A dynamic causal modeling analysis of the effective connectivities underlying top-down letter processing

The present study employed dynamic causal modeling to investigate the effective functional connectivity between regions of the neural network involved in top-down letter processing. We used an illusory letter detection paradigm in which participants detected letters while viewing pure noise images. When participants detected letters, the response of the right middle occipital gyrus (MOG) in the visual cortex was enhanced by increased feed-backward connectivity from the left inferior frontal gyrus (IFG). In addition, illusory letter detection increased feed-forward connectivity from the right MOG to the left inferior parietal lobules. Originating in the left IFG, this top-down letter processing network may facilitate the detection of letters by activating letter processing areas within the visual cortex. This activation in turns may highlight the visual features of letters and send letter information to activate the associated phonological representations in the identified parietal region.     

Structural changes in the gray matter of unmedicated patients with obsessive-compulsive disorder: a voxel-based morphometric study

The aim of the current study was to use whole brain voxel-based morphometry（VBM）to assess the gray matter（GM）changes in unmedicated patients with obsessive-compulsive disorder（OCD）compared with normal controls.We compared the GM volumes in28 patients with 22 matched healthy controls using a1.5T MRI.Three-dimensional T1-weighted magnetic resonance images were obtained from all participants.VBM was performed to detect GM volume differences between the two groups.We detected increased regional GM volumes in the bilateral middle temporal gyri,bilateral middle occipital gyri,bilateral globus pallidus,right inferior parietal gyrus,left superior parietal gyrus,right parahippocampus,right supramarginal gyrus,right medial superior frontal gyrus,and left inferior frontal opercular cortex in the OCD patients relative to controls（P〈0.001,uncorrected,cluster size〉100 voxels）.No decreased GM volume was found in the OCD group compared with normal controls.Our findings suggest that structural changes in the GM are not limited to fronto-striato-thalamic circuits in the pathogenesis of OCD.Temporo-parietal cortex may also play an important role.     

Correlation between white matter damage and gray matter lesions in multiple sclerosis patients

We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe(superior frontal, middle frontal, precentral, and orbital gyri), right parietal lobe(postcentral and inferior parietal gyri), right temporal lobe(caudate nucleus), right occipital lobe(middle occipital gyrus), right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.     

Differential effects of hunger and satiety on insular cortex and hypothalamic functional connectivity

The insula cortex and hypothalamus are implicated in eating behaviour, and contain receptor sites for peptides and hormones controlling energy balance. The insula encompasses multi‐functional subregions, which display differential anatomical and functional connectivities with the rest of the brain. This study aimed to analyse the effect of fasting and satiation on the functional connectivity profiles of left and right anterior, middle, and posterior insula, and left and right hypothalamus. It was hypothesized that the profiles would be altered alongside changes in homeostatic energy balance. Nineteen healthy participants underwent two 7‐min resting state functional magnetic resonance imaging scans, one when fasted and one when satiated. Functional connectivity between the left posterior insula and cerebellum/superior frontal gyrus, and between left hypothalamus and inferior frontal gyrus was stronger during fasting. Functional connectivity between the right middle insula and default mode structures (left and right posterior parietal cortex, cingulate cortex), and between right hypothalamus and superior parietal cortex was stronger during satiation. Differences in blood glucose levels between the scans accounted for several of the altered functional connectivities. The insula and hypothalamus appear to form a homeostatic energy balance network related to cognitive control of eating; prompting eating and preventing overeating when energy is depleted, and ending feeding or transferring attention away from food upon satiation. This study provides evidence of a lateralized dissociation of neural responses to energy modulations.     

Altered structure and functional connection in patients with classical trigeminal neuralgia

Classical trigeminal neuralgia (TN) is a specific type of neuropathic orofacial pain of which the plasticity of brain structure and connectivity have remained largely unknown. A total of 62 TN patients were included and referred to MRI scans. Voxel‐based morphometry was used to analyze the change of gray matter volume. Resting‐state functional imaging was used to analyze the connectivity between brain regions. The results showed gray matter volume reduction in components of the prefrontal cortex, precentral gyrus, cerebellar tonsil, thalamus, hypothalamus, and nucleus accumbens among right TN patient and in the inferior frontal gyrus, precentral gyrus, cerebellum, thalamus, ventral striatum, and putamen among left TN patients. The connections between the right superior frontal gyrus and right middle frontal gyrus were lower in right TN patients. The connection between the left precentral gyrus and the left superior frontal gyrus was lower while the connection between bilateral thalamus was higher in left TN patients. The changes of volume in bilateral thalamus of right TN patients and left ventral striatum of left TN patients, and the connectivity between bilateral thalamus of left TN patients were moderately correlated with pain duration. These findings suggest that brain regions such as the thalamus may not only be involved in processing of pain stimuli but also be important for the development of TN. The left hemisphere may be dominant in processing and modulation of TN pain signal. Chronification of TN induces volume changes in brain regions which are associated with emotional or cognitive modulation of pain. Hum Brain Mapp 39:609–621, 2018. © 2017 Wiley Periodicals, Inc.     

首发精神分裂症患者的脑灰质减少

目的 采用基于体素的形态学(VBM)分析方法对高分辨磁共振图像进行分析,研究首发精神分裂症患者大脑灰质变化,探讨患者脑灰质改变与临床症状之间的关系.方法 对符合CCMD-3诊断标准的首发精神分裂症患者以及健康志愿者各16例进行脑结构核磁共振扫描,并应用VBM进行脑灰质体积分析.所有患者均完成阳性与阴性症状量表(PANSS)评估.结果 与健康对照相比,患者组灰质密度降低的脑区有右侧小脑(t=5.17,P＜0.001)、右侧顶上回(t=5.01,P＜0.001)、左侧颞上回至岛叶被盖(t=4.79,P＜0.001)、左侧额中回(t=4.71,P＜ 0.001)、左侧额下回(t=4.70,P＜0.001)、右侧舌回(t=4.62,P＜ 0.001)、左侧海马杏仁体(t=4.11,P＜0.001).患者组左侧Heschl's回的灰质密度与PANSS量表总分(r=-0.509,P=0.044)以及PANSS阳性症状量表得分(r=-0.554,P=0.026)呈显著负相关.结论 首发精神分裂症患者的脑灰质减少以左侧额、颞叶为主,其中左侧Heschl's回灰质变化与患者的精神病性症状有相关性.     

Abnormal functional connectivity in patients with vascular cognitive impairment, no dementia: a resting-state functional magnetic resonance imaging study

The functional connectivity (FC) method was used to investigate the changes in the resting state of patients with vascular cognitive impairment, no dementia (VCIND). Resting-state functional magnetic resonance images (fMRIs) were acquired from 16 patients with subcortical ischemic vascular disease (SIVD) who fulfilled the criteria for VCIND, as well as 18 age- and sex-matched subjects with SIVD with no cognitive impairment (control group). Posterior cingulate cortex connectivity was gathered by investigating synchronic low-frequency fMRI signal fluctuations with a temporal correlation method. Compared with the control group, the patients showed FC decrease in the left middle temporal gyrus, the left anterior cingulate/left middle frontal gyrus, the right caudate, the right middle frontal gyrus, and the left medial frontal gyrus/paracentral lobule. There were also some regions that showed increased connectivity. These regions included the right inferior temporal gyrus, the left middle temporal gyrus, the left precentral gyrus, and the left superior parietal lobule. Our findings revealed the change in resting-state patterns of neuronal activity in patients with VCIND. This change may be caused by subcortical white matter lesions that destroyed direct and indirect fiber tract connectivity across the cerebral white matter and influenced the cortical FC and hypoperfusion resulted from small vascular disease. The results of the increased connectivity may be evoked by the compensatory recruitment and plasticity mechanism. Our findings suggest that the simplicity and noninvasiveness of this method makes it a potential tool to help thoroughly understand the pathogenesis of VCIND.     

Voxel-based morphometry study on brain structure in children with high-functioning autism

Earlier studies have suggested abnormal brain volumes in autism, but inconsistencies exist. Using voxel-based morphometry, we compared global and regional brain volumes in 17 high-functioning autistic children with 15 matched controls. We identified significant reduction in left white matter volume and white/gray matter ratio in autism. Regional brain volume reductions were detected for right anterior cingulate, left superior parietal lobule white matter volumes, and right parahippocampal gyrus gray matter volume, whereas enlargements in bilateral supramarginal gyrus, right postcentral gyrus, right medial frontal gyrus, and right posterior lobe of cerebellum gray matter in autism. Our findings showed global and regional brain volumes abnormality in high-functioning autism.     

Voxel-based morphometric analysis on the volume of gray matter in bipolar I disorder

A number of previous studies have found that bipolar disorder is associated with abnormalities of brain structure. In this study we used optimized voxel-based morphometry (VBM) to compare gray matter volume between patients with bipolar I disorder and healthy controls. Twenty-four bipolar I patients (15 males and nine females) and 36 healthy controls (21 males and 15 females), who were well matched for age and gender, were scanned using structural magnetic resonance imaging. Gray matter volume was assessed and compared using optimized VBM, and the correlation between duration of illness/number of episodes and regional volumes was analyzed. There was no difference in whole-brain gray matter volume between the two groups. Optimized vVBM showed that subjects with bipolar I disorder had smaller volumes in the left inferior parietal lobule, right superior temporal gyrus, right middle frontal gyrus and left caudate. Only the volume of the right middle frontal gyrus was correlated with duration of illness and number of episodes in patients. These results suggest widespread gray matter defects in bipolar I disorder, which may play an important role in onset of the illness.     

Voxel-based analyses of gray/white matter volume and diffusion tensor data in major depression

The purpose of this study is to use voxel-based analysis to simultaneously elucidate regional changes in gray/white matter volume, mean diffusivity (MD), and fractional anisotropy (FA) in patients with unipolar major depressive disorder. We studied 21 right-handed patients and 42 age- and gender-matched right-handed normal subjects. Local areas showing significant gray matter volume reduction in depressive patients compared with controls were observed in the right parahippocampal gyrus, hippocampus, bilateral middle frontal gyri, bilateral anterior cingulate cortices, left parietal and occipital lobes, and right superior temporal gyrus. Local areas showing an increase of MD in depressive patients were observed in the bilateral parahippocampal gyri, hippocampus, pons, cerebellum, left frontal and temporal lobes, and right frontal lobe. There was no significant difference between the two groups for FA and white matter volume in the entire brain. Although there was no local area where brain volume and MD were significantly correlated with disease severity, FA tended to correlate negatively with total days depressed in the right anterior cingulate and the left frontal white matter. These results suggest that the frontolimbic neural circuit might play an important role in the neuropathology of patients with major depressive disorder.     

Light to moderate alcohol use is associated with increased cortical gray matter in middle-aged men: a voxel-based morphometric study

We examined the associations of current alcohol consumption with brain morphometric measures in a healthy, community-dwelling cohort. Cranial T1-weighted 3D-structural MRI scans were obtain in 383 adults (men=211) aged 60-64 years, randomly selected form the larger PATH Through Life study. Voxel-based morphometric analyses were applied to detect regional gray matter and white matter volume changes related to reported weekly alcohol consumption (mean 7.04+/-8.15 drinks per week). Alcohol consumption in men had a linear association with greater gray matter in bilateral superior and medial frontal gyrus, bilateral middle occipital gyrus, right inferior parietal gyrus, bilateral precentral gyrus, left paracentral gyrus, left uncus and left inferior occipital gyrus, and with lesser white matter in bilateral superior temporal and left parahippocampal gyrus, after adjustment for age, education, total intracranial volume, smoking, hypertension, diabetes and hyperlipidemia. In women, there was no significant linear association between alcohol consumption and total or regional brain volumes. Our results showed a dose-related, sexually dimorphic impact of alcohol on brain tissue volumes independent of cerebrovascular risk factors. These findings are consistent with an inverse-U association between alcohol use and brain morphometry, while suggesting an increased vulnerability of white matter to alcohol-related brain damage.     

Neurocognitive deficits and prefrontal cortical atrophy in patients with schizophrenia

RATIONALE: Cognitive deficits are of particular importance in schizophrenia since they are strongly associated with poor prognosis. We investigated the relationship between prefrontal cortical atrophy as measured by MRI and the neuropsychological performance of participants diagnosed with DSM-IV-TR schizophrenia. METHODS: Fourteen unmedicated adult patients and thirteen matched controls were studied. Subjects underwent MRI yielding 1 mm isotropic T1-weighted images. Voxel based morphometry was applied to all images using SPM5. The mean gray level of Brodmann area (BA) 9 was also extracted and evaluated using simple regression along with relative score differences on patients neuropsychological tests compared to controls. RESULTS: Patients exhibited a poorer performance on the Controlled Word Association Task (COWAT), Wisconsin Card Sorting Test (WCST) and Trail Making Test (TMT). Patients also presented a greater level of apathy as indexed by the Apathy Evaluation Scale (AES). There was a significant decrease in gray matter volume in patients with schizophrenia in left supplementary motor area, bilateral superior frontal gyrus, left middle frontal gyrus, right opercular area, left angular gyrus, left superior temporal gyrus and left cerebellar hemisphere. Within the schizophrenia group, decreased BA9 gray matter volume was correlated with poorer performance on the WCST and TMT-B. CONCLUSION: Prefrontal gray matter abnormalities in schizophrenia patients may be associated with some symptoms including difficulties with set-shifting and decreased mental flexibility. Further studies evaluating prefrontal connectivity may clarify if such impairment results from abnormalities of the frontal area alone, or are a result of altered networks involving the frontal and extra-frontal areas.     

Putaminal gray matter volume decrease in panic disorder: an optimized voxel-based morphometry study

Our study aimed to identify gray matter volume differences between panic disorder patients and healthy volunteers using optimized voxel-based morphometry. Gray matter volume was compared between 18 panic subjects and 18 healthy volunteers. Panic disorder severity scale (PDSS) and Zung self-rating anxiety scale (Z-SAS) were administered. Gray matter volumes of bilateral putamen were decreased in panic subjects relative to healthy comparison subjects (corrected P < 0.05). Decreased gray matter volume was also observed in the right precuneus, right inferior temporal gyrus, right inferior frontal gyrus, left superior temporal gyrus, and left superior frontal gyrus at a less conservative level of significance. PDSS score negatively correlated with gray matter volume in the left putamen, right putamen, right inferior frontal gyrus, and left superior frontal gyrus in panic subjects. The duration of illness negatively correlated with left putaminal gray matter volume. There was also a negative correlation between gray matter volume in right putamen and Z-SAS score in panic subjects. The current study reports a putaminal gray matter volume decrease in panic subjects, which may be related to the clinical severity of panic disorder.     

Volumes of lateral temporal and parietal structures distinguish between healthy aging, mild cognitive impairment, and Alzheimer's disease

Distinguishing amnestic mild cognitive impairment (MCI) from Alzheimer's disease (AD) and healthy aging depends mainly on clinical evaluation, and, ultimately, on investigator's judgment. Clinical evaluation in vivo is based primarily on cognitive assessments. The present study explores the potential of volumetric magnetic resonance imaging of parietal and lateral temporal brain structures to support the diagnosis of AD and to distinguish AD patients from patients with MCI and healthy control subjects (HCS). 52 age-matched HCS, 18 patients with MCI, and 59 patients with probable late onset AD were investigated. Using computational, neuromorphometric procedures gray matter (GM) was automatically parcellated into 28 local regions of interest, the volumes of which were computed. The left hippocampus (sensitivity/specificity: 80.8-90.4%/55.6-86.4%) and the right hippocampus (73.1-90.4%/66.7-84.7%) provided highest diagnostic accuracy in separating all three diagnostic groups. Promising diagnostic values for distinguishing MCI from HCS were found for the left superior parietal gyrus (61.5%/55.6%) and left supramarginal gyrus (65.4%/66.7%), and for distinguishing subjects with MCI from AD patients for the right middle temporal gyrus (77.8%/79.7%), left inferior temporal gyrus (83.3%/72.9%), and right superior temporal gyrus (77.8%/71.2%). The left superior temporal pole (92.3%/84.7%), left parahippocampal gyrus (86.5%/81.4%), left Heschl's gyrus (86.5%/79.7%), and the right superior temporal pole (82.7%/78.0%) revealed most promising diagnostic values for distinguishing AD patients from HCS. Data revealed that lateral temporal and parietal GM volumes distinguish between HCS, MCI, and AD as accurate as hippocampal volumes do; hence, these volumes can be used in the diagnostic procedure. Results also suggest that cognitive functions associated with these brain regions, e.g., language and visuospatial abilities, may be tested more extensively to obtain additional information that might enhance the diagnostic accuracy further.     

首次发病且未用药的成年早发和晚发抑郁症患者脑功能连接差异研究

目的比较成年早发抑郁症(EOD)和成年晚发抑郁症(LOD)患者默认网络(DMN)内部功能连接的差异,探究不同发病年龄的抑郁症患者是否有不同的发病机制。方法选取在昆明医科大学第一附属医院精神科门诊或住院的EOD患者(n=58)和LOD患者(n=62)为研究对象,同期招募年轻健康对照组(n=60)和年老健康对照组(n=52)。对受试者进行静息态功能磁共振扫描,选择左侧楔前叶为种子点,计算该种子点与全脑的功能连接,并比较各组间该种子点的功能连接差异。结果四组之间功能连接具有差异的脑区涉及双侧额叶、颞叶、基底节、枕叶、顶叶及小脑等脑区。EOD组左侧楔前叶与左侧小脑Crus1区、左侧小脑IX区、左侧颞中回、右侧楔前叶、右侧前扣带回、右侧额中回、右侧角回、右侧脑岛、右侧内侧额上回、右侧颞中回的功能连接均高于年轻健康对照组(Z=3. 752 4～5. 867 8,P均0. 05);而左侧楔前叶与左侧额中回、左侧中央旁小叶、右侧缘上回、右侧额上回、右侧颞下回、右侧中央后回、右侧中央前回、右侧枕上回的功能连接均低于年轻健康对照组(Z=-5. 007 6～-3. 797 7,P均0. 05)。LOD组左侧楔前叶与左侧小脑Crus2区、左侧尾状核、左侧颞下回、左侧小脑Crus1区、左侧角回、左侧额中回、右侧额中回、右侧角回、右侧眶额部额中回的功能连接均高于年老健康对照组(Z=4. 122 8～6. 579 4,P均0. 05);与左侧海马旁回、左侧额上回、右侧枕中回、右侧中央前回、右侧内侧额上回、右侧锯状回、右侧颞下回、右侧中央旁小叶、右侧梭状回、右侧后扣带回的功能连接均低于年老健康对照组(Z=-5. 884 0～-3. 617 2,P均0. 05)。EOD组左侧楔前叶与左侧锯状回、左侧小脑IV-VI区、左侧小脑Crus2区的功能连接比LOD组高(Z=4. 087 7、3. 937 4、3. 672 1,P均0. 05);EOD组左侧楔前叶与右侧额中回、右侧眶额部额下回、右侧额上回的功能连接比LOD组低(Z=-4. 274 8、-3. 956 8、-4. 724 3、-3. 663 2,P均0. 05)。结论 DMN内部功能连接增高及额顶网络功能连接降低可能与EOD的发病机制相关,而DMN前部功能连接增高和后部功能连接降低可能与LOD的发病机制相关,不同发病年龄的成年抑郁症患者可能有不同的发病机制。     

3.0T常规磁共振阴性药物难治性颞叶癫痫脑灰质及结构网络研究

目的探讨3.0T常规磁共振阴性的药物难治性颞叶癫痫(rTLE-N)与药物控制性颞叶癫痫(cTLE-N)脑灰质体积及脑白质结构网络拓扑属性差异。方法选取2017年3月至2019年8月在广西医科大学第一附属医院就诊的20例rTLE-N、15例cTLE-N完成头颅3DT1及DTI扫描,20例健康对照(HC)也完成此项检查。基于体素的形态学分析(VBM)方法比较3组脑灰质体积差异,基于图论的方法比较3组脑白质结构网络拓扑属性差异。结果①VBM结果:与HC组相比,rTLE-N组在双侧海马、丘脑、颞中回、内侧和旁扣带回,左侧直回、眶内额上回,右侧海马旁回灰质体积减少(P<0.001);cTLE-N组右侧颞中回、眶内额上回灰质体积减少(P<0.001)。与cTLE-N组相比,rTLE-N组在双侧岛叶、中央沟盖,左侧海马旁回、眶内额上回、梭状回、小脑6区,右侧丘脑、枕下回灰质体积减少(P<0.001);②脑白质结构网络拓扑属性结果:3组脑白质结构网络均表现出小世界属性。与HC组比较,rTLE-N组最短路径长度(Lp)增加、局部效率(Eloc)及全局效率(Eg)下降(P<0.05),cTLE-N组Lp增加、Eg下降(P<0.05);与cTLE-N组比较,rTLE-N组Lp增加、Eloc及Eg下降(P<0.05)。结论TLE-N是一种脑网络疾病,但rTLE-N与cTLE-N致痫网络不同,cTLE-N脑灰质萎缩较局限但已出现脑结构网络拓扑属性受损,而rTLE-N涉及多个脑区灰质萎缩且脑结构网络拓扑属性损害更严重。     

阿尔茨海默病脑白质葡萄糖代谢异常分析

目的探讨阿尔茨海默病(AD)脑白质葡萄糖代谢异常的意义。方法纳入33例符合美国精神障碍诊断与统计手册-第四版(DSM-IV)AD诊断标准的患者和健康对照20名,进行脑正电子发射断层成像(PET)检查。应用SPM软件对PET图像进行分析。结果①与健康对照相比,AD患者有广泛的白质葡萄糖代谢减低,减低较为明显的区域有右侧额叶皮质下白质、左侧额叶上中回皮质下白质(P<0.001);另外,AD患者左侧额叶内侧回皮质下白质、左侧枕叶楔回皮质下白质葡萄糖代谢增强(P<0.001);②与不伴有精神行为症状(BPS)的AD患者(16例)相比,伴有BPS的AD患者(17例)在左右枕叶中回、右侧枕叶楔回、右侧顶下小叶、左侧颞叶梭形回、左侧额叶内侧回等脑区的皮质下白质葡萄糖代谢增强(P<0.001);而左右额叶中央旁回、右侧额叶上回和中回、左侧颞叶上回等脑区的皮质下白质葡萄糖代谢减低(P<0.001)。结论AD有广泛的白质脑葡萄糖代谢异常,有无BPS的AD白质代谢异常不同。     

注意缺陷/多动障碍工作记忆的bold-功能磁共振成像研究

目的应用bold-功能磁共振成像(bold-fMRI)技术来研究注意缺陷/多动障碍(AD/HD)患者的工作记忆。并探讨使用哌醋甲酯1个月治疗前后AD/HD患者的脑部激活的改变情况。方法利用倒数n刺激模式(n-back)对7例AD/HD(注意缺陷为主型)和7名正常人进行blod-fMRI检查,对照研究AD/HD患者在工作记忆时涉及的各脑区的激活情况。结果AD/HD组治疗后的1-back任务较治疗前1-back任务在右额下回和右额中回激活明显,二者有显著性差异(P<0.05);AD/HD组在治疗后的2-back任务较治疗前2-back任务在左额下回和左顶叶后下部激活明显(P<0.05)。正常组的1-back任务与患者组治疗前的1-back任务比较没有显著性差异,正常组的2-back任务与患者组治疗前2-back任务比较在左额下回和左顶叶后下部激活明显(P<0.05)。结论AD/HD障碍患者存在执行功能方面的缺陷,AD/HD患者的语义性工作记忆缺损可能与前额叶和顶叶的功能缺陷有关。     

Three subsystems of the inferior parietal cortex are differently affected in mild cognitive impairment

The Inferior parietal cortex (IPC), including the intraparietal sulcus (IPS), angular gyrus (AG), and supramarginal gyrus (SG), plays an important role in episodic memory, and is considered to be one of the specific neuroimaging markers in predicting the conversion of mild cognitive impairment (MCI) to Alzheimer's disease (AD). However, it is still unclear whether the connectivity of the IPC is impaired in MCI patients. In the present study, we used resting state fMRI to examine the functional connectivity of the three subdivisions of the IPC in MCI patients after controlling the impact of regional grey matter atrophy. It was found that, using IPS, AG, and SG as seeds of functional connectivity, three canonical functional networks could be correspondingly traced, i.e., executive control network (ECN), default mode network (DMN), and salience network (SN), and the three networks are differently altered in MCI patients. In contrast to the healthy controls, it was found that in MCI patients: 1) AG connectivity was significantly reduced within the DMN; 2) IPS showed decreased connectivity with the right inferior frontal gyrus while showing increased connectivity with the left frontal regions within the ECN; and 3) SG displayed decreased connectivity with a distribution of regions including the frontal and parietal regions, and increased connectivity with some sub-cortical areas within the SN. Moreover, the connectivity within the three networks was correlated with episodic memory and general cognitive impairment in MCI patients. These results extend well beyond the DMN, and further suggest that MCI is associated with alteration of large-scale functional brain networks.     

反社会人格障碍男性青年大脑白质异常改变： 证据来自于基于体素脑形态测量学的DARTEL分析

SPM8 DARTEL工具包对3D脑结构成像数据对男性青年反社会人格障碍者和正常组的大脑白质结构进行基于体素的形态学分析（VBM）。结果显示,与正常对照者比较,反社会人格障碍者主要表现为双侧前额叶、右岛叶、中央前回,左右颞上回、右中央后回、右侧顶下小叶、右侧楔前叶、右枕中叶、右海马旁回及双侧扣带回等多个脑区白质体积密度增加,左颞中叶、右小脑的白质体积密度减小。相关分析显示,额内侧回的白质体积密度增加与反社会行为的评分(PDQ)有正相关。提示反社会人格障碍者存在多个脑区的白质形态学明显异常,这些异常可能与其反社会行为有关。