporal gyrus was positively associated with the stereoacuity. This study found that adult patients with amblyopia showed abnormal spontaneous activity in the angular gyrus, cerebellum, middle temporal gyrus, and cingulate gyrus. Furthermore, the functional abnormalities in the cerebellum and middle temporal gyrus may be associated with visual acuity defects and stereopsis deficiency in patients with amblyopia. These findings help explain the neural mechanism of amblyopia, thus promoting the improvement of the treatment strategy for amblyopia.
Early diagnosis and accurate stage of liver fibrosis are important for conducting the clinic therapy and assessing the therapeutic outcome. Functional magnetic resonance imaging (fMRI), as a noninvasive and effective method, plays an important role in diagnosis and stage of liver fibrosis. This review focuses on the advances in fMRI evaluation of liver fibrosis.
Objective To investigate the differences in the topology of functional brain networks between populations with good spatial navigation ability and those with poor spatial navigation ability. Methods From September 2020 to September 2021, 100 college students from PLA Army Border and Coastal Defense Academy were selected to test the spatial navigation ability. The 25 students with the highest spatial navigation ability were selected as the GN group, and the 25 with the lowest spatial navigation ability were selected as the PN group, and their resting-state functional MRI and 3D T1-weighted structural image data of the brain were collected. Graph theory analysis was applied to study the topology of the brain network, including global and local topological properties. Results The variations in the clustering coefficient, characteristic path length, and local efficiency between the GN and PN groups were not statistically significant within the threshold range (P>0.05). The brain functional connectivity networks of the GN and PN groups met the standardized clustering coefficient (γ)>1, the standardized characteristic path length (λ)≈1, and the small-world property (σ)>1, being consistent with small-world network property. The areas under curve (AUCs) for global efficiency (0.22±0.01 vs. 0.21±0.01), γ value (0.97±0.18 vs. 0.81±0.18) and σ value (0.75±0.13 vs. 0.64±0.13) of the GN group were higher than those of the PN group, and the differences were statistically significant (P<0.05); the between-group difference in AUC for λ value was not statistically significant (P>0.05). The results of the nodal level analysis showed that the AUCs for nodal clustering coefficients in the left superior frontal gyrus of orbital region (0.29±0.05 vs. 0.23±0.07), the right rectus gyrus (0.29±0.05 vs. 0.23±0.09), the middle left cingulate gyrus and its lateral surround (0.22±0.02 vs. 0.25±0.02), the left inferior occipital gyrus (0.32±0.05 vs. 0.35±0.05), the right cerebellar area 3 (0.24±0.04 vs. 0.26±0.03), and the right cerebellar area 9 (0.22±0.09 vs. 0.13±0.13) were statistically different between the two groups (P<0.05). The differences in AUCs for degree centrality and nodal efficiency between the two groups were not statistically significant (P>0.05). Conclusions Compared with people with good spatial navigation ability, the topological properties of the brains of the ones with poor spatial navigation ability still conformed to the small-world network properties, but the connectivity between brain regions reduces compared with the good spatial navigation ability group, with a tendency to convert to random networks and a reduced or increased nodal clustering coefficient in some brain regions. Differences in functional brain network connectivity exist among people with different spatial navigation abilities.
Objective The ReHo, ALFF, fALFF of resting-state functional magnetic resonance imaging (RS-fMRI) technology were used to study the influencing factors and neural mechanism of cognitive dysfunction in patients with benign epilepsy of childhood with centrotemporal spikes (BECT). Methods Fourteen patients were enrolled (from April 2015 to March 2018) from epilepsy specialist outpatients and Functional Department of Neurosurgery of Tianjin Medical University General Hospital. They underwent the long term VEEG monitoring (one sleep cycle was included at least), the Wechsler Intelligence Scale (China Revised), the head MRI and RS-fMRI examinations. Spike-wave index (SWI), FIQ, VIQ, PIQ scores were calculated. According to full-scale IQ (FIQ), they were divided into two groups: FIQ<90 (scores range from 70 to 89, the average score was 78.3±8.9, 6 cases) and FIQ≥90 (scores range from 90 to 126, the average score was 116.6±12.9, 8 cases). SPSS21.0 statistical software was used to compare the general clinical data and SWI of the two groups, and the correlation between clinical factors and the evaluation results of Wechsler Intelligence Scale was analyzed. The RS-fMRI images were preprocessed and the further data were analysed by two independent samplest-test under the whole brain of regional homogeneity (ReHo), amplitude of low frequency fluctuation (ALFF) and fractional of ALFF (fALFF) methods. The differences of brain activation regions in RS-fMRI between the two groups were observed, and the results of general clinical data, SWI and cognitive function test were compared and analyzed comprehensively. Results The differences of SWI were statistically significant (P<0.05): FIQ<90 group were greater than FIQ≥90 group. The FIQ, VIQ and PIQ of two groups were negatively correlated with SWI (P<0.05). And the FIQ and PIQ were negatively correlated with the total number of seizures (P<0.05). Compared with FIQ≥90 group by two samplet-test based on whole level ReHo, ALFF, fALFF methods, deactivation of brain regions of FIQ<90 group include bilateral precuneus, posterior cingulate and occipital lobe, and enhanced activation of brain regions include left prefrontal cortex, bilateral superior frontal gyrus medial and right precentral gyrus, supplementary motor area, angular gyrus, supramarginal gyrus, middle temporal gyrus, bilateral insular lobe and subcortical gray matter structures. Conclusions Frequent epileptic discharges during slow wave sleep and recurrent clinical episodes were risk factors for cognitive impairment in BECT patients. Repeated clinical seizures and frequent subclinical discharges could cause dysfunction of local brain areas associated with cognition and the default network, resulting in patients with impaired cognitive function.
A great number of studies have demonstrated functional abnormalities in children with attention-deficit/hyperactivity disorder (ADHD), although conflicting results have also been reported. And few studies analyzed homotopic functional connectivity between hemispheres. In this study, resting-state functional magnetic resonance imaging (MRI) data were recorded from 45 medication-naïve ADHD children and 26 healthy controls. The regional homogeneity (ReHo), degree centrality (DC) and voxel-mirrored homotopic connectivity (VMHC) values were compared between the two groups to depict the intrinsic brain activities. We found that ADHD children exhibited significantly lower ReHo and DC values in the right middle frontal gyrus and the two values correlated with each other; moreover, lower VMHC values were found in the bilateral occipital lobes of ADHD children, which was negatively related with anxiety scores of Conners' Parent Rating Scale (CPRS-R) and positively related with completed categories of Wisconsin Card Sorting Test (WCST). Our results might suggest that less spontaneous neuronal activities of the right middle frontal gyrus and the bilateral occipital lobes in ADHD children.