Dynamic functional connectivity (FC) studies have shown that motor recovery after stroke was associated with functional reorganization of brain networks. However, most previous studies have focused on interregional variability rather than the temporal variability (TV) of specific regions or networks. TV quantifies the dynamic reconfiguration of a region’s or network’s functional connectivity profile over time and reflects neural flexibility. This study investigated functional reorganization in chronic subcortical stroke using TV of brain networks derived from resting-state fMRI. Thirty-three patients with left subcortical stroke (LSS), thirty with right subcortical stroke (RSS), and fifty-six age- and sex-matched healthy controls (HCs) were enrolled. Stroke patients underwent resting-state fMRI and Upper Extremity Fugl-Meyer Assessment (UE-FMA) at two time points. TV was computed to characterize dynamic functional connectivity at regional, intra-network, and inter-network levels. Group differences were assessed using one-way ANCOVA with post hoc tests. Linear regression was used to examine associations between TV and motor outcomes. The false discovery rate was used to multiple comparisons correction. Compared with HCs, both LSS and RSS showed significantly reduced TV in the right frontal-cingulate regions, the somatomotor hand network (SSH), and the connections between SSH and higher-order cognitive networks (all p < 0.05, |Cohen’s d| > 0.49). Increased TV was observed in the left postcentral gyrus, inferior frontal gyrus, cerebellar network (CEN), and somatomotor mouth network (all p < 0.05, |Cohen’s d| > 0.48). Relative to LSS, RSS exhibited additional TV reductions in the right middle occipital gyrus, orbital middle frontal gyrus, default mode network (DMN), and interactions among higher-order cognitive networks (all p < 0.05, |Cohen’s d| > 0.65). Notably, TV in the right opercular inferior frontal gyrus (IFGoperc) (β = 102.69, adjusted p = 6.4 × 10− 5) and CEN (β = 27.87, adjusted p = 0.011) at the first observation positively correlated with UE-FMA scores at follow-up, with effects modulated by lesion laterality. TV captures multiscale functional reorganization in chronic subcortical stroke involving motor, cognitive, and sensory networks. TV of the right IFGoperc showed potential as a neuroimaging biomarker for predicting post-stroke motor recovery.

BACKGROUND:The contralesional dorsal premotor cortex has been proposed as a potential neuromodulatory target for patients with severe upper limb impairment due to subacute ischemic stroke. This proof-of-concept study aimed to compare behavioral outcomes and resting-state neuroimaging findings between high-frequency repetitive transcranial magnetic stimulation (rTMS) over the contralesional dorsal premotor cortex and guideline-supported low-frequency stimulation over the contralesional primary motor cortex. METHODS:In this randomized trial, 46 patients with severe upper limb impairment in the subacute stage after ischemic stroke were randomly assigned to receive either high-frequency rTMS over the contralesional dorsal premotor cortex or low-frequency rTMS over the contralesional primary motor cortex. Low-frequency stimulation over the contralesional primary motor cortex served as an evidence-supported active comparator for poststroke upper limb motor recovery. Stimulation was administered five times per week for two weeks using magnetic resonance imaging-guided neuronavigation. All participants received concurrent standard rehabilitation therapy. The primary outcome was the Fugl-Meyer Assessment for Upper Extremity. Secondary outcomes included the Arm Subscore of the Motricity Index, the Hong Kong version of the Functional Test for the Hemiplegic Upper Extremity, the Modified Barthel Index, and resting-state functional magnetic resonance imaging-derived degree centrality. RESULTS:Both groups showed significant improvements in the primary and secondary behavioral measures (p < 0.01), with no significant between-group differences in the magnitude of change (p > 0.05). In neuroimaging analyses, patients receiving high-frequency rTMS over the contralesional dorsal premotor cortex showed significantly greater degree centrality changes in the ipsilesional middle occipital gyrus, contralesional medial superior frontal gyrus, and contralesional middle frontal gyrus than those receiving low-frequency rTMS over the contralesional primary motor cortex (p < 0.05). Within the high-frequency stimulation group, degree centrality changes in the ipsilesional middle occipital gyrus were positively correlated with improvements in the Fugl-Meyer Assessment for Upper Extremity (r = 0.619, false discovery rate-corrected p = 0.018). CONCLUSIONS:High-frequency rTMS over the contralesional dorsal premotor cortex produced behavioral improvements comparable to guideline-supported low-frequency rTMS over the contralesional primary motor cortex, without establishing superiority or formal non-inferiority. Exploratory neuroimaging analyses showed greater degree centrality changes in the ipsilesional middle occipital gyrus after high-frequency premotor stimulation, and these changes correlated with upper-limb motor improvement. These findings support further investigation of contralesional dorsal premotor cortex-targeted high-frequency rTMS for severe subacute post-stroke upper limb impairment. REGISTRATION:URL: http://www.chictr.org.cn; Unique identifier: ChiCTR2000038049.

Ex-vivo MRI offers invaluable insights into the complexity of the human brain, enabling high-resolution anatomical delineation and integration with histopathology, and thus, contributes to both basic and clinical studies on normal and pathological brains. However, ex-vivo MRI is challenging in sample preparation, acquisition, and data analysis, and existing ex-vivo MRI datasets are often single image modality and lack of ethnic diversity. In our study, we aimed to address these limitations by constructing a comprehensive multimodal MRI database acquired from six ex-vivo Chinese human brains. This database included structural MRI, high-angular resolution diffusion MRI, quantitative susceptibility mapping, and quantitative T1 and T2 maps, which enabled multifaceted depiction of brain microstructure and connectivity. Furthermore, we generated population-averaged multimodal templates and the segmentation labels to facilitate analysis of ex-vivo brain MRI. This public database offers a collection of high-resolution and multi-parametric ex-vivo human brain MRI and filled the gap of lacking Asian brain samples in existing databases.

The structural and functional characteristics of hippocampal subfields have been extensively studied in dementia, with findings indicating stronger associations with cognitive performance than those observed in the whole hippocampus (HP). However, the impact of post-stroke dementia (PSD) on the structural and functional connectivity between hippocampal subfields and cortical regions remains unclear. The objective of this study is to examine alterations in the functional and structural connectivity between hippocampal subfields and cortical regions in PSD. We collected resting-state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) data from 24 PSD patients, 36 post-stroke non-demented (PSND) patients, and 21 normal controls (NC). These data were used to estimate fractional amplitude of low-frequency fluctuations (fALFF), fractional anisotropy (FA), and diffusivity maps in the hippocampal subfields. Additionally, we constructed functional and structural connectivity matrices between hippocampal subfields and cortical regions for each participant, highlighting group-specific connectivity alterations. Statistical analyses were conducted using a linear mixed model to compare group differences and assess the relationship between MRI measures and clinical evaluations. Our results revealed distinct PSD-related changes in functional connectivity, particularly with the temporal-occipital cortex, within hippocampal subfields compared to the whole HP. Notably, different subfields contributed differently to connectivity changes within the entire HP. Furthermore, we identified positive correlations between diffusivity in the bilateral hippocampal tails and illness duration in PSND patients, which were not observed in PSD. These findings highlight the significant impact of PSD on hippocampal subfields, with subfield analysis offering new insights into the underlying mechanisms of PSD.

IntroductionThis study aimed to develop an automated approach for assessing upper limb (UL) motor impairment severity in stroke patients using a deep learning framework applied to resting-state functional magnetic resonance imaging (rs-fMRI).MethodsDynamic functional connectivity (dFC) was computed with the ipsilesional primary motor cortex (M1) as a seed and extracted from rs-fMRI data of 69 stroke patients. These dFC features were used to train a three-dimensional convolutional neural network (3D-CNN) for automatic classification of UL motor impairment severity. Patients were divided into two groups according to UL Fugl-Meyer Assessment (UL-FMA) scores: mild-to-moderate impairment (UL-FMA > 20; n = 29, maximum = 66) and severe impairment (0 ≤ UL-FMA ≤ 20; n = 40). UL-FMA scores served as labels for supervised learning.ResultsThe model achieved a balanced accuracy of 99.8% ± 0.2%, with a specificity of 99.9% ± 0.2% and a sensitivity of 99.7% ± 0.3%. Several brain regions—including the angular gyrus, medial orbitofrontal cortex, dorsolateral superior frontal gyrus, superior parietal lobule, supplementary motor area, thalamus, cerebellum, and middle temporal gyrus—were linked to UL motor impairment severity.DiscussionThese findings demonstrate that a 3D deep learning framework based on dFC features from rs-fMRI enables highly accurate and objective classification of UL motor impairment in stroke patients. This approach may provide a valuable alternative to manual UL-FMA scoring, particularly in clinical settings with limited access to experienced evaluators.

The laminar-specific distributions of Aβ and Tau deposition in the neocortex of Alzheimer's disease (AD) have been established. However, direct evidence about the effect of AD pathology on cortical microstructure is lacking in human studies. We performed high-resolution T2-weighted and diffusion-weighted MRI (dMRI) on 15 ex vivo whole-hemisphere specimens, including eight cases with low AD neuropathologic change, three cases with primary age-related tauopathy (PART), and four healthy controls (HCs). Using the diffusion tensor model, we evaluated microstructure patterns in six layers of gray matter cortex and performed MRI-histology correlation analysis across cortical layers. Aβ-positive cases exhibited higher diffusivity than Aβ-negative cases (PART and HC) in selected cortical regions, particularly in the inferior frontal cortex. Both Aβ/Tau depositions and dMRI-based microstructural markers demonstrated distinct cortical layer-dependent and region-specific patterns. A significant positive correlation was observed between increased diffusivity and Aβ burden across six cortical layers but not with Tau burden. Furthermore, the mean diffusivity in layer V of the inferior frontal cortex significantly increased with the Amyloid stage. Our findings demonstrate a layer-dependent effect of Aβ pathology on cortical microstructure of the human brain, which may be used to serve as a marker of low AD neuropathologic change.

Multi-echo gradient-echo (mGRE) is an important method to quantify myelin water fraction (MWF) of the human brain, but the results may depend on field strength given the difference in T2*. This study performed mGRE-based MWF on ex vivo human brain at high resolution at both 3T and 7T. We found MWF-derived from 7T showed higher measurements with lager standard deviations compared to those 3T, and the 3T and 7T results showed moderate agreement. These findings indicated the MWF mapping result was field-strength dependent and further validations were needed to support their reliability.

PURPOSE:To compare the myelin water fraction (MWF) measurements between 3 T and 7 T and between in vivo and ex vivo human brains, and to investigate the relationship between multi-echo gradient-echo (mGRE)-based 3D MWF and myelin content using histological staining, which has not been validated in the human brain. METHODS:In this study, we performed 3D mGRE-based MWF measurements on five ex vivo human brain hemispheres and five healthy volunteers at 3 T and 7 T with 1 mm isotropic resolution. The data were fitted with the T 2 * $$ {\mathrm{T}}_2^{\ast } $$ based on a three compartment complex-valued model to estimate MWF. We obtained myelin basic protein (MBP) staining from two tissue blocks and co-registered the MWF map and histology image for voxel-wise correlation between the two. RESULTS:The MWF values measured from 7 T were overall higher than 7 T, but data between the two field strength demonstrated high correlations both in vivo (r = 0.88) and ex vivo (r = 0.83) across 19 white matter regions. Moreover, the MWF measurements showed a good agreement between in vivo and ex vivo assessments at 3 T (r = 0.61) and 7 T (r = 0.54). Based on MBP staining, the MWF values exhibited strong positive correlations with myelin content on both 3 T (r = 0.68 and r = 0.78 for the two tissue blocks) and 7 T (r = 0.64 and r = 0.82 for the two tissue blocks). CONCLUSION:The findings demonstrated that the mGRE-based MWF mapping can be used to quantify myelin content in the human brain, despite the field-strength dependency of the measurements.

目的 探究单侧皮质下脑卒中半球间同位脑区经胼胝体结构连接变化与临床运动功能障碍的关系.材料与方法 招募34例单侧皮质下脑卒中患者和43例健康人并采集磁共振弥散张量成像数据.利用高分辨经胼胝体纤维束模板(trancallosal tract template,TCATT)计算并比较卒中组与健康对照组通往半球间同位脑区(包括感觉运动区、前额叶、顶叶、颞叶和枕叶)的32条经胼胝体神经纤维束的各向异性分数(fractional anisotropy,FA)的差异,进一步与皮质脊髓束(corticospinal tract,CST)的FA比率(FA ratio,rFA)和上肢运动功能评分(fugl-meyer assessment of upper extremity,FM-UE)进行相关性分析.结果 与健康对照组相比,卒中组半球间同位脑区的32条经胼胝体神经纤维束在中矢状面区域的FA值均降低,其中差异有统计学意义的有29条(不包括直回、中央旁小叶和内侧眶回的同位脑区经胼胝体纤维束).这29条经胼胝体神经纤维束在中矢状面区域的FA值与rFA(CST)、FM-UE均存在显著正相关(P<0.05).卒中组rFA(CST)与FM-UE评分亦呈显著正相关(r=0.596,P=0.0004).结论 本研究证实皮质下脑卒中的胼胝体微结构受损与病灶同侧CST损伤密切相关.继发性跨半球结构连接损伤对皮质下脑卒中运动功能障碍具有同样重要的影响.

Background and ObjectiveTo investigate the pathway-specific correspondence between structural and functional changes resulting from focal subcortical stroke and their causal influence on clinical symptom.MethodsIn this retrospective, cross-sectional study, we mainly focused on patients with unilateral subcortical chronic stroke with moderate-severe motor impairment assessed by Fugl-Meyer Assessment (upper extremity) and healthy controls. All participants underwent both resting-state fMRI and diffusion tensor imaging. To parse the pathway-specific structure-function covariation, we performed association analyses between the fine-grained corticospinal tracts (CSTs) originating from 6 subareas of the sensorimotor cortex and functional connectivity (FC) of the corresponding subarea, along with the refined corpus callosum (CC) sections and interhemispheric FC. A mediation analysis with FC as the mediator was used to further assess the pathway-specific effects of structural damage on motor impairment.ResultsThirty-five patients (mean age 52.7 ± 10.2 years, 27 men) and 43 healthy controls (mean age 56.2 ± 9.3 years, 21 men) were enrolled. Among the 6 CSTs, we identified 9 structurally and functionally covaried pathways, originating from the ipsilesional primary motor area (M1), dorsal premotor area (PMd), and primary somatosensory cortex (p < 0.05, corrected). FC for the bilateral M1, PMd, and ventral premotor cortex covaried with secondary degeneration of the corresponding CC sections (p < 0.05, corrected). Moreover, these covarying structures and functions were significantly correlated with the Fugl-Meyer Assessment (upper extremity) scores (p < 0.05, uncorrected). In particular, FC between the ipsilesional PMd and contralesional cerebellum (β = −0.141, p < 0.05, CI = [−0.319 to −0.015]) and interhemispheric FC of the PMd (β = 0.169, p < 0.05, CI = [0.015–0.391]) showed significant mediation effects in the prediction of motor impairment with structural damage of the CST and CC.DiscussionsThis study reveals causal influence of structural and functional pathways on motor impairment after subcortical stroke and provides a promising way to investigate pathway-specific structure-function coupling. Clinically, our findings may offer a circuit-based evidence for the PMd as a critical neuromodulation target in more impaired patients with stroke and also suggest the cerebellum as a potential target.

The present study aimed to evaluate magnetic resonance (MR) thermometry using proton resonance frequency shift (PRFS) during laser-induced thermotherapy (LITT), and to compare the results of using different sequences at a field strength of 7-Tesla to identify the optimal for use in ablation so that the surrounding healthy tissues may be protected from damaging in real time. LITT was applied to agarose gel phantoms and ex-vivo porcine brains. We reconstructed both magnitude and phase images to perform MR thermometry based on PRFS methods. We tested four different sequences: a gradient-echo (GRE), a segmented gradient-echo echoplanar imaging (EPI-GRE), a fast-low angle shot (FLASH), and a true fast imaging with steady precession (TRUFI). Temperature was monitored and verified using a fiber-optic thermometry device. All sequences showed good linear correlations (R = 0.97–0.99) between the measured temperature and the calculated MR-thermometry measurements. The phantom/porcine brain experiments revealed the temperature precisions at 1.53/0.69 °C (GRE), 0.61/0.43 °C (EPI-GRE), 1.64/1.32 °C (FLASH), and 0.58/1.52 °C (TRUFI), respectively. Furthermore, we performed a Bland–Altman analysis and the temperature accuracies were found to be − 1.32/− 0.60 °C (GRE), 0.42/− 0.33 °C (EPI-GRE), − 1.28/− 0.98 °C (FLASH), and 0.14/0.46 °C (TRUFI) in the phantom/porcine brain experiments, respectively. Our experiments recommend that EPI-GRE sequence be the best of the all sequences for MR temperature imaging with PRFS in the LITT on 7 T magnetic resonance imaging (MRI) systems because of its relatively higher precision and accuracy.

Background:Myelin water imaging (MWI) is powerful and important for studying and diagnosing neurological and psychiatric diseases. In particular, myelin water fraction (MWF) is derived from MWI data for quantifying myelination. However, MWF estimation is typically sensitive to noise. Improving the accuracy of MWF estimation based on WMI data acquired using a magnetic resonance (MR) multiple gradient recalled echo (mGRE) imaging sequence is desired.Methods:The proposed method employs a recently introduced the multi-channel denoising convolutional neural networks (MCDnCNN). Five different MCDnCNN models, denoted as Delevel1, Delevel2, Delevel3, Delevel4 and DelevelMix corresponding to five noise levels (Level1, Level2, Level3, Level4 and LevelMix), were trained using the data of the first echo of the mGRE brain images acquired from 15 healthy human subjects. Using simulated noisy data that employed a hollow cylinder model, we first evaluated the improvement in estimating MWF based on data denoised by the five different MCDnCNNs, by comparing the MWF maps calculated from the denoised data with ground truth. Next, we again evaluated the improvement using real-world in vivo datasets of 11 human participants acquired using the mGRE sequence. The datasets were first denoised by five different MCDnCNNs (Delevel1, 2, 3, 4 and DelevelMix), and subsequently their MWF maps were calculated and compared with the MWF maps directly calculated from the raw mGRE images without being denoised.Results:Experiments using the simulation data denoised by the appropriate MCDnCNN models showed that the standard deviation (SD) of the absolute error (AE) of the derived MWF results was significantly reduced (maximal reduction =15.5%, Level3 simulated noisy data, orientation angle =0, all the five MCDnCNN models). In the test using in vivo data, estimating MWF based on data particularly denoised by the appropriate MCDnCNN models was found to be the best, compared to otherwise not using the appropriate models. The results demonstrated that the appropriate MCDnCNN models may permit high-quality MWF mapping, i.e., substantial reduction of random variation in estimating MWF-maps while preserving accuracy and structural details.Conclusions:Appropriate MCDnCNN models as proposed may improve both the accuracy and precision in estimating MWF maps, thereby making it a more clinically feasible alternative.

Using magnetic resonance diffusion tensor imaging data from 45 patients with major depressive disorder (MDD) and 41 healthy controls (HCs), network indices based on a 246-region Brainnetcome Atlas were investigated in the two groups, and in the MDD subgroups that were subgrouped based on their duration of the disease. Correlation between the network indices and the duration of illness was also examined. Differences were observed between the MDDS subgroup (short disease duration) and the HC group, but not between the MDD and HC groups. Compared with the HCs, the clustering coefficient (CC) values of MDDS were higher in precentral gyrus, and caudal lingual gyrus; the CC of MDDL subgroup (long disease duration) was higher in postcentral gyrus and dorsal granular insula in the right hemisphere. Network resilience analyses showed that the MDDS group was higher than the HC group, representing relatively more randomized networks in the diseased brains. The correlation analyses showed that the caudal lingual gyrus in the right hemisphere and the rostral lingual gyrus in the left hemisphere were particularly correlated with disease duration. The analyses showed that duration of the illness appears to have an impact on the networking patterns. Networking abnormalities in MDD patients could be blurred or hidden by the heterogeneity of the MDD clinical subgroups. Brain plasticity may introduce a recovery effect to the abnormal network patterns seen in patients with a relative short term of the illness, as the abnormalities may disappear in MDDL .

目的 运用静息态功能磁共振成像(resting-state function magnetic resonance imaging,rs-fMRI)探究太极拳零基础者在太极拳不同学习阶段的脑功能活动的局部一致性(regional homogeneity,ReHo)变化.材料与方法 采用被试内设计,对18名太极拳零基础被试在太极拳学习初期(2周)和学习14周进行同样内容的静息态功能磁共振成像检查.然后分别计算前后两个不同时间点被试的全脑ReHo值并进行相关统计学分析.结果 与太极拳学习2周比较,太极拳学习14周被试右侧梭状回的ReHo值显著增高,而右侧小脑和左侧顶上小叶的ReHo值显著降低(AlphaSim校正P<0.05);其中右侧小脑的ReHo的变化值与太极拳技能评分的变化值呈显著负相关(r=-0.507,P=0.032).多元回归分析发现,太极拳学习2周被试的右侧颞中回、右侧前扣带回的ReHo值与太极拳技能评分的变化量呈显著正相关(r=0.908、0.818,P<0.01),而左侧枕下回及右侧颞上回的ReHo值与太极拳技能评分的变化量呈显著负相关(r=-0.474,P<0.05;r=-0.824,P<0.01).结论 研究结果 表明,随着太极拳学习技能水平的提高,被试的静息态功能活动局部一致性变化,反映了相关脑区可塑性.另外,太极拳学习初期某些脑区的ReHo值对太极拳技能学习效果有一定的潜在预测作用.

目的运用磁共振扩散张量成像(diffusion tensor imaging,DTI)探究脑卒中皮质脊髓束(corticospinal tract,CST)扩散定量指标与运动功能的关系.材料与方法采集37例单侧皮质下脑卒中患者和30例健康被试的DTI数据,运用概率性纤维束成像追踪出健康被试的CST,获得健康对照组CST模板.基于健康对照组的CST模板测量两组被试双侧CST的各向异性分数(fractional anisotropy,FA)和平均扩散率(mean diffusivity,MD),进一步计算两组被试FA比率(FA ratio,rFA)、FA不对称性(FA asymmetry,FAasy)、MD比率(MD ratio,rMD)和MD不对称性(MD asymmetry,MDasy),用这六个扩散参数相关指标来评估脑卒中患者CST完整性损伤,并与患者"手+腕"及上肢运动功能评分(Fugl-Meyer Assessment,FMA)作相关性分析.结果与健康对照组相比,卒中组病灶同侧CST的FA、rFA显著降低(分别为t=-15.775,t=-11.111,P<0.001),FAasy显著增高(t=9.473,P<0.001);而MD、rMD显著增高(分别为t=9.553,t=7.733,P<0.001),MDasy显著降低(t=-8.941,P<0.001);病灶对侧CST的FA和MD均无显著变化(P>0.05).患者病程及病灶大小与各扩散指标间均无显著相关关系(P>0.05).卒中组病灶同侧CST的FA和rFA与"手+腕"及上肢FMA呈显著正相关(分别为r=0.342,P=0.038;r=0.479,P=0.003;r=0.343,P=0.038;r=0.482,P=0.003),FAasy与"手+腕"及上肢FMA呈显著负相关(分别为r=-0.353,P=0.032;r=-0.490,P=0.002).分步回归分析进一步发现,相较于病灶同侧CST的FA和rFA,FAasy与"手+腕"和上肢运动功能评分更加相关(分别为Beta=-0.353,P=0.032;Beta=-0.490,P=0.002).结论基于健康对照组CST模板测得的FA相关指标能反映CST结构完整性.FAasy与"手+腕"及上肢运动功能评分密切相关,或许可作为评估脑卒中患者手腕部和上肢运动功能障碍的重要参考指标.

目的 探讨皮质下脑卒中后手运动相关脑区正负网络连接的变化及与运动功能障碍的关系.材料与方法 对18例单侧皮层下脑卒中患者和18名性别、年龄完全匹配的健康志愿者分别进行静息态功能磁共振成像(resting-state functional magnetic resonance imaging,rs-fMRI)检查.以左侧初级运动皮质(primary motor cortex,M1,对应病灶侧)内与手运动功能相关的区域为感兴趣区,基于体素水平的全脑功能连接方法 分析手运动相关的正网络和负网络;进一步基于感兴趣区水平的功能连接方法 分析正负网络内和网络间功能连接的变化;最后,将卒中患者异常的功能连接指标与上肢运动功能评分进行相关性分析.结果 卒中组与病灶侧M1功能连接显著大于对照组的脑区均在负网络内;而显著小于对照组的脑区均在正网络内;卒中组正负网络内和网络间的功能连接强度均显著降低;且病灶侧M1与负网络内同侧额中回的功能连接系数与上肢运动功能评分呈负相关(r=-0.735,P<0.01).结论 脑卒中后与手运动相关脑区的正负网络连接强度均下降.尤其是卒中组大于对照组的功能连接可能并非意味相关脑区的"功能代偿",而是反映了手运动相关脑区之间的负性功能连接降低,这将更有利于深入理解脑卒中神经作用机制并为康复干预提供参考价值.

Our recent study reported that adolescent-onset schizophrenia showed an uncoupling between intraventricular brain temperature (iBT) and local spontaneous brain activity (SBA). While auditory verbal hallucinations (AVH) are common in schizophrenia, the role of AVH in the iBT-SBA relationship is unclear. The current study recruited 24 drug-naïve schizophrenia patients with AVH, 20 patients without AVH and 30 matched healthy controls (HC). We used a diffusion-weighted imaging (DWI) based thermometry method to calculate the iBT for each participant and used both regional homogeneity and amplitude of low-frequency fluctuation methods to assess the SBA. One-way ANOVA was used to detect group differences in iBT, and a partial correlation analysis controlling for lateral ventricles volume, sex and age was applied to detect the relationships between iBT and SBA across the three groups. The results demonstrated that the AVH group showed a significant coupling between iBT and SBA in the bilateral lingual gyrus, left superior occipital gyrus and caudate compared with the other two groups, and no uncoupling was found in the two patients groups relative to HCs. These findings suggest that AVH may modulate the relationship between iBT and SBA in schizophrenia-related regions.

目的:运用静息态功能性磁共振成像探究不同程度运动功能障碍脑卒中的脑局部一致性(regional homogeneity,ReHo)变化.方法:对单侧皮质下脑卒中患者(其中轻度和重度运动功能障碍患者各13例)和13例健康志愿者分别进行静息态功能磁共振成像检查.分别计算三组被试的全脑ReHo值,运用双样本t检验得到组间的差异脑区,进一步将差异脑区的ReHo值与临床上肢运动功能评分及手腕运动功能评分作相关性分析.结果:与健康对照组比较,轻度组病灶同侧皮质下的尾状核和丘脑的ReHo显著减小,辅助运动区及病灶对侧颞下回、梭状回及小脑的ReHo显著增高.重度组病灶同侧的初级运动皮质、扣带前回、颞下回、脑岛、枕中回及丘脑的ReHo显著减小,病灶对侧额上回、颞下回及小脑的ReHo显著增高.患者子组比较,重度组病灶同侧枕中回和病灶对侧颞上回的ReHo均显著低于轻度组,其中枕中回的ReHo值与上肢和“手+腕”FMA(Fugl-Meyer Assessment)评分显示正相关(分别为r=0.647,r=0.682,P＜0.001),颞上回的ReHo值亦与上肢和“手+腕”FMA评分显示正相关(分别为r=0.646,r=0.718,P＜0.001).结论:单侧皮质下脑卒中运动功能障碍静息态神经功能活动异常与运动功能严重程度密切相关,主要涉及邻近病灶的皮质下组织和远离病灶的脑皮质.其中一些脑区的ReHo值与患者运动功能评分存在相关性,或许说明ReHo分析可以作为评估卒中患者运动功能障碍的一个重要影像学指标.

Objective To measure the efficacy of combining motor imagery training ( MIT) with convention-al therapy in improving stroke patients′upper-extremity function. And to seek a cortical reorganization mechanism as-sociated with the improvement using resting-state functional magnetic resonance imaging ( rs-fMRI) . Methods Ten stroke survivors were selected as an experimental group. They were given motor imagery training for four weeks ( 30 minutes a day, 5 days a week) and conventional rehabilitation therapy ( 40 minutes a day, 5 days a week) . Another 10 healthy counterparts were the control group. Before and after the four weeks of treatment, both groups were as-sessed using the upper extremity Fugl-Meyer assessment ( FMA-UE) and the modified Barthel index ( MBI) . Moreo-ver, rs-fMRI was conducted to assess functional connectivity between cortical regions and the ipsilesional primary mo-tor cortex ( M1) before and after the intervention. The laterality index ( LI) of the primary motor or sensory cortex was also calculated. Results After the intervention, the average FMA-UE and MBI scores of the experimental group had increased significantly. After MIT and conventional therapy there was increased functional connectivity between the ip-silesional and contralesional M1 areas, and between the ipsilesional M1 and contralesional primary sensory cortex ( S1) and frontal lobe, the functional connection between the ipsilesional M1 and the ipsilesional paracentral lobule and the anterior cingutate was also increased. More specifically, the LI relating M1 and S1 decreased after the inter-vention, tending toward the normal level. LIMI decreased significantly. Conclusion The 4-week regimen of motor imagery training and conventional therapy resulted in functional improvement in the upper limbs and greater ability in the activities of daily living. The observed improvements may be due to cortical reorganization, including better func-tional connectivity between the bilateral M1 areas and increased connectivity between the ipsilesional M1 area and some non-motor areas. There is some recovery of symmetry in the bilateral primary motor cortex.

PURPOSE:A recent study has reported that schizophrenia patients show an uncoupled association between intraventricular brain temperature (BT) and cerebral blood flow (CBF). CBF has been found to be closely coupled with spontaneous brain activities (SBAs) derived from resting-state BOLD fMRI metrics. Yet, it is unclear so far whether the relationship between the intraventricular BT and the SBAs may change in patients with adolescent-onset schizophrenia (AOS) compared with that in healthy controls (HCs).METHODS:The present study recruited 28 first-episode, drug-naïve AOS patients and 22 matched HCs. We measured the temperature of the lateral ventricles (LV) using diffusion-weighted imaging thermometry and measured SBAs using both regional homogeneity and amplitude of low-frequency fluctuation methods. A nonparametric Wilcoxon rank sum test was used to detect the difference in intraventricular BT between AOS patients and HCs with LV volume, age, and sex as covariates. We also evaluated the relationship between the intraventricular BT and the SBAs using partial correlation analysis controlling for LV volume, age, and sex.RESULTS:We found that HCs showed a significant negative correlation between the intraventricular BT and the local SBAs in the bilateral putamina and left superior temporal gyrus, while such a correlation was absent in AOS patients. Additionally, no significant difference between the two groups was found in the intraventricular BT.CONCLUSION:These findings suggest that AOS patients may experience an uncoupling between intraventricular BT and SBAs in several schizophrenia-related brain areas, which may be associated with the altered relationships among intraventricular BT, CBF, and metabolism.