Altered spontaneous brain activity patterns in hypertensive retinopathy using fractional amplitude of low-frequency fluctuations:a functional magnetic resonance imaging study

AIM:To study functional brain abnormalities in patients with hypertensive retinopathy(HR)and to discuss the pathophysiological mechanisms of HR by fractional amplitude of low-frequency fluctuations(fALFFs)method.METHODS:Twenty HR patients and 20 healthy controls(HCs)were respectively recruited.The age,gender,and educational background characteristics of the two groups were similar.After functional magnetic resonance imaging(fMRI)scanning,the subjects’spontaneous brain activity was evaluated with the fALFF method.Receiver operating characteristic(ROC)curve analysis was used to classify the data.Further,we used Pearson’s correlation analysis to explore the relationship between fALFF values in specific brain regions and clinical behaviors in patients with HR.RESULTS:The brain areas of the HR group with lower fALFF values than HCs were the right orbital part of the middle frontal gyrus(RO-MFG)and right lingual gyrus.In contrast,the values of fALFFs in the left middle temporal gyrus(MTG),left superior temporal pole(STP),left middle frontal gyrus(MFG),left superior marginal gyrus(SMG),left superior parietal lobule(SPL),and right supplementary motor area(SMA)were higher in the HR group.The results of a t-test showed that the average values of fALFFs were statistically significantly different in the HR group and HC group(P<0.001).The fALFF values of the left middle frontal gyrus in HR patients were positively correlated with anxiety scores(r=0.9232;P<0.0001)and depression scores(r=0.9682;P<0.0001).CONCLUSION:fALFF values in multiple brain regions of HR patients are abnormal,suggesting that these brain regions in HR patients may be dysfunctional,which may help to reveal the pathophysiological mechanisms of HR.

Changes in the amplitude of low-frequency fluctuations in specific frequency bands in major depressive disorder after electroconvulsive therapy

BACKGROUND Major depressive disorder(MDD)tends to have a high incidence and high suicide risk.Electroconvulsive therapy(ECT)is currently a relatively effective treatment for MDD.However,the mechanism of efficacy of ECT is still unclear.AIM To investigate the changes in the amplitude of low-frequency fluctuations in specific frequency bands in patients with MDD after ECT.METHODS Twenty-two MDD patients and fifteen healthy controls(HCs)were recruited to this study.MDD patients received 8 ECT sessions with bitemporal placement.Resting-state functional magnetic resonance imaging was adopted to examine regional cerebellar blood flow in both the MDD patients and HCs.The MDD patients were scanned twice(before the first ECT session and after the eighth ECT session)to acquire data.Then,the amplitude of low-frequency fluctuations(ALFF)was computed to characterize the intrinsic neural oscillations in different bands(typical frequency,slow-5,and slow-4 bands).RESULTS Compared to before ECT(pre-ECT),we found that MDD patients after the eighth ECT(post-ECT)session had a higher ALFF in the typical band in the right middle frontal gyrus,posterior cingulate,right supramarginal gyrus,left superior frontal gyrus,and left angular gyrus.There was a lower ALFF in the right superior temporal gyrus.Compared to pre-ECT values,the ALFF in the slow-5 band was significantly increased in the right limbic lobe,cerebellum posterior lobe,right middle orbitofrontal gyrus,and frontal lobe in post-ECT patients,whereas the ALFF in the slow-5 band in the left sublobar region,right angular gyrus,and right frontal lobe was lower.In contrast,significantly higher ALFF in the slow-4 band was observed in the frontal lobe,superior frontal gyrus,parietal lobe,right inferior parietal lobule,and left angular gyrus.CONCLUSION Our results suggest that the abnormal ALFF in pre-and post-ECT MDD patients may be associated with specific frequency bands.

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 nonexophthalmos(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 bestcorrected 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.

Dynamic alterations of amplitude of low-frequency fluctuations in patients with chronic neck pain

Background:The pathogenesis of neck pain in the brain,which is the fourth most common cause of disability,remains unclear.Furthermore,little is known about the characteristics of dynamic local functional brain activity in cervical pain.Objective:The present study aimed to investigate the changes of local brain activity caused by chronic neck pain and the factors leading to neck pain.Methods:Using the amplitude of low-frequency fluctuations(ALFF)method combined with sliding window approach,we compared local brain activity that was measured by the functional magnetic resonance imaging(fMRI)of 107 patients with chronic neck pain(CNP)with that of 57 healthy control participants.Five pathogenic factors were selected for correlation analysis.Results:The group comparison results of dynamic amplitude of low-frequency fluctuation(dALFF)variability showed that patients with CNP exhibited decreased dALFF variability in the left inferior temporal gyrus,the middle temporal gyrus,the angular gyrus,the inferior parietal marginal angular gyrus,and the middle occipital gyrus.The abnormal dALFF variability of the left inferior temporal gyrus was negatively correlated with the average daily working hours of patients with neck pain.Conclusions:The findings indicated that the brain regions of patients with CNP responsible for audition,vision,memory,and emotion were subjected to temporal variability of abnormal regional brain activity.Moreover,the dALFF variability in the left inferior temporal gyrus might be a risk factor for neck pain.This study revealed the brain dysfunction of patients with CNP from the perspective of dynamic local brain activity,and highlighted the important role of dALFF variability in understanding the neural mechanism of CNP.

Survivors of COVID-19 exhibit altered amplitudes of low frequency fluctuation in the brain: a resting-state functional magnetic resonance imaging study at 1-year follow-up

Although some short-term follow-up studies have found that individuals recovering from coronavirus disease 2019(COVID-19)exhibit anxiety,depression,and altered brain microstructure,their long-term physical problems,neuropsychiatric sequelae,and changes in brain function remain unknown.This observational cohort study collected 1-year follow-up data from 22 patients who had been hospitalized with COVID-19(8 males and 11 females,aged 54.2±8.7 years).Fatigue and myalgia were persistent symptoms at the 1-year follow-up.The resting state functional magnetic resonance imaging revealed that compared with 29 healthy controls(7 males and 18 females,aged 50.5±11.6 years),COVID-19 survivors had greatly increased amplitude of low-frequency fluctuation(ALFF)values in the left precentral gyrus,middle frontal gyrus,inferior frontal gyrus of operculum,inferior frontal gyrus of triangle,insula,hippocampus,parahippocampal gyrus,fusiform gyrus,postcentral gyrus,inferior parietal angular gyrus,supramarginal gyrus,angular gyrus,thalamus,middle temporal gyrus,inferior temporal gyrus,caudate,and putamen.ALFF values in the left caudate of the COVID-19 survivors were positively correlated with their Athens Insomnia Scale scores,and those in the left precentral gyrus were positively correlated with neutrophil count during hospitalization.The long-term follow-up results suggest that the ALFF in brain regions related to mood and sleep regulation were altered in COVID-19 survivors.This can help us understand the neurobiological mechanisms of COVID-19-related neuropsychiatric sequelae.This study was approved by the Ethics Committee of the Second Xiangya Hospital of Central South University(approval No.2020 S004)on March 19,2020.

AMPLITUDE OF LOW FREQUENCY FLUCTUATION AT DIFFERENT FREQUENCY BANDS IN EARLY AMNESTIC MILD COGNITIVE IMPAIRMENT: RESULTS FROM ADNI

We used resting-state functional magnetic resonance imaging(fMRI)to determine whether there are any abnormalities in different frequency bands between amplitude of low-frequency fluctuations(ALFF)and fractional ALFF(fALFF)and between 10 early amnestic mild cognitive impairment(EMCI)patients and eight normal controls participating in the Alzheimer’s Disease Neuroimaging Initiative(ADNI).We showed widespread difference in ALFF/fALFF between two frequency bands(slow-4:0.027-0.073 Hz,slow-5:0.01-0.027 Hz)in many brain areas including posterior cingulate cortex(PCC),medial prefrontal cortex(MPFC),suprasellar cistern(SC)and ambient cistern(AC).Compared to the normal controls,the EMCI patients showed increased ALFF values in PCu,cerebellum,occipital lobe and cerebellum posterior lobe in frequency band slow-4.While in frequency band slow-5,the EMCI patients showed decreased ALFF values in temporal lobe,left cerebrum and middle temporal gyrus5.Moreover,the EMCI patients showed increased fALFF values in frontal lobe and inferior frontal gyrus in band slow-5.While in frequency band slow-4,the EMCI patients showed decreased fALFF values in limbic lobe,cingulate gyrus and corpus callosum.These results demonstrated that EMCI patients had widespread abnormalities of amplitude of LFF in different frequency bands.

基于动态低频振幅机器学习对无先兆偏头痛相关睡眠障碍的机制探究

目的:采用动态低频振幅技术(dALFF)结合监督学习模型探讨无先兆偏头痛(患者睡眠障碍)的神经影像机制。方法:收集52名确诊为无先兆偏头痛的患者,根据匹兹堡睡眠质量指数将其分为偏头痛伴睡眠障碍组(MwSD)与偏头痛不伴睡眠障碍组(MwoSD),并同期招募40名年龄与性别相匹配的健康志愿者作为对照组。使用3.0 T MRI采集其T1WI和BOLD-fMRI图像,通过随机森林(RF)、逻辑回归(LR)、支持向量机(SVM)机器学习算法对其dALFF进行分析。结果:单因素方差分析(one-way ANOVA)显示3组受试者在左侧丘脑、右侧枕中回、左侧楔前叶dALFF有差异;两独立样本t检验显示MwSD组较MwoSD组左内侧和旁扣带回、左侧额中回dALFF值升高,右侧颞上回dALFF值下降;无监督学习模型中SVM性能较好,权重绝对值排名前三的脑区右侧枕中回、左侧楔前叶、左内侧和旁扣带回,均与视觉通路相关。结论:视觉通路相关脑区dALFF值可作为预测MwSD患者的神经影像学标志。

Neuropathological characteristics of abnormal white matter functional signaling in adolescents with major depression

BACKGROUND Major depression disorder(MDD)constitutes a significant mental health concern.Epidemiological surveys indicate that the lifetime prevalence of depression in adolescents is much higher than that in adults,with a corresponding increased risk of suicide.In studying brain dysfunction associated with MDD in adolescents,research on brain white matter(WM)is sparse.Some researchers even mistakenly regard the signals generated by the WM as noise points.In fact,studies have shown that WM exhibits similar blood oxygen level-dependent signal fluctuations.The alterations in WM signals and their relationship with disease severity in adolescents with MDD remain unclear.AIM To explore potential abnormalities in WM functional signals in adolescents with MDD.METHODS This study involved 48 adolescent patients with MDD and 31 healthy controls(HC).All participants were assessed using the Patient Health Questionnaire-9 Scale and the mini international neuropsychiatric interview(MINI)suicide inventory.In addition,a Siemens Skyra 3.0T magnetic resonance scanner was used to obtain the subjects'image data.The DPABI software was utilized to calculate the WM signal of the fractional amplitude of low frequency fluctuations(fALFF)and regional homogeneity,followed by a two-sample t-test between the MDD and HC groups.Independent component analysis(ICA)was also used to evaluate the WM functional signal.Pearson’s correlation was performed to assess the relationship between statistical test results and clinical scales.RESULTS Compared to HC,individuals with MDD demonstrated a decrease in the fALFF of WM in the corpus callosum body,left posterior limb of the internal capsule,right superior corona radiata,and bilateral posterior corona radiata[P<0.001,family-wise error(FWE)voxel correction].The regional homogeneity of WM increased in the right posterior limb of internal capsule and left superior corona radiata,and decreased in the left superior longitudinal fasciculus(P<0.001,FWE voxel correction).The ICA results of WM overlapped with those of regional homogeneity.The fALFF of WM signal in the left posterior limb of the internal capsule was negatively correlated with the MINI suicide scale(P=0.026,r=-0.32),and the right posterior corona radiata was also negatively correlated with the MINI suicide scale(P=0.047,r=-0.288).CONCLUSION Adolescents with MDD involves changes in WM functional signals,and these differences in brain regions may increase the risk of suicide.

基于MRI-DWI的影像组学在预测鼻咽癌淋巴结转移中的价值

目的:探讨基于MRI弥散加权成像(DWI)的影像组学模型在预测鼻咽癌淋巴结转移中的价值。方法:回顾性收集我院初诊的鼻咽癌患者,所有患者均行PET-CT检查,将淋巴结定义为转移淋巴结(n=81)与非转移淋巴结(n=43)。将DWI图像导入3D-Slicer软件,并对体积>1 cm^(3)的淋巴结进行分割,提取851个影像组学特征,包括一阶特征、形状特征、纹理特征、小波变换后的特征。采用观察者一致性检验、最大相关最小冗余算法、最小绝对收缩和选择算子算法进行组学特征选择,采用logistic回归模型构建预测模型;采用受试者工作特征(ROC)曲线分析模型的诊断效能。结果:最终筛选出5个影像组学特征纳入影像组学模型,ROC曲线下面积(AUC)在训练组和验证组均为0.89。进一步将临床参数Ki-67纳入模型后,联合模型中的AUC在训练组和验证组分别为0.92(95%CI 0.84~0.97)、0.91(95%CI 0.77~0.98)。结论:基于DWI的影像组学模型有望用于早期无创评估鼻咽癌淋巴结转移。

首发及复发抑郁症病人动态低频振幅静息态fMRI研究

目的采用功能MRI(fMRI)技术,通过动态低频振幅(dALFF)分析来检测首发(FE)、复发(RE)抑郁症病人和健康对照(HC)之间脑自发活动的动态异常。方法作为前瞻性研究纳入了FE病人68例和RE病人42例,均完成汉密顿抑郁量表(HAMD-17)和病人健康问卷(PHQ-9)评定。另招募与病人性别、年龄相匹配的110例健康人作为HC组,均完成PHQ-9评定。采集所有受试者的静息态fMRI影像。采用DPABI软件对fMRI数据进行预处理,采用单因素协方差分析比较3组间dALFF差异。在3组间dALFF有差异脑区中测算时间序列均值(dALFF值),事后两两比较采用Bonferroni校正的LSD-t检验。采用不同的窗宽、步长和窗类型对上述分析进行验证。结果FE和RE组的PHQ-9评分均高于HC组(均P<0.05),FE和RE组的PHQ-9、HAMD-17评分差异无统计学意义(均P>0.05)。3组间右侧枕中回dALFF值的差异有统计学意义(P<0.05,FWE校正),事后两两比较发现FE、RE组右侧枕中回的dALFF值均低于HC组(均P<0.016),而FE、RE组间差异无统计学意义(P>0.05)。采用不同参数组合进行验证,结果均一致。结论FE和RE抑郁症病人均表现出右侧枕中回脑自发活动的动态性降低,提示其对外部信息处理的灵活性下降,且这可能是抑郁症病人的特质性异常。

dALFF分析方法在不同认知功能状态系统性红斑狼疮病人中的应用

目的采用动态低频振幅(dALFF)分析不同认知功能状态的系统性红斑狼疮(SLE)病人的动态脑功能变化特点,寻找可能的影像标志物以反映SLE病人认知功能的变化。方法前瞻性收集38例女性SLE病人和44例健康对照者的静息态脑影像数据,根据蒙特利尔认知评估量表(MoCa)得分将SLE病人分为2组,认知正常组(MoCa-H)18例,认知减低组(MoCa-L)20例。使用滑窗技术计算3组受试者的dALFF值,3组间dALFF值的比较采用单因素方差分析,进一步两两比较采用LSD-t事后检验。采用受试者操作特征(ROC)曲线分析差异脑区dALFF值区分不同认知状态SLE病人的诊断效能;采用Spearman相关分析差异脑区dALFF值与神经量表、临床数据之间的相关性。结果3组间双侧颞极颞上回、双侧海马、左侧眶部额上回、左侧颞上回、右侧尾状核、左侧角回的dALFF值差异有统计学意义(均P<0.05,FDR校正);MoCa-H、MoCa-L组上述脑区dALFF值均高于健康对照组(均P<0.05);MoCa-H组左侧眶部额上回、右侧尾状核dALFF值低于MoCa-L组。部分差异脑区的dALFF值鉴别3组具有较好的诊断效能。相关性分析显示,右侧尾状核dALFF值与MoCa得分、血清生物学指标C4呈负相关(r=-0.391,P=0.037;r=-0.368,P=0.023)。结论部分差异脑区的dALFF值在区分不同认知水平SLE病人及健康对照者表现出较好的诊断效能。SLE病人dALFF值与临床数据、神经量表之间具有一定的相关性,可能作为监测SLE病人疾病变化的影像学标志物。

Local synchronization and amplitude of the fluctuation of spontaneous brain activity in attention-deficit/hyperactivity disorder:a resting-state fMRI study

Regional homogeneity（ReHo）and the amplitude of low-frequency fluctuation（ALFF）are two approaches to depicting different regional characteristics of resting-state functional magnetic resonance imaging（RS-fMRI）data.Whether they can complementarily reveal brain regional functional abnormalities in attention-deficit/hyperactivity disorder（ADHD）remains unknown.In this study,we applied ReHo and ALFF to 23 medication-na ve boys diagnosed with ADHD and 25 age-matched healthy male controls using whole-brain voxel-wise analysis.Correlation analyses were conducted in the ADHD group to investigate the relationship between the regional spontaneous brain activity measured by the two approaches and the clinical symptoms of ADHD.We found that the ReHo method showed widely-distributed differences between the two groups in the fronto-cingulo-occipitocerebellar circuitry,while the ALFF method showed a difference only in the right occipital area.When a larger smoothing kernel and a more lenient threshold were used for ALFF,more overlapped regions were found between ALFF and ReHo,and ALFF even found some new regions with group differences.The ADHD symptom scores were correlated with the ReHo values in the right cerebellum,dorsal anterior cingulate cortex and left lingual gyrus in the ADHD group,while no correlation was detected between ALFF and ADHD symptoms.In conclusion,ReHo may be more sensitive to regional abnormalities,at least in boys with ADHD,than ALFF.And ALFF may be complementary to ReHo in measuring local spontaneous activity.Combination of the two may yield a more comprehensive pathophy-siological framework for ADHD.

Low-frequency fluctuation in continuous real-time feedback of finger force:a new paradigm for sustained attention

Objective Behavioral studies have suggested a low-frequency（0.05 Hz） fluctuation of sustained attention on the basis of the intra-individual variability of reaction-time.Conventional task designs for functional magnetic resonance imaging（fMRI） studies are not appropriate for frequency analysis.The present study aimed to propose a new paradigm,real-time finger force feedback（RT-FFF）,to study the brain mechanisms of sustained attention and neurofeedback.Methods We compared the low-frequency fluctuations in both behavioral and fMRI data from 38 healthy adults（19 males;mean age,22.3 years）.Two fMRI sessions,in RT-FFF and sham finger force feedback（S-FFF） states,were acquired（TR 2 s,Siemens Trio 3-Tesla scanner,8 min each,counter-balanced）.Behavioral data of finger force were obtained simultaneously at a sampling rate of 250 Hz.Results Frequency analysis of the behavioral data showed lower amplitude in the lowfrequency band（0.004-0.104 Hz） but higher amplitude in the high-frequency band（27.02-125 Hz） in the RT-FFF than the S-FFF states.The mean finger force was not significantly different between the two states.fMRI data analysis showed higher fractional amplitude of low-frequency fluctuation（fALFF） in the S-FFF than in the RT-FFF state in the visual cortex,but higher fALFF in RT-FFF than S-FFF in the middle frontal gyrus,the superior frontal gyrus,and the default mode network.Conclusion The behavioral results suggest that the proposed paradigm may provide a new approach to studies of sustained attention.The fMRI results suggest that a distributed network including visual,motor,attentional,and default mode networks may be involved in sustained attention and/or real-time feedback.This paradigm may be helpful for future studies on deficits of attention,such as attention deficit hyperactivity disorder and mild traumatic brain injury.

基于静息态fMRI的睡眠剥夺百分比振幅动态变化研究

目的基于百分比振幅(percent amplitude of fluctuation,perAF)指标探讨睡眠剥夺(sleep deprivation,SD)过程中大脑自发功能活动的动态变化过程。材料与方法前瞻性招募36名健康志愿者分别于22时、24时、2时、4时及6时采集静息态功能磁共振成像(functional magnetic resonance imaging,fMRI)图像,同时利用斯坦福嗜睡量表(Stanford Sleepiness Scale,SSS)收集个体睡眠状态数据。应用单因素重复测量方差分析比较多时间全脑perAF值动态变化存在差异的脑区(P<0.05,FDR校正)。同时使用Pearson相关分析探讨差异脑区的perAF值动态变化与SSS分数的相关性。结果双侧丘脑、右侧中央前回、右侧顶上小叶、左内侧前额叶及右侧颞上回的perAF值存在显著的时间主效应(FDR校正,P<0.05,团块大小≥20体素),即上述脑区的perAF值在五个时间点中至少有两个时间点存在显著性差异,且发现22时与6时的右侧颞上回(r=0.36,P=0.03;r=0.37,P=0.02)及左内侧前额叶(r=0.33,P=0.05;r=0.41,P=0.01)perAF值与SSS分数呈显著正相关。结论默认模式网络、额顶注意力网络及丘脑的异常活动可能是SD过程中个体嗜睡程度增加及注意力下降的重要神经机制。

基于动态低频振幅法的青少年吸烟成瘾问题研究

该文采用动态低频振幅(dynamic amplitude of low frequency fluctuation,dALFF)方法探究青少年吸烟成瘾者脑功能网络的异常,为理解青少年吸烟成瘾的机制提供新视角。通过独立成分分析、滑动窗口法、K-means聚类方法分析青少年吸烟成瘾者在默认模式网络(default mode network,DMN)、左侧执行控制网络(left executive control network,LECN)、右侧执行控制网络(right executive control network,RECN)和突显网络(salience network,SAN)的动态低频振幅(dALFF)异常。同时,使用皮尔逊相关性分析评估动态指标(时间分数和平均停留时间)与吸烟统计学数据(FTND,烟龄,包年)的关系。相较于青少年健康非吸烟者,青少年吸烟成瘾者在默认模式网络(DMN)、左侧执行控制网络(LECN)、右侧执行控制网络(RECN)和突显网络(SAN)的激活程度降低,皮尔逊相关性分析表明dALFF在状态2时的平均停留时间和包年呈显著正相关。吸烟成瘾会导致青少年的部分脑功能网络异常,其激活程度会降低,同时这些脑区的功能异常与吸烟者的包年存在关联。

基于动态低频振荡振幅方法的乒乓球运动员脑可塑性变化

目的利用静息态功能磁共振成像(rs-fMRI)技术,选取动态低频振荡振幅(dynamic amplitude of lowfrequency fluctuation,dALFF)方法,动态探测不同训练程度的乒乓球运动员脑功能活动的可塑性变化,以更精确地分析乒乓球项目特征,并为乒乓球运动员的训练监控与评价提供科学依据。方法招募乒乓球专业队运动员、专业体育院校乒乓球专项学生以及性别、年龄与之匹配的普通被试,分别进行乒乓球训练情况调查。采集3组被试rs-fMRI相关数据,计算大脑dALFF指标并进行方差分析,提取差异脑区的dALFF值做双样本t检验并做Bonferroni校正;同时分别将组间差异脑区dALFF值与运动员周训练时长进行Pearson相关分析。结果 3组被试左侧小脑及左侧颞中回的dALFF值均有显著差异[体素P<0.01,团块P<0.05,高斯随机场(GRF)校正,体素>40]。事后检验发现,大学生运动员/专业运动员左侧小脑dALFF值均显著高于普通被试(P<0.05),大学生运动员左侧颞中回dALFF值显著高于其他2组被试(P<0.05),且均呈现大学生运动员>专业运动员>普通被试的变化趋势。专业运动员左侧小脑及左侧颞中回dALFF值与周训练时长均不存在相关性(P>0.05),而大学生运动员左侧小脑及左侧颞中回dALFF值与周训练时长呈显著负相关(r值分别为–0.4382和–0.4115,均P<0.05)。结论乒乓球运动可以引起大脑可塑性变化。乒乓球运动员在不同训练程度下可发生大脑(快速)运动平衡和视觉运动协调相关脑区的功能变化,其局部脑区脑自发活动的变异性在运动训练前期强于后期,且随着训练时长的增加,脑自发活动趋于稳定。

青少年心境动态发展特点研究

本文在提出的心境动态平衡模型思想的指导下,在自然条件下对青少年进行28天的连续追踪,运用动态系统理论考察了青少年的心境波动幅度、波动频率以及波动周期。结果发现青少年心境主基调偏向积极状态,初中生的心境波动幅度高于大学生,女生的波动频率高于男生;青少年的心境波动周期为近似7天和28天。

基于动态低频振幅的有氧运动训练后大脑功能可塑性研究

为运动影响大脑功能、结构可塑性的神经机制研究提供客观的影像学证据。基于静息态功能磁共振成像和结构磁共振成像,采用动态低频振幅及基于体素的形态学测量方法,分析中等强度有氧训练后大脑功能活动及灰质体积的变化,纳入20名健康成年被试者参与6个月有氧运动训练。采集所有被试者运动训练前后rs-fMRI和结构磁共振数据并进行dALFF及VBM分析,提取差异脑区。结果显示:6个月中等强度有氧运动训练后,右侧颞中回、海马旁回、中央后回、楔前叶等脑区的dALFF较训练前增高;左侧额下回、额中回以及右侧的缘上回、角回等脑区的dALFF较训练前降低。研究认为,中等强度有氧运动训练可以引起大脑执行控制网络及额顶网络相关脑区功能可塑性改变。

基于动态低频振幅方法的飞行员静息态fMRI研究

探讨了动态低频振幅法(dynamic amplitude of low frequency fluctuation,dALFF)在民用航空运输飞行员静息状态脑功能评价及飞行员课程开发中的应用价值。通过招募26名民航飞行员以及学历、性别、年龄与之相匹配的23名普通职业者进行磁共振成像扫描,计算被试者大脑的动态低频振幅指标并进行组间对比。发现飞行员与普通职业者的动态低频振幅(dALFF)值有明显的差异(P<0.01,GRF校正),具体差异脑区为飞行员的左三角部额下回、右额中回、右中央后回三个脑区相较健康对照组降低。研究表明了经过长期的飞行训练,飞行员在躯体感觉相关的脑区的活动变异性减低。