抑郁症首次发病患者静息态脑功能局部一致性的研究

目的 利用功能磁共振(fMRI)和局部一致性(regional homogeneity,ReHo)探讨抑郁症首次发病(以下简称首发)患者在静息态脑功能是否存在异常及异常部位.方法 对34例符合美国精神疾病诊断与统计手册第4版诊断标准的首发抑郁症患者(抑郁症组)和34名性别、年龄、文化程度匹配的健康志愿者(对照组)进行静息态fMRI扫描.结果 抑郁症组静息态脑血氧水平依赖信号的ReHo高于对照组的脑区有左侧额叶眶回、顶下小叶、颞上回,右侧额内侧回、顶下小叶、小脑后叶;低于对照组的脑区有左颞下回、右颞上同和胼胝体、双侧后扣带回(P＜0.005,K≥10).结论首发抑郁症患者在静息态存在多个腩区功能活动的异常,并可能和抑郁症的病理机制有关.     

抑郁症患者静息状态的功能磁共振成像研究

目的 了解在静息状态下抑郁症患者脑区的局部一致性特点.方法 采用功能磁共振成像(fMRI)技术,检测静息状态下27例抑郁症患者(患者组)和性别、年龄、受教育程度均与患者相匹配的27名正常人(对照组)的脑功能活动,并对两组进行比较.利用局部一致性方法 分析fMRI数据,用SPM2软件进行配对t检验(P＜0.005).结果 与对照组相比,患者组双侧额中回、右额下回、右颞上回、左前扣带回、右后扣带回、右岛叶、双侧豆状核、双侧屏状核、左尾状核局部一致性显著增高(P＜0.005,未校正,体素值＞10);未显示脑区有明显的局部一致性减低.结论 抑郁症患者神经环路脑区局部在静息状态下具有很高的一致性,其局部一致性的增高可能参与了抑郁症的代偿机制.     

重性抑郁症基于低频振幅的静息态功能磁共振成像研究

目的观察重性抑郁症患者静息态fMRI(rs-fMRI)特点,并探讨其可能发病机制。方法采用基于低频振幅(ALFF)的rs-f MRI对24例重性抑郁症患者和性别、年龄、受教育程度匹配的26例正常对照者进行比较,Spearman秩相关分析探讨各脑区mALFF值与汉密尔顿抑郁量表17项(HAMD-17)评分的相关性。结果与正常对照者相比,重性抑郁症患者双侧背外侧前额叶皮质、右侧眶部额上回、右侧颞下回、左侧岛盖部额下回、左侧内侧额上回、左侧直回mALFF值升高(均P0.05,AlphaSim校正),双侧补充运动区、右侧后扣带回、右侧楔前叶、左侧舌回mALFF值降低(均P0.05,AlphaSim校正)。Spearman秩相关分析显示,重性抑郁症患者各脑区mALFF值与HAMD-17评分无关联性(均P0.05)。结论重性抑郁症患者静息态下神经功能损害主要集中于脑默认网络和边缘系统等多个脑区,提示其可能存在特征性神经功能改变基础。     

腰背痛患者静息态fMRI的脑功能局部一致性研究

目的 利用功能磁共振成像(fMRI)技术探讨静息状态下腰背痛患者脑局部一致性(ReHo)变化的特点. 方法 选择自2011年8月至2012年1月南方医科大学珠江医院康复医学科招募的15例年龄、性别和文化程度相近的健康者作为受试者,向其右侧腰背部肌肉注射0.3 mL30g/L的高渗盐水制造腰背痛模型,采用3.0T MR仪分别在注射前、注射后进行静息状态fMRI扫描,所得数据进行配对t检验,比较疼痛及非疼痛状态下静息态脑功能的局部一致性差异. 结果 与正常状态相比,腰背痛受试者ReHo增高的脑区有:双侧前额叶内侧、左额下回、右额中回、右小脑扁桃体、右脑桥、右岛叶、右尾状核、右楔前叶、右海马旁回、后扣带回;ReHo减低的脑区有:右颞上回、左颞中回、左中央前回、左中央后回、左海马旁回、左梭状回、左前扣带回、左顶上小叶、右顶下小叶(P＜0.005,体素值≥10). 结论 静息状态下腰背痛患者部分脑区存在脑活动区域一致性异常.     

健康人倒背数字作业的脑功能磁共振成像研究

目的　利用功能磁共振成像(functionalmagneticresonanceimaging ,fMRI)技术探讨倒背数字作业认知功能的脑功能定位。方法　1 8名健康志愿者完成以倒背数字作业(backwarddigitspantask ,BDST)作为刺激模式、采用组块设计(block)的fMRI检查,经工作站处理后获功能图像。结果　健康志愿者的左侧额上回、额中回、额下回、中央前回、顶上小叶、缘上回、颞下回、枕颞外侧回及右侧额中回等脑区均有明显激活。结论　左侧额叶腹外侧及左侧项叶后下部可能参与工作记忆对语言材料激活信息的保持,而双侧额叶背外侧可能参与工作记忆对语言材料激活信息的执行控制。     

部分性发作癫痫患者静息状态功能磁共振默认模式网络的功能连接改变

目的 应用静息状态功能磁共振成像(fMRI)探讨部分性发作癫痫患者静息状态下的脑功能改变.方法 对60例部分性发作癫痫患者(患者组)和60名性别、年龄和教育程度匹配的健康对照者(对照组),使用3.0T磁共振采集两组的静息状态下fMRI数据,采用功能连接方法分析计算脑区的默认模式网络的功能连接,利用SPM5软件分析比较患者组和对照组脑功能的差异.结果 患者组的默认模式网络的功能连接主要包括左侧楔前叶/后扣带回和角回、扣带回;对照组的功能连接主要包括左侧楔前叶/后扣带回和右侧角回,双侧内侧额叶和颞叶;患者组的左侧顶下小叶[坐标值(x,y,z):-57,-39,48;t=4.90,P＜0.01]、左侧缘上回[坐标值(x,y,z):-63,- 48,33;t=4.25,P＜0.01]、左侧海马旁回[坐标值(x,y,z):-30,-6,-21;t =4.05,P＜0.01]、左侧颞上回[坐标值(x,y,z):-48,-39,6;t=3.72,P＜0.01],左侧钩回[坐标值(x,y,z):-24,6,- 36;=4.56,P＜0.01]及右侧钩回[坐标值(x,y,z):33,-15,- 36;t=4.00,P＜0.01]的默认模式网络功能连接较对照组降低;未发现功能连接升高的脑区.结论 部分性发作癫痫患者静息状态下脑区的功能连接改变,可能是部分性发作癫痫潜在的病理生理机制.静息状态fMRI能发现常规MRI正常的癫痫患者的广泛脑功能异常,是一种无创的研究癫痫患者脑功能的有效方法.     

正常人词语流畅性作业的脑功能磁共振成像研究

目的 利用功能磁共振成像(fMRI)技术探讨词语流畅性作业的脑功能定位。方法对18名健康志愿者进行词语流畅性作业的fMRI检查,fMRI用梯度回波-平面回波成像序列采集数据,经工作站处理后获功能图像。结果 经Fisher精确检验法,健康志愿者的双侧额上回、双侧额中回、右侧额下回及右侧扣带回的激活脑区计数,与理想激活脑区计数的差异均无显著性(P>0.05),其余脑区激活计数的差异均有显著性(P<0.05)。结论 双侧额叶背外侧及右侧额叶腹外侧可能参与长时记忆的提取过程,其中额叶背外侧可能参与核查及管理工作,而额叶腹外侧可能参与搜寻特异目标的过程。     

基于功能磁共振成像的早发精神分裂症默认网络研究

目的：探讨早发精神分裂患者在静息状态下脑默认网络功能连接特点。方法：采用功能磁共振成像（fMRI）技术,对26例早发精神分裂症患者和28例正常对照进行静息状态下全脑的磁共振脑功能扫描。采用功能连接分析方法,提取静息状态下默认网络,在患者组和对照组中分别计算默认网络各脑区两两间的功能连接。结果：早发精神分裂症组在默认网络存在5条异常连接。其中3条连接表现为连接增强：腹侧前额叶内侧皮质-右侧颞下回（P=0.0078）,腹侧前额叶内侧皮质-左侧外侧顶叶（P=0.0091）、腹侧前额叶内侧皮质-背侧前额叶内侧皮质（P=0.0163）。2条连接表现为连接减弱：右侧外侧顶叶-小脑扁桃体（P=0.0223）,左侧额上回-右侧下半月小叶（P=0.0294）。结论：早发精神分裂症患者存在默认网络功能的异常。这些异常改变可能与精神分裂症的病理机制相关。     

颞叶癫痫患者执行功能的功能磁共振研究

目的 探讨颞叶癫痫(temporal lobe epilepsy ,TLE)患者执行功能的脑功能状态及激活模式.方法 应用注意网络测试(attentional networks test,ANT)软件,对12例TLE患者及12名健康受试者进行执行功能行为学测试;应用组块式功能磁共振(functional magnetic resonance imaging ,fMRI)扫描,使用统计参数图(Statistical Parametric Mapping 2,SPM 2)软件分析fMRI数据.结果 与健康受试组比较,TLE患者组执行功能反应时间(RT)较慢[患者组:(158.9±50.2)ms;健康受试组:(112.4±28.3)ms, t=2.63,P<0.05].健康受试组执行功能fMRI显示激活脑区右侧半球偏侧化,位于右扣带回后部、颞下回、前额叶、海马、顶叶及左颞中回.TLE患者组右侧前额叶和右额叶 (激活体素:53,34 voxel P<0.01)等靠近中线脑区激活体素较小.健康受试组存在与反应时间正、负相关脑区(P<0.001),TLE组则仅存与反应时间正相关脑区(P<0.001).结论 TLE患者存在执行功能障碍,与上述脑区激活功能低下和失调控有关,这些脑区可能是TLE患者执行功能损害的形态学基础.     

青少年广泛性焦虑障碍患者静息态功能磁共振成像研究

目的:运用局部一致性(ReHo)方法研究首发青少年广泛性焦虑障碍患者的局部自发性脑活动. 方法:对19例首发青少年广泛性焦虑障碍患者及14名年龄、性别与其相匹配的正常对照进行静息态脑功能磁共振成像扫描,通过计算每个给定体素与其最邻近的26个体素之间的肯德尔和谐系数(KCC)来获得全脑的局部一致性(ReHo)图,利用双样本t检验分析两组受试者静息态下局部一致性的差异. 结果:与正常对照相比,青少年广泛性焦虑障碍患者局部一致性降低的脑区包括双侧额中回、枕中回,左侧额上回、颞下回、前扣带回及右侧顶下回、枕下回(P ＜0.005,未校正);局部一致性增高的脑区包括:右侧楔前叶、角回及左侧枕上回(P ＜0.005,未校正). 结论:青少年广泛性焦虑障碍患者静息态脑功能局部一致性存在异常.     

Altered default mode network connectivity in Alzheimer's disease--a resting functional MRI and Bayesian network study

A number of functional magnetic resonance imaging (fMRI) studies reported the existence of default mode network (DMN) and its disruption due to the presence of a disease such as Alzheimer's disease (AD). In this investigation, first, we used the independent component analysis (ICA) technique to confirm the DMN difference between patients with AD and normal control (NC) reported in previous studies. Consistent with the previous studies, the decreased resting-state functional connectivity of DMN in AD was identified in posterior cingulated cortex (PCC), medial prefrontal cortex (MPFC), inferior parietal cortex (IPC), inferior temporal cortex (ITC), and hippocampus (HC). Moreover, we introduced Bayesian network (BN) to study the effective connectivity of DMN and the difference between AD and NC. When compared the DMN effective connectivity in AD with the one in NC using a nonparametric random permutation test, we found that connections from left HC to left IPC, left ITC to right HC, right HC to left IPC, to MPFC and to PCC were all lost. In addition, in AD group, the connection directions between right HC and left HC, between left HC and left ITC, and between right IPC and right ITC were opposite to those in NC group. The connections of right HC to other regions, except left HC, within the BN were all statistically in-distinguishable from 0, suggesting an increased right hippocampal pathological and functional burden in AD. The altered effective connectivity in patients with AD may reveal more characteristics of the disease and may serve as a potential biomarker.     

Detection of PCC functional connectivity characteristics in resting-state fMRI in mild Alzheimer's disease

Resting-state networks dissociate in the early stage of Alzheimer's disease (AD). The posterior cingulate cortex (PCC) in AD brain is vulnerable to isolation from the rest of brain. However, it remains unclear how this functional connectivity is related to PCC changes. We employed resting-state functional MRI (fMRI) to examine brain regions with a functional connection to PCC in a mild AD group compared with matched control subjects. PCC connectivity was gathered by investigating synchronic low frequency fMRI signal fluctuations with a temporal correlation method. We found asymmetric PCC-left hippocampus, right dorsal-lateral prefrontal cortex and right thalamus connectivity disruption. In addition, some other regions such as the bilateral visual cortex, the infero-temporal cortex, the posterior orbital frontal cortex, the ventral medial prefrontal cortex and the precuneus showed decreased functional connectivity to the PCC. There were also some regions, primarily in the left frontal-parietal cortices, that showed increased connectivity. These regions included the medial prefrontal cortex, bilateral dorsal-lateral prefrontal cortex, the left basal ganglia and the left primary motor cortex. Impairments to memory, high vision-related functions and olfaction in AD can be explained by a disruption to the functional connection of resting-state networks. The results of increased connectivity may support the compensatory-recruitment hypothesis. Our findings suggest that the characteristics of resting-state functional connectivity could plausibly provide an early imaging biomarker for AD.     

Medial prefrontal functional connectivity--relation to memory self-appraisal accuracy in older adults with and without memory disorders

It is tentatively estimated that 25% of people with early Alzheimer's disease (AD) show impaired awareness of disease-related changes in their own cognition. Research examining both normative self-awareness and altered awareness resulting from brain disease or injury points to the central role of the medial prefrontal cortex (MPFC) in generating accurate self-appraisals. The current project builds on this work - examining changes in MPFC functional connectivity that correspond to impaired self-appraisal accuracy early in the AD time course. Our behavioral focus was self-appraisal accuracy for everyday memory function, and this was measured using the Memory Function Scale of the Memory Awareness Rating Scale - an instrument psychometrically validated for this purpose. Using regression analysis of data from people with healthy memory (n=12) and people with impaired memory due to amnestic mild cognitive impairment or early AD (n=12), we tested the hypothesis that altered MPFC functional connectivity - particularly with other cortical midline structures and dorsolateral prefrontal cortex - explains variation in memory self-appraisal accuracy. We spatially constrained (i.e., explicitly masked) our regression analyses to those regions that work in conjunction with the MPFC to evoke self-appraisals in a normative group. This empirically derived explicit mask was generated from the result of a psychophysiological interaction analysis of fMRI self-appraisal task data in a separate, large group of cognitively healthy individuals. Results of our primary analysis (i.e., the regression of memory self-appraisal accuracy on MPFC functional connectivity) were generally consistent with our hypothesis: people who were less accurate in making memory self-appraisals showed attenuated functional connectivity between the MPFC seed region and proximal areas within the MPFC (including subgenual anterior cingulate cortex), bilateral dorsolateral prefrontal cortex, bilateral caudate, and left posterior hippocampus. Contrary to our expectations, MPFC functional connectivity with the posterior cingulate was not significantly related to accuracy of memory self-appraisals. Results reported here corroborate findings of variable memory self-appraisal accuracy during the earliest emergence of AD symptoms and reveal alterations in MPFC functional connectivity that correspond to impaired memory self-appraisal.     

长期海洛因成瘾者前额叶功能连接的静息态fMRI研究

目的 利用静息态fMRI探讨长期海洛因成瘾者前额叶功能连接的变化情况.方法 13例长期海洛因成瘾者和14例正常者接受静息态fMRI检查,对数据进行相关的预处理后,以前额叶为种子点与全脑每个体素进行相关分析,比较海洛因成瘾组与正常对照组前额叶功能连接的变化情况.结果 以左侧前额叶为种子点进行功能连接分析,海洛因成瘾组左侧前额叶与左侧海马、右侧前扣带回、左侧额中回、右侧额中回、右侧楔前叶功能连接明显低于正常对照组:以右侧前额叶为种子点进行功能连接分析,海洛因成瘾组右侧前额叶与左侧眶额叶、左侧额中回功能连接明显低于正常对照组.结论 长期海洛因成瘾者前额叶与相关脑区的功能连接减弱,前额叶可能参与了海洛因成瘾的维持与戒断后复吸.

Abstract：

Objective To explore the changes of functional connectivity of the prefrontal cortex in chronic heroin addicts under resting-state functional MRI (fMRI). Methods Resting fMRI examination was performed on 13 chronic heroin addicts and 14 healthy volunteers. After pre-processing the resting-state fMRI data, the prefrontal cortex was selected as the seed region, with which a whole-brain voxel temporal correlation in Iow frequency fMRI fluctuations was analyzed and the changes of functional connectivity of the prefrontal lobe in both chronic heroin addicts and healthy volunteers were calculated with SPM5 software. Results Compared with that in the control group, the functional connectivity between the left prefrontal cortex and the left hippocampus, right anterior cingulate, left middle frontal gyrus, right middle frontal gyrus, right precuneus in the heroin addiction group was significantly decreased. The functional connectivity between the right prefrontal cortex and the left orbital frontal cortex, left middle frontal gyrus in thc heroin addiction group was also significantly decreased as compared with that in the control group. Conclusion Functional connectivity of prefrontal cortex in chronic heroin addicts decreases, indicating that the prefrontal cortex may be involved in the maintenance of heroin addiction and relapse after withdrawal.     

Intrinsic brain abnormalities in irritable bowel syndrome and effect of anxiety and depression

This resting-state functional magnetic resonance imaging (rs-fMRI) study investigated intrinsic brain abnormalities in irritable bowel syndrome (IBS) and effect of anxiety and depression. Thirty IBS patients and 31 matched healthy controls underwent rs-fMRI scanning. Regional brain activity was evaluated by measuring the amplitude of low-frequency fluctuation (ALFF) and compared between IBS patients and healthy controls with a two-sample t-test. Areas with abnormal ALFF were further used as seeds in subsequent inter-regional functional connectivity (FC) analysis. Statistical analyses were also performed by including anxiety and depression as covariates to evaluate their effect. Compared to healthy controls, IBS patients showed decreased ALFF in several core default mode network regions (medial prefrontal cortex [MPFC], posterior cingulate cortex [PCC], bilateral inferior parietal cortices [IPC]), and in middle frontal cortex, right orbital part of the superior frontal gyrus (ORBsup), dorsal anterior cingulate cortex (dACC), and ventral anterior cingulated cortex (vACC), while they showed increased ALFF in bilateral posterior insula and cuneus. In addition, IBS patients revealed decreased inter-regional positive FC between MPFC and right ORBsup, between vACC and PCC, as well as decreased negative FC between MPFC and left posterior insula, while they showed increased negative FC between MPFC and cuneus. The inclusion of anxiety and depression as covariates abolished ALFF differences in dACC and vACC, but none of the FC differences. In conclusion: IBS patients had disturbed intrinsic brain function. High levels of anxiety and depression in IBS patients could account for their decreased intrinsic brain activity in regions (the ACC) involved in affective processing.     

Short Term Exposure to a Violent Video Game Induces Changes in Frontolimbic Circuitry in Adolescents

Despite evidence of effects of violent video game play on behavior, the underlying neuronal mechanisms involved in these effects remain poorly understood. We report a functional MRI (fMRI) study during two modified Stroop tasks performed immediately after playing a violent or nonviolent video game. Compared with the violent video game group, the nonviolent video game group demonstrated more activation in some regions of the prefrontal cortex during the Counting Stroop task. In contrast to the violent video game group, significantly stronger functional connectivity between left dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) was identified in the nonviolent video game group. During an Emotional Stroop task, the violent video game group showed more activity in the right amygdala and less activation in regions of the medial prefrontal cortex (MPFC). Furthermore, functional connectivity analysis revealed the negative coupling between right amygdala and MPFC in the nonviolent video game group. By contrast, no significant functional connectivity between right amygdala and MPFC was found in the violent video game group. These results suggest differential engagement of neural circuitry in response to short term exposure to a violent video game as compared to a nonviolent video game.     

Disrupted functional connectivity for controlled visual processing as a basis for impaired spatial working memory in schizophrenia

Although regional brain abnormalities underlying spatial working memory (SWM) deficits in schizophrenia have been identified, little is known about which brain circuits are functionally disrupted in the SWM network in schizophrenia. We investigated SWM-related interregional functional connectivity in schizophrenia using functional magnetic resonance imaging (fMRI) data collected during a memory task that required analysis of spatial information in object structure. Twelve schizophrenia patients and 11 normal control subjects participated. Patients had SWM performance deficits and deficient neural activation in various brain areas, especially in the high SWM load condition. Examination of the covariation of regional brain activations elicited by the SWM task revealed evidence of functional disconnection between prefrontal and posterior visual association areas in schizophrenia. Under low SMW load, we found reduced functional associations between dorsolateral prefrontal cortex (DLPFC) and inferior temporal cortex (ITC) in the right hemisphere in patients. Under high SWM load, we found evidence for further functional disconnection in patients, including additional reduced functional associations between left DLPFC and right visual areas, including the posterior parietal cortex (PPC), fusiform gyrus, and V1, as well as between right inferior frontal cortex and right PPC. Greater prefrontal-posterior cortical functional connectivity was associated with better SWM performance in controls, but not in patients. These results suggest that prefrontal-posterior functional connectivity associated with the maintenance and control of visual information is central to SWM, and that disruption of this functional network underlies SWM deficits in schizophrenia.     

Altered resting-state functional connectivity of the cerebellum in schizophrenia

Structural and functional abnormalities of the cerebellum in schizophrenia have been reported. Most previous studies investigating resting-state functional connectivity (rsFC) have relied on a priori restrictions on seed regions or specific networks, which may bias observations. In this study, we aimed to elicit the connectivity alterations of the cerebellum in schizophrenia in a hypothesis-free approach. Ninety-five schizophrenia patients and 93 sex- and age-matched healthy controls underwent resting-state functional magnetic resonance imaging (fMRI). A voxel-wise data-driven method, resting-state functional connectivity density (rsFCD), was used to investigate cerebellar connectivity changes in schizophrenia patients. Regions with altered rsFCD were chosen as seeds to perform seed-based resting-state functional connectivity (rsFC) analyses. We found that schizophrenia patients exhibited decreased rsFCD in the right hemispheric VI; moreover, this cerebellar region showed increased rsFC with the prefrontal cortex and subcortical nuclei and decreased rsFC with the visual cortex and sensorimotor cortex. In addition, some rsFC changes were associated with positive symptoms. These findings suggest that abnormalities of the cerebellar hub and cerebellar-subcortical-cortical loop may be the underlying mechanisms of schizophrenia.     

Prefrontal transcranial direct current stimulation changes connectivity of resting-state networks during fMRI

Transcranial direct current stimulation (tDCS) has been proposed for experimental and therapeutic modulation of regional brain function. Specifically, anodal tDCS of the dorsolateral prefrontal cortex (DLPFC) together with cathodal tDCS of the supraorbital region have been associated with improvement of cognition and mood, and have been suggested for the treatment of several neurological and psychiatric disorders. Although modeled mathematically, the distribution, direction, and extent of tDCS-mediated effects on brain physiology are not well understood. The current study investigates whether tDCS of the human prefrontal cortex modulates resting-state network (RSN) connectivity measured by functional magnetic resonance imaging (fMRI). Thirteen healthy subjects underwent real and sham tDCS in random order on separate days. tDCS was applied for 20 min at 2 mA with the anode positioned over the left DLPFC and the cathode over the right supraorbital region. Patterns of resting-state brain connectivity were assessed before and after tDCS with 3 T fMRI, and changes were analyzed for relevant networks related to the stimulation-electrode localizations. At baseline, four RSNs were detected, corresponding to the default mode network (DMN), the left and right frontal-parietal networks (FPNs) and the self-referential network. After real tDCS and compared with sham tDCS, significant changes of regional brain connectivity were found for the DMN and the FPNs both close to the primary stimulation site and in connected brain regions. These findings show that prefrontal tDCS modulates resting-state functional connectivity in distinct functional networks of the human brain.     

Prefrontal Brain Network Connectivity Indicates Degree of Both Schizophrenia Risk and Cognitive Dysfunction

Objective:

Cognitive dysfunction is a core feature of schizophrenia, and persons at risk for schizophrenia may show subtle deficits in attention and working memory. In this study, we investigated the relationship between integrity of functional brain networks and performance in attention and working memory tasks as well as schizophrenia risk.

Methods:

A total of 235 adults representing 3 levels of risk (102 outpatients with schizophrenia, 70 unaffected first-degree relatives of persons with schizophrenia, and 63 unrelated healthy controls [HCs]) completed resting-state functional magnetic resonance imaging and a battery of attention and working memory tasks (Brief Test of Attention, Hopkins Verbal Learning Test, and Brief Visuospatial Memory Test) on the same day. Functional networks were defined based on coupling with seeds in the dorsal anterior cingulate cortex, dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and primary visual cortex. Networks were then dissected into regional clusters of connectivity that were used to generate individual interaction matrices representing functional connectivity within each network.

Results:

Both patients with schizophrenia and their first-degree relatives showed cognitive dysfunction compared with HCs. First canonicals indicated an inverse relationship between cognitive performance and connectivity within the DLPFC and MPFC networks. Multivariate analysis of variance revealed multivariate main effects of higher schizophrenia risk status on increased connectivity within the DLPFC and MPFC networks.

Conclusions:

These data suggest that excessive connectivity within brain networks coupled to the DLPFC and MPFC, respectively, accompany cognitive deficits in persons at risk for schizophrenia. This might reflect compensatory reactions in neural systems required for cognitive processing of attention and working memory tasks to brain changes associated with schizophrenia.Key words: resting state, fMRI, default-mode network, attention, working memory