抑郁症的注意网络功能研究

目的研究抑郁症的注意网络状况及其与临床症状的相互关系,以探索抑郁症注意缺陷特征及可能机制。方法对40例抑郁症患者(抑郁组)进行注意网络测定(ANT)和抑郁自评量表(SDS)及汉密顿抑郁量表(HAMD)的临床症状评定,并与正常对照组(n=40)ANT结果比较。结果抑郁组的警觉网络和执行控制网络效率较正常组有显著差异,定向网络效率无差异。抑郁症患者的年龄与平均反应时间呈正相关,与警觉网络效率呈负相关;警觉网络效率与HAMD得分及其睡眠障碍因子分呈负相关;执行控制网络效率与睡眠障碍因子分呈正相关。结论抑郁症患者存在警觉和执行控制注意网络的异常而定向网络保留正常,注意功能的异常与睡眠障碍相关。     

重症肌无力患者的注意网络功能研究

目的探讨重症肌无力(myasthenia gravis,MG)患者注意功能是否受损及其受损特点,并进一步分析其影响因素,对MG注意缺陷的可能神经机制进行推测。方法选取安徽医科大学第一附属医院门诊及住院的MG确诊患者26例,并选取来自同期健康体检中的健康查体者40名作为对照。比较两组简易精神状态检查量表(mini-mental state examination,MMSE)评分、数字广度(digit span,DS)、词语流畅性(verbal fluency test,VFT)、抑郁自测量表(self-rating depression scale,SDS)评分差异,采用注意网络测验(attention network test,ANT)方法对受试者的注意功能受损情况进行检测。结果 MG和对照组间MMSE、DS、VFT、SDS评分差异无统计学意义(均P0.05);两组间ANT总平均反应时间(RT)及总平均正确率差异无统计学意义(均P0.05);MG组的定向网络效率与对照组比较减低(t=-4.198,P0.01),而两组间警觉网络与执行网络差异比较无统计学意义(均P0.05)。结论 MG患者存在注意功能损害,表现为定向网络异常,而警觉网络与执行控制网络保留正常,提示患者可能存在中枢胆碱能系统损害,推测MG患者存在认知功能障碍。     

青少年反社会人格高危群体注意网络功能研究

目的:探讨青少年反社会人格障碍高危群体注意网络功能特点。方法:选取1 135名少年犯,根据人格诊断问卷和美国《精神障碍诊断与统计手册》(DSM-IV)结构式访谈,筛选出50例,将其分为反社会人格障碍高危(CD+AP)组(n=26)和品行障碍(CD)组(n=24),采用注意网络测验(ANT)评估其注意警示、定向和执行功能特点,并与健康志愿者(健康对照组,n=30)比较。结果:CD+AP组的注意定向效能[(37.02±15.72)ms]显著低于CD组[(44.34±15.41)ms](P<0.01),却显著强于健康对照组[(31.29±12.16)ms](P<0.05);CD+AP组注意执行功能[(65.83±19.55)ms]显著强于健康对照组[(77.59±14.49)ms](P<0.05)。结论:青少年反社会人格高危群体的注意定向功能和执行功能异常增强,这可能与反社会行为的发生密切相关。     

颞叶癫痫患者注意网络的研究

目的探讨颞叶癫痫患者注意网络的状况及影响因素。方法连续收录2007年1月至2008年12月在我院就诊的44例颞叶癫痫患者,选择相匹配的健康志愿者40名作为对照研究。应用注意网络测试(attentional networks test,ANT)软件,评估被试者注意网络状况,比较两组注意网络各指标的差异,采用非条件Logistic分析受教育年限、病程等因素对注意网络指标的影响。结果与对照组比较,患者组的ANT平均反应时间较慢[患者组:(688.2±138.1)ms;对照组:(625.1±100.1)ms,t=2.06,P0.05];患者组ANT中执行功能效率显著下降[患者组:(155.7±57.0)ms;对照组:(108.0±33.8)ms,t=4.62,P0.01];两组MMSE、ANT的警觉功能与定向功能效率无统计学差异。非条件Logistic分析显示,存在脑电图痫性放电(95%CI:1.03～42.33,OR=6.603,P=0.043)为患者执行功能损害可能原因。结论初步证实颞叶癫痫患者存在注意网络的执行功能损害,痫性放电可能是导致患者注意执行功能损害的原因。     

不同手机依赖程度者注意网络功能的特点

目的 探讨不同手机依赖程度的人群注意功能特征及可能机制。方法 使用手机成瘾指数量表（MPAI）筛选志愿者,分为高、低手机依赖组各27人,采用注意网络测试比较两组研究对象注意网络功能的差异。结果 高手机依赖组执行控制网络时间（102.96±19.15）ms较低手机依赖组（89.85±21.57）ms明显延长（t=2.363,P=0.022）,且MPAI评分与执行功能网络效率呈正相关（r=0.463,P＜0.01）。两组在警觉、定向网络效率上差异无统计学意义。结论 高手机依赖者较低手机依赖者执行控制能力差,且下降程度与手机依赖程度相关。     

帕金森病患者注意网络的研究

目的 探讨帕金森病(PD)患者注意网络状况.方法 运用注意网络测试,对确诊的PD患者(28例)和对照组(28名)进行注意网络检查.结果 PD组注意网络检查正确率(98.4%±0.3%)低于对照组(99.2%±0.2%),差异有统计学意义(U=261.500,Z=-2.160,P＜0.05).PD组的定向网络效率显著高于对照组[分别为(65.7±31.1)ms,(43.5±32.3)ms],差异有统计学意义(U=226.00,Z=-2.720,P＜0.01).PD组的执行控制网络、警觉网络效率[(97.4±63.1)ms,(35.0±41.0)ms]与对照组比较有改变,但差异无统计学意义(Z=-1.065、Z=-1.082,P＞0.05).相关性分析发现,执行网络功能和Hoehn-Yahr分级呈正相关(r=0.794,P＜0.01),警觉网络与Hoehn-Yahr分级呈负相关(r=-0.379,P=0.047),定向网络与其无相关性(r=-0.119,P=0.546).结论 PD患者存在定向网络的损害,警觉和执行控制注意网络随病程进展而损害加重,提示神经解剖结构和神经递质可能和不同注意网络有关.     

注意缺陷多动障碍的功能神经成像研究

本文就功能神经成像技术如PET、SPECT、fMRI对注意缺陷多动障碍患者的大脑代谢和局部脑血流及神经生化的研究进行综述，结果提示ADHD所涉及的脑区为前额叶、顶叶、颞叶、扣带回，纹状体，基底节等区域。另外也表明注意缺陷障碍的成人的功能神经影像方面不同于儿童。     

注意缺陷多动障碍的功能神经成像研究

本文就功能神经成像技术如PET、SPECT、fMRI对注意缺陷多动障碍患者的大脑代谢和局部脑血流及神经生化的研究进行综述 ,结果提示ADHD所涉及的脑区为前额叶、顶叶、颞叶、扣带回 ,纹状体 ,基底节等区域。另外也表明注意缺陷障碍的成人的功能神经影像方面不同于儿童。     

Deficient prefrontal attentional control in late-life generalized anxiety disorder: an fMRI investigation

Younger adults with anxiety disorders are known to show an attentional bias toward negative information. Little is known regarding the role of biased attention in anxious older adults, and even less is known about the neural substrates of any such bias. Functional magnetic resonance imaging (fMRI) was used to assess the mechanisms of attentional bias in late life by contrasting predictions of a top-down model emphasizing deficient prefrontal cortex (PFC) control and a bottom-up model emphasizing amygdalar hyperreactivity. In all, 16 older generalized anxiety disorder (GAD) patients (mean age=66 years) and 12 non-anxious controls (NACs; mean age=67 years) completed the emotional Stroop task to assess selective attention to negative words. Task-related fMRI data were concurrently acquired. Consistent with hypotheses, GAD participants were slower to identify the color of negative words relative to neutral, whereas NACs showed the opposite bias, responding more quickly to negative words. During negative words (in comparison with neutral), the NAC group showed PFC activations, coupled with deactivation of task-irrelevant emotional processing regions such as the amygdala and hippocampus. By contrast, GAD participants showed PFC decreases during negative words and no differences in amygdalar activity across word types. Across all participants, greater attentional bias toward negative words was correlated with decreased PFC recruitment. A significant positive correlation between attentional bias and amygdala activation was also present, but this relationship was mediated by PFC activity. These results are consistent with reduced prefrontal attentional control in late-life GAD. Strategies to enhance top-down attentional control may be particularly relevant in late-life GAD treatment.     

Alterations of the attentional networks in patients with anxiety disorders

Cognitive theories of emotion try to explain how anxious people attend to the world. Despite the increase in empirical research in this field, the specific or general attentional impairments of patients with anxiety disorder is not well defined. We decided to investigate the relationship between pathological anxiety and attentional mechanisms from the broader perspective of the attentional networks. In our study, patients with anxiety disorders and control participants carried out a task to assess efficiency of three attentional networks: orienting, alerting, and executive control. The main result was that anxiety disorders are related to both reduced effectiveness of the executive control network and difficulties in disengaging attention from invalid cues, even when using emotionally neutral information. This relationship between these attentional networks and anxiety may in part explain the problems in the day-to-day functioning of these patients.     

Gray matter volume covariance networks associated with social networks in older adults

ABSTRACT

Extensive social networks are associated with better physical, mental, and cognitive health in aging, but the underlying brain substrates remain largely unexplored. Voxel-based morphometry and multivariate statistics were used to identify gray matter volume covariance networks associated with social networks in 86 older adults without dementia (M Age = 75.20 years, 53% women). Gray matter networks associated with the number of high-contact social roles and the total number of network members were identified after adjusting for age, sex, education, global health, and total intracranial volume – and shared nodes included medial, lateral and orbital prefrontal, hippocampal, precuneus, insular, and cingulate regions. Greater expression of these gray matter networks was associated with better memory scores on the Free and Cued Selective Reminding Test. A more distributed network was associated with high-contact social roles than total number of networks members – also extending into amygdala and entorhinal cortex. Thus, high-contact social roles and total number of network members in older adults are associated with gray matter networks composed of regions previously linked to memory and affected by both healthy aging and Alzheimer disease – and high-contact social roles are more strongly associated with brain structures than the total number of network members.     

Large‐scale reconfiguration of connectivity patterns among attentional networks during context‐dependent adjustment of cognitive control

The ability to adjust our behavior flexibly depending on situational demands and changes in the environment is an important characteristic of cognitive control. Previous studies have proved that this type of adaptive control plays a crucial role in selective attention, but have barely explored whether and how attentional networks support adaptive control. In the present study, a Stroop task with a different proportion of incongruent trials was used to investigate the brain activity and connectivity of six typical attentional control networks (i.e., the fronto‐parietal network (FPN), cingulo‐opercular network (CON), default mode network (DMN), dorsal attention network (DAN), and ventral attention network/salience network (VAN/SN)) in the environment with changing control demand. The behavioral analysis indicated a decreased Stroop interference (incongruent vs. congruent trial response time [RT]) with the increase in the proportion of incongruent trials within a block, indicating that cognitive control was improved there. The fMRI data revealed that the attenuate Stroop interference was accompanied by the activation of frontal and parietal regions, such as bilateral dorsolateral prefrontal cortex and anterior cingulate cortex. Crucially, the improved cognitive control induced by the increased proportion of incongruent trials was associated with the enhanced functional connectivity within the five networks, and a greater connection between CON with the DAN/SN, and between DMN with the CON/DAN/SN. Meanwhile, however, the functional coupling between the FPN and VAN was decreased. These results suggest that flexible regulations of cognitive control are implemented by the large‐scale reconfiguration of connectivity patterns among the attentional networks.     

Negative information enhances the attentional blink in dysphoria

Background: Research has suggested that depression is characterized by maintained attention for negative information. Methods: In this study, we examined whether maintained attention for emotional words influenced the attentional blink in a sample of stable dysphoric (n=14) and non‐dysphoric (n=14) undergraduates. In a rapid serial visual presentation of white words, two green target words (T1, T2) had to be identified. If attention is maintained at negative information, T2 identification should be hampered by presenting a negative word at T1. Results: Results supported the hypothesis that negative words as T1 hampered the identification of T2 words if T2 was presented within 300 ms. Conclusions: These results improve our understanding of the nature of attentional bias in dysphoria. Depression and Anxiety, 2009. © 2008 Wiley‐Liss, Inc.     

Threat-related attentional biases: an analysis of three attention systems

It is unclear how threat-related attentional biases affect multiple attention systems. This study used a new modification of a reaction time paradigm to examine whether inter-trial task-irrelevant fearful faces influenced the efficiency of alerting, orienting, and executive attention, and whether effects varied with level of state anxiety. Participants, 63 non-disordered adults (17 males and 46 females), reported on their subjective state anxiety and completed a modified version of the Attention Network Test in which fearful or neutral faces or control stimuli were presented briefly (50 ms) between trials of the task, but provided no task-relevant information. Across all participants, state anxiety was positively correlated with alerting, whereas fearful versus neutral faces were linked to decreased alerting efficiency. Contrasting high and low anxiety groups showed that fearful versus neutral faces reduced executive attention in the low state anxiety group only, suggesting decreased distraction by irrelevant stimuli in the high state anxiety group. Results document threat-related attentional biases that varied with attention system but failed to find enhanced bias effects among those with higher state anxiety in a typical range. This modification of the Attention Network Test, which added presentation of emotional distracters, provides a potentially useful new method for assessing the impact of task-irrelevant emotional stimuli on three aspects of attention performance.     

Dissociation between top-down attentional control and the time course of visual attention as measured by attentional dwell time in patients with mild cognitive impairment

Studies of the time course of visual attention have identified a temporary functional blindness to the second of sequentially presented stimuli in that the attentional cost of attending to one visual stimulus may lead to impairments in identifying a second stimulus presented within 500 ms of the first. This phenomenon is known as the attentional blink or attentional dwell time. The neural correlates of the attentional blink and its relationship to mechanisms that control attention are unknown. To examine this relationship we tested healthy controls and subjects in the preclinical stage of Alzheimer's disease, known as mild cognitive impairment (MCI), on a paradigm which affords quantification of both the attentional blink and the top-down control of attention. When subjects were asked to identify both a number and a letter that were rapidly and sequentially presented on a visual display, the detrimental effect that identifying the first stimulus had on the ability to identify the second served as a measure of the attentional blink. When asked to identify only one of the two stimuli, the ability to ignore the first stimulus was a function of their top-down attentional control. The MCI subjects demonstrated a normal attentional dwell time but in contrast they showed impaired top-down attentional control within the same paradigm. This dissociation suggests that these two aspects of visual attention are subserved by different neural systems. The possible neural correlates of these two attentional functions are discussed.     

Neurocognitive profiles in older adults with and without major depression

OBJECTIVES: To delineate the differences between older persons with and without a diagnosis of major depression. METHODS: Participants were recruited from three outpatient clinics serving older patients at St Michael's Hospital. To be included in the study, participants had to speak English and have no evidence of significant sensory deficits that would interfere with neuropsychological testing. Participants were excluded if they had active delirium, active CNS disease (including dementia), active substance abuse, unstable medical disease, recent ECT treatment and a current/past diagnosis of a psychotic disorder. The diagnosis of major depression was made by qualified professionals in accordance with established guidelines. Participants were administered structured measures assessing global cognition, medical co-morbidity, subjective memory complaints, mood and detailed neurocognitive testing evaluating working memory, attention and speed of processing. Differences between depressed and non-depressed subjects with respect to these measures were analyzed using analysis of variance (ANOVA). RESULTS: Thirty-six participants were included in this study. The depressed (n = 17) and non-depressed (n = 19) groups were well matched in terms of age, education, medical co-morbidity and mini-mental state exam (MMSE) score. While the depressed subgroup had significantly higher subjective memory, language and cognitive complaints, there were no significant differences observed between the two subgroups on measures of memory and learning, attention and speed of information processing, fine motor dexterity and verbal fluency. CONCLUSION: This study suggests that while significant depressive symptoms are strongly associated with increased cognitive complaints, they are not associated necessarily with objective cognitive impairment.     

Investigation of an attentional bias for fear-related material in obsessive-compulsive checkers

Prior studies on attentional biases in obsessive-compulsive disorder (OCD) have yielded conflicting results. Using a new methodology based on a spatial cueing paradigm, it was investigated whether OCD checkers display heightened vigilance for concern-related material or difficulties disengaging from such stimuli. Twenty-eight OCD patients, 21 of whom were checkers, were compared to 27 controls. In the spatial cueing paradigm task, patients and controls responded to a visual target at one out of two possible locations, which was preceded by a verbal cue word presented at the same or at the opposite location of the target. Cue words were either checking-relevant (e.g., doubt), neutral (e.g., box), or paranoia-related (e.g., spy). No evidence for an attentional bias in OCD checkers was found. This study is in accordance with previous studies, which were unable to detect attentional biases in OCD patients.     

Right temporoparietal junction and attentional reorienting

The interaction between goal‐directed and stimulus‐driven attentional control allows humans to rapidly reorient to relevant objects outside the focus of attention—a phenomenon termed contingent reorienting. Neuroimaging studies have observed activation of the ventral and dorsal attentional networks, but specific involvement of each network remains unclear. The present study aimed to determine whether both networks are critical to the processes of top‐down contingent reorienting. To this end, we combined the contingent attentional capture paradigm with the use of transcranial magnetic stimulation (TMS) to interfere with temporoparietal junction (TPJ; ventral network) and frontal eye field (dorsal network) activity. The results showed that only right TPJ (rTPJ) TMS modulated contingent orienting. Furthermore, this modulation was highly dependent on visual fields: rTPJ TMS increased contingent capture in the left visual field and decreased the effect in the right visual field. These results demonstrate a critical involvement of the ventral network in attentional reorienting and reveal the spatial selectivity within such network. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.