The effects of cognitive loading on balance control in patients with multiple sclerosis

The aim of this study was to compare the effects of concurrent cognitive task (silent backward counting) on balance performance between two groups of multiple sclerosis (MS) (n = 23) and healthy (n = 23) participates. Three levels of postural difficulty were studied on a force platform, i.e. rigid surface with eyes open, rigid surface with eyes closed, and foam surface with eyes closed. A mixed model analysis of variance showed that under difficult sensory condition of foam surface with eyes closed, execution of concurrent cognitive task caused a significant decrement in variability of sway velocity in anteroposterior direction for the patient group (P < 0.01) while this was not the case for healthy participants (P = 0.22). Also, the variability of sway velocity in mediolateral direction was significantly decreased during concurrent execution of cognitive task in patient group (P < 0.01) and not in healthy participants (P = 0.39). Furthermore, in contrast to single tasking, dual tasking had the ability to discriminate between the 2 groups in all conditions of postural difficulty. In conclusion, findings of variability in sway velocity seem to confirm the different response to cognitive loading between two groups of MS and healthy participants.     

Petroleum ether extract of Cnidium monnieri ameliorated scopolamine-induced amnesia through adrenal gland-mediated mechanism in male rats

AIM: Our previous study indicated petroleum ether layer of Cnidium monnieri L. Cuss. (CM) and its ingredient osthole could alleviate scopolamine-induced amnesia in female rats. MATERIALS AND METHODS: Hence, this study was desired to investigate the mechanism of the ameliorating effects of petroleum ether layer of CM on the performance impairment of inhibitory avoidance task and Morris water maze induced by scopolamine in male rats. RESULTS: CM at 0.1-0.6g/kg orally administered 60 min before the training trial ameliorated the scopolamine-induced performance impairment on inhibitory avoidance learning and water maze in male rats. Only adrenalectomy but not peripheral cholinergic antagonist scopolamine methylbromide and catecholaminergic neurotoxin 6-hydroxydopamine blocked the ameliorating effects of CM on scopolamine-induced performance impairment in rats. CONCLUSION: Therefore, we demonstrated that the ameliorating effects of CM on scopolamine-induced performance impairment may be related to activating the adrenal gland and central acetylcholingeric neuron, instead of peripheral nervous system.     

云计算中基于进化算法的任务调度策略

任务调度是云计算的关键问题之一,它的调度策略与算法直接影响到云计算系统的性能与成本。通过研究基于粒子群算法和遗传算法的任务调度策略,提出了一种基于进化策略的PSO-CM算法。该算法通过在粒子群算法中引入遗传算法的交叉变异策略来提高粒子群算法的全局收敛效果,并且证明了PSO-CM算法是一种全局收敛算法。Matlab仿真实验表明,该算法能够达到全局收敛,且收敛速度和稳定性优于传统的调度算法。     

基于fMRI任务态与静息态对头针疗法的研究进展

头针疗法是针灸体系的重要组成部分且广泛应用于临床,但是有关其作用原理研究的文献却不足以完全阐明头针机理,并指导其发展方向.功能磁共振成像技术因其独特优势,成为穴位针刺脑部中枢效应机制研究的首选方法.通过阅读分析相关文献及该领域整体研究趋势,发现应用功能磁共振成像技术对头针疗法进行研究主要集中在特异性脑区激活、针刺作用机...     

行为训练诱导的大鼠背海马结构内c—Fos表达的老年相关性变化

采用避暗回避反应实验和免疫细胞化学相结合的方法,选用5个实验组（即：空白对照组、实验对照组、假训练组、训练组和记忆唤醒组）,对不同月龄大鼠背海马结构中的c-Fos表达进行了观察。结果发现：老年大鼠在避暗回避训练中,探索次数多于青年和成年大鼠,且滞留时间明显缩短;成年和老年大鼠在训练、假训练和记忆唤醒后,背海马内c-Fos的表达明显低于青年组大鼠,以训练组最为显著。该结果一方面表明随年龄的增长,海马神经元对应激和学习记忆尤其是后者的反应性降低;另一方面也提示成年和老年组大鼠背海马区神经元可能有丢失现象。     

Progressive brain dysfunction following intracerebroventricular infusion of beta(1-42)-amyloid peptide

The behavioral, neurochemical and histological changes of rats subjected to 3 days treatment with intracerebroventricular infusion of beta-amyloid peptides(Abeta)(1-42) were investigated 20 days and 80 days after the surgery. Abeta(1-42) produced a dose-dependent and a time-dependent impairment in the spontaneous alternation performance in the Y-maze (spatial working memory), place navigation task in a water maze (spatial reference memory) and passive avoidance retention (non-spatial long-term memory) at doses of 10 and 20 microg/rat. The learning impairments were more severe at 80 days than 20 days after infusion of Abeta(1-42). At 25 days after the infusion, a significant decrease in hemicholinium-3 (HC-3) binding was observed only in the hippocampus, although choline acetyltransferase (ChAT) activity was unchanged in the brain regions tested as compared with the vehicle (Abeta(40-1)) treatment. In contrast, the reduction in ChAT activity 85 days after Abeta(1-42) infusion was significant in hippocampus and striatum. HC-3 binding was also significantly decreased in the posterior cortex, hippocampus and striatum. In the histological analysis, brain atrophy was observed inasmuch as ventricular enlargement and neuronal damage in the CA1 area of the hippocampus were seen 85 days after Abeta(1-42) infusion. These results suggest that the rats subjected to intracerebroventricular infusion of Abeta(1-42) suffered from progressive brain dysfunction, and could be useful as an animal model for evaluating the developmental processes at the early and/or middle stage of Alzheimer's-type dementia.     

双重任务脑力负荷的心理生理学评定

目的探讨心理生理学方法在双重任务脑力负荷评定中的意义。方法采用事件相关电位Ｐ３波潜时（ＬＡＴ）和波幅（ＡＭＰ）、逐次心跳间期（ＩＢＩ）及心率变异性（ＨＲＶ）、逐次呼吸间期（ＩＲＩ）及呼吸变异性（ＲＲＶ）、眨眼率（ＢＲ）等心理生理学指标，评定了１６名男性青年受试者完成三种不同难度双重任务时的脑力负荷。双重任务由视觉追踪主任务和Ｓｔｅｒｎｂｅｒｇ副任务组成，其难度由主任务目标运动的速度和维度控制。结果①随任务难度增加，Ｐ３波ＬＡＴ延长（Ｐ＜０．０１），ＡＭＰ无显著性变化（Ｐ＞０．０５）；②ＩＢＩ及ＨＲＶ在中等难度任务时最小，其中ＩＢＩ在任务间有显著性差异（Ｐ＜０．０１）；③ＩＲＩ随任务难度增加而减小（Ｐ＜０．０５），ＲＲＶ任务间无显著性差异（Ｐ＞０．０５）；④ＢＲ在三种任务条件与对照条件时相比显著降低（Ｐ＜０．０１）。结论各指标与脑力负荷均有一定关系，但单一指标评定脑力负荷有局限性，多种心理生理学指标综合评定是双重任务条件下脑力负荷评定更为适宜的方法。     

Test‐retest reliability of the default mode network in a multi‐centric fMRI study of healthy elderly: Effects of data‐driven physiological noise correction techniques

Understanding how to reduce the influence of physiological noise in resting state fMRI data is important for the interpretation of functional brain connectivity. Limited data is currently available to assess the performance of physiological noise correction techniques, in particular when evaluating longitudinal changes in the default mode network (DMN) of healthy elderly participants. In this 3T harmonized multisite fMRI study, we investigated how different retrospective physiological noise correction (rPNC) methods influence the within‐site test‐retest reliability and the across‐site reproducibility consistency of DMN‐derived measurements across 13 MRI sites. Elderly participants were scanned twice at least a week apart (five participants per site). The rPNC methods were: none (NPC), Tissue‐based regression, PESTICA and FSL‐FIX. The DMN at the single subject level was robustly identified using ICA methods in all rPNC conditions. The methods significantly affected the mean z‐scores and, albeit less markedly, the cluster‐size in the DMN; in particular, FSL‐FIX tended to increase the DMN z‐scores compared to others. Within‐site test‐retest reliability was consistent across sites, with no differences across rPNC methods. The absolute percent errors were in the range of 5–11% for DMN z‐scores and cluster‐size reliability. DMN pattern overlap was in the range 60–65%. In particular, no rPNC method showed a significant reliability improvement relative to NPC. However, FSL‐FIX and Tissue‐based physiological correction methods showed both similar and significant improvements of reproducibility consistency across the consortium (ICC = 0.67) for the DMN z‐scores relative to NPC. Overall these findings support the use of rPNC methods like tissue‐based or FSL‐FIX to characterize multisite longitudinal changes of intrinsic functional connectivity. Hum Brain Mapp 37:2114–2132, 2016. © 2016 Wiley Periodicals, Inc.     

The relationship between behavior acquisition and persistence abilities: Involvement of adult hippocampal neurogenesis

The influence of the learning process on the persistence of the newly acquired behavior is relevant both for our knowledge of the learning/memory mechanisms and for the educational policy. However, it is unclear whether during an operant conditioning process with a continuous reinforcement paradigm, individual differences in acquisition are also associated to differences in persistence of the acquired behavior. In parallel, adult neurogenesis has been implicated in spatial learning and memory, but the specific role of the immature neurons born in the adult brain is not well known for this process. We have addressed both questions by analyzing the relationship between water maze task acquisition scores, the persistence of the acquired behavior, and the size of the different subpopulations of immature neurons in the adult murine hippocampus. We have found that task acquisition and persistence rates were negatively correlated: the faster the animals find the water maze platform at the end of acquisition stage, the less they persist in searching for it at the learned position in a subsequent non‐reinforced trial; accordingly, the correlation in the number of some new neurons' subpopulations and the acquisition rate is negative while with persistence in acquired behavior is positive. These findings reveal an unexpected relationship between the efficiency to learn a task and the persistence of the new behavior after a non‐reinforcement paradigm, and suggest that the immature neurons might be involved in different roles in acquisition and persistence/extinction of a learning task. © 2016 Wiley Periodicals, Inc.     

Human perceptual decision making: Disentangling task onset and stimulus onset

The left dorsolateral prefrontal cortex (ldlPFC) has been highlighted as a key actor in human perceptual decision‐making (PDM): It is theorized to support decision‐formation independently of stimulus type or motor response. PDM studies however generally confound stimulus onset and task onset: when the to‐be‐recognized stimulus is presented, subjects know that a stimulus is shown and can set up processing resources—even when they do not know which stimulus is shown. We hypothesized that the ldlPFC might be involved in task preparation rather than decision‐formation. To test this, we asked participants to report whether sequences of noisy images contained a face or a house within an experimental design that decorrelates stimulus and task onset. Decision‐related processes should yield a sustained response during the task, whereas preparation‐related areas should yield transient responses at its beginning. The results show that the brain activation pattern at task onset is strikingly similar to that observed in previous PDM studies. In particular, they contradict the idea that ldlPFC forms an abstract decision and suggest instead that its activation reflects preparation for the upcoming task. We further investigated the role of the fusiform face areas and parahippocampal place areas which are thought to be face and house detectors, respectively, that feed their signals to higher level decision areas. The response patterns within these areas suggest that this interpretation is unlikely and that the decisions about the presence of a face or a house in a noisy image might instead already be computed within these areas without requiring higher‐order areas. Hum Brain Mapp 35:3170–3187, 2014. © 2013 Wiley Periodicals, Inc.