Functional cortical connectivity analysis of mental fatigue unmasks hemispheric asymmetry and changes in small-world networks

Changes in functional connectivity across mental states can provide richer information about human cognition than simpler univariate approaches. Here, we applied a graph theoretical approach to analyze such changes in the lower alpha (8–10 Hz) band of EEG data from 26 subjects undergoing a mentally-demanding test of sustained attention: the Psychomotor Vigilance Test. Behavior and connectivity maps were compared between the first and last 5 min of the task. Reaction times were significantly slower in the final minutes of the task, showing a clear time-on-task effect. A significant increase was observed in weighted characteristic path length, a measure of the efficiency of information transfer within the cortical network. This increase was correlated with reaction time change. Functional connectivity patterns were also estimated on the cortical surface via source localization of cortical activities in 26 predefined regions of interest. Increased characteristic path length was revealed, providing further support for the presence of a reshaped global topology in cortical connectivity networks under fatigue state. Additional analysis showed an asymmetrical pattern of connectivity (right > left) in fronto-parietal regions associated with sustained attention, supporting the right-lateralization of this function. Interestingly, in the fatigue state, significance decreases were observed in left, but not right fronto-parietal connectivity. Our results indicate that functional network organization can change over relatively short time scales with mental fatigue, and that decreased connectivity has a meaningful relationship with individual difference in behavior and performance.     

The effect of methylphenidate on very low frequency electroencephalography oscillations in adult ADHD

Altered very low-frequency electroencephalographic (VLF-EEG) activity is an endophenotype of ADHD in children and adolescents. We investigated VLF-EEG case-control differences in adult samples and the effects of methylphenidate (MPH). A longitudinal case-control study was conducted examining the effects of MPH on VLF-EEG (.02–0.2 Hz) during a cued continuous performance task. 41 untreated adults with ADHD and 47 controls were assessed, and 21 cases followed up after MPH treatment, with a similar follow-up for 38 controls (mean follow-up = 9.4 months). Cases had enhanced frontal and parietal VLF-EEG and increased omission errors. In the whole sample, increased parietal VLF-EEG correlated with increased omission errors. After controlling for subthreshold comorbid symptoms, VLF-EEG case-control differences and treatment effects remained. Post-treatment, a time by group interaction emerged; VLF-EEG and omission errors reduced to the same level as controls, with decreased inattentive symptoms in cases. Reduced VLF-EEG following MPH treatment provides preliminary evidence that changes in VLF-EEG may relate to MPH treatment effects on ADHD symptoms; and that VLF-EEG may be an intermediate phenotype of ADHD. Further studies of the treatment effect of MPH in larger controlled studies are required to formally evaluate any causal link between MPH, VLF-EEG and ADHD symptoms.     

Strategic retrieval processing and the impact of knowing when a memory was first created

Retrieval orientation refers to a process where participants strategically alter how a memory cue is processed in response to different task demands. In the present study we explored whether retrieval orientation is influenced by knowing when an old stimulus was first encoded. Participants completed separate remember/know test blocks for old items from a recent delay (40 min) and old items from a remote delay (48 h). Manipulations at encoding ensured that performance levels were matched between these two blocks, thus avoiding confounds with differences in retrieval effort. Importantly, a third test block comprised old items from both delays randomly intermixed. As the nature of the old items varies unpredictably in the mixed block, it should not be possibly to adopt a specific retrieval orientation and the mixed block therefore acts as a control condition. Participants saw the words “mixed,” “recent” or “remote” prior to each test block. Comparing ERPs from the recent and remote blocks permitted an investigation of whether participants alter their retrieval orientation in response to the specific length of the retention interval. Comparing ERPs from the pure (recent and remote) test blocks to ERPs from the mixed block permitted an investigation of whether delay information per se led to differences in retrieval strategy. Analysis of the ERP data found no differences between the recent and remote blocks. However, ERPs from these pure blocks were significantly less positive than ERPs from the mixed block from 200 ms towards the end of the epoch. The findings suggest that the delay information was useful in a general sense and encouraged retrieval strategies distinct from those engaged in the mixed block. We speculate that such strategies might relate to whether or not the retrieval search is specific and constrained and/or whether processes that serve to reinstate the original encoding context are engaged.     

The Ahmadiyya and the Study of Comparative Religion in Indonesia: Controversies and Influences

As an organization of foreign origin, the existence and contribution of the Ahmadiyya in Indonesia has been a subject of debate. Some scholars ignore it completely as unimportant, while others consider that it has had significant influence. The contribution of the Ahmadiyya to Indonesian Islam most asserted by the movement itself is its efforts to check and respond to Christian missionary activity. In what way has the movement actually made a contribution to that effort? How widespread is the influence of the Ahmadiyya in the discourse on Christianity, in particular, and the study of comparative religion, in general, in Indonesia? Why has the Ahmadiyya paid more attention to the issue of Christianity than other Muslim groups? This article aims to answer these questions by analysing literature on Christianity written and distributed by the Ahmadiyya in Indonesia and the effect this has had on relations between Islam and Christianity in two fields – religious mission and academia. The article presents three propositions. First, Ahmadiyya literature, with its apologetic, polemical and controversial character, had a significant influence on the academic study of comparative religion during two periods of instability: the late colonial era and the first two decades after the declaration of independence in 1945. Second, Ahmadiyya literature on Christianity has been most influential through the way it sets out to create a sense of the superiority of Islam and its compatibility with modernity. Third, for the Ahmadiyya, the issue of Christianity, particularly the death of Jesus, has been used as evidence that Mirza Ghulam Ahmad is the second Messiah.     

冠心病患者的抑郁和焦虑

许多临床研究表明,冠心病患者常发生抑郁及焦虑。而在严重精神症状（如抑郁或/和焦虑）者中有较高的冠心病发生率。抑郁增加冠心病患者的不良心血管事件发生率,影响预后。其机制有如下几个方面：对医疗措施及生活方式改变的依从性差、血小板功能异常、血管内皮功能紊乱以及心率变异性降低。选择性5-羟色胺再摄取抑制剂由于其较好的耐受性且无明显的心血管副作用而应用于冠心病合并抑郁及焦虑的药物治疗并改善患者的生活质量。但仍需要更大规模的临床研究以确定抑郁及焦虑对冠心病预后的影响。临床上应更加关注焦虑对冠心病的影响,进一步探讨焦虑能否作为冠心病的危险因素。     

变异性心绞痛患者心率变异性与冠状动脉病变关系的研究

研究变异性心绞痛患者 ST 段抬高对心率变异性的影响。回顾性分析122例变异性心绞痛患者 ST 段抬高幅度及持续时间对心率变异性的影响;心率变异性与冠状动脉病变及病变支数、狭窄程度有相关性。结果心率变异性在 ST 段抬高≥0．4mv 患者中较 ST 段抬高＜0．4mv 患者中明显降低（P＜0．05）;其在 ST 段抬高持续时间≥3min 患者中较 ST 段抬高持续时间＜3min 患者中明显降低（P＜0．05）;其在冠状动脉狭窄≥50％患者中较冠状动脉狭窄＜50％患者中明显降低（P＜0．05）;心率变异性在多支较单支病变明显降低（P ＜0．05）,单支病变狭窄程度≥75％较50％～75％者明显降低（P＜0．05）。提示变异性心绞痛患者自主神经系统受损程度与冠状动脉缺血严重程度,缺血持续时间密切相关,心率变异性能一定程度反映变异性心绞痛患者冠状动脉病变严重程度。     

肺微小浸润腺癌及浸润前病变HRCT影像特征

为总结肺微小浸润腺癌(MIA)、原位腺癌(AIS)及不典型腺瘤样增生(AAH)结节的HRCT影像特征,回顾性收集43例术前2周内行HRCT检查、经胸腔镜切除、组织病理学证实的50个肺结节,分析结节大小、成分及内部特征.结果显示所有AAH表现为纯磨玻璃结节(pGGN),且≤1.0cm,空气支气管征未见,空泡征少见;86％AIS表现为pGGN,71％的AIS≤1.0cm,且空泡征常见(相对于AAH);95％的MIA表现为混合磨玻璃结节(mGGN),其余为实性结节,90％的MIA＞1.0cm,空气支气管征常见(相对于AIS).因此结节的大小、成分、空泡征及空气支气管征在一定程度上有助于MIA、AIS及AAH的鉴别.