Individual Differences in Impulsivity Predict Head Motion during Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) provides valuable data for understanding the human mind and brain disorders, but in-scanner head motion introduces systematic and spurious biases. For example, differences in MRI measures (e.g., network strength, white matter integrity) between patient and control groups may be due to the differences in their head motion. To determine whether head motion is an important variable in itself, or just simply a confounding variable, we explored individual differences in psychological traits that may predispose some people to move more than others during an MRI scan. In the first two studies, we demonstrated in both children (N  =  245) and adults (N  =  581) that head motion, estimated from resting-state functional MRI and diffusion tensor imaging, was reliably correlated with impulsivity scores. Further, the difference in head motion between children with attention deficit hyperactivity disorder (ADHD) and typically developing children was largely due to differences in impulsivity. Finally, in the third study, we confirmed the observation that the regression approach, which aims to deal with motion issues by regressing out motion in the group analysis, would underestimate the effect of interest. Taken together, the present findings provide empirical evidence that links in-scanner head motion to psychological traits.     

Biological Traits Successfully Predict the Effects of Restoration Management on Macroinvertebrates in Shallow Softwater Lakes

Many shallow softwater lakes are being affected by eutrophication and acidification. In these small lakes decaying organic material usually accumulates and characteristic plant and animal species disappear. In many degraded lakes organic matter and macrophytes are being removed in order to restore the lakes to their original state. To assess the effects of restoration management in softwater lakes on aquatic macroinvertebrates, changes in the species assemblages were studied in four degraded lakes in the Netherlands undergoing restoration measures. The degraded lakes still harboured species characteristic of pristine softwaters. However, most of these species were not recorded after restoration measures were taken. Species’ densities declined dramatically during the execution of restoration measures. Swimming and abundant species were more likely to survive the restoration measures than other species. The first years after restoration, the lakes did not meet the habitat requirements for a number of species. Species requiring vegetation for ovipositioning, animal food sources and swards of vegetation as habitat declined. Because recolonization is expected to be restricted, it is recommended to ensure the survival of relict populations when taking measures to restore degraded softwater lakes. This may be achieved by phasing restoration measures in space and time, hereby minimizing mortality during the execution of restoration measures and by preserving habitat conditions required by characteristic species.     

Perception of Social Interactions for Spatially Scrambled Biological Motion

It is vitally important for humans to detect living creatures in the environment and to analyze their behavior to facilitate action understanding and high-level social inference. The current study employed naturalistic point-light animations to examine the ability of human observers to spontaneously identify and discriminate socially interactive behaviors between two human agents. Specifically, we investigated the importance of global body form, intrinsic joint movements, extrinsic whole-body movements, and critically, the congruency between intrinsic and extrinsic motions. Motion congruency is hypothesized to be particularly important because of the constraint it imposes on naturalistic action due to the inherent causal relationship between limb movements and whole body motion. Using a free response paradigm in Experiment 1, we discovered that many naïve observers (55%) spontaneously attributed animate and/or social traits to spatially-scrambled displays of interpersonal interaction. Total stimulus motion energy was strongly correlated with the likelihood that an observer would attribute animate/social traits, as opposed to physical/mechanical traits, to the scrambled dot stimuli. In Experiment 2, we found that participants could identify interactions between spatially-scrambled displays of human dance as long as congruency was maintained between intrinsic/extrinsic movements. Violating the motion congruency constraint resulted in chance discrimination performance for the spatially-scrambled displays. Finally, Experiment 3 showed that scrambled point-light dancing animations violating this constraint were also rated as significantly less interactive than animations with congruent intrinsic/extrinsic motion. These results demonstrate the importance of intrinsic/extrinsic motion congruency for biological motion analysis, and support a theoretical framework in which early visual filters help to detect animate agents in the environment based on several fundamental constraints. Only after satisfying these basic constraints could stimuli be evaluated for high-level social content. In this way, we posit that perceptual animacy may serve as a gateway to higher-level processes that support action understanding and social inference.     

生物运动识别的信息加工机制

识别其他生物体的运动对于个体的生存和社会交互都有极为重要的意义.本文首先基于生物运动识别的行为学、心理物理学、脑损伤和精神障碍研究介绍了生物运动识别的一些特性和影响因素;然后基于神经影像学、脑损伤和神经电生理学研究从视觉系统背腹侧双通路加工的角度,梳理了其信息加工机制的进展;最后对生物运动识别信息加工神经机制的研究方向提出了一点建议,并指出研究过程中需要注意的问题.     

Infarction Distribution Pattern in Acute Stroke May Predict the Extent of Leptomeningeal Collaterals

Objective

The aim of this study was to evaluate whether the distribution pattern of early ischemic changes in the initial MRI allows a practical method for estimating leptomeningeal collateralization in acute ischemic stroke (AIS).

Methods

Seventy-four patients with AIS underwent MRI followed by conventional angiogram and mechanical thrombectomy. Diffusion restriction in Diffusion weighted imaging (DWI) and correlated T2-hyperintensity of the infarct were retrospectively analyzed and subdivided in accordance with Alberta Stroke Program Early CT score (ASPECTS). Patients were angiographically graded in collateralization groups according to the method of Higashida, and dichotomized in 2 groups: 29 subjects with collateralization grade 3 or 4 (well-collateralized group) and 45 subjects with grade 1 or 2 (poorly-collateralized group). Individual ASPECTS areas were compared among the groups.

Results

Means for overall DWI-ASPECTS were 6.34 vs. 4.51 (well vs. poorly collateralized groups respectively), and for T2-ASPECTS 9.34 vs 8.96. A significant difference between groups was found for DWI-ASPECTS (p<0.001), but not for T2-ASPECTS (p = 0.088). Regarding the individual areas, only insula, M1-M4 and M6 showed significantly fewer infarctions in the well-collateralized group (p-values <0.001 to 0.015). 89% of patients in the well-collateralized group showed 0–2 infarctions in these six areas (44.8% with 0 infarctions), while 59.9% patients of the poor-collateralized group showed 3–6 infarctions.

Conclusion

Patients with poor leptomeningeal collateralization show more infarcts on the initial MRI, particularly in the ASPECTS areas M1 to M4, M6 and insula. Therefore DWI abnormalities in these areas may be a surrogate marker for poor leptomeningeal collaterals and may be useful for estimation of the collateral status in routine clinical evaluation.     

尼氟酸对晚期内皮祖细胞生物学特性的影响

目的:探讨ClCa通道抑制剂--尼氟酸(Niflumic,NFA)对大鼠骨髓来源的晚期内皮祖细胞(endothelial progenitor cells,EPCs)生物学特性的影响。方法:密度梯度离心法分离大鼠骨髓单核细胞,应用EGM-2完全培养液进行体外培养,以第三代或第四代的晚期EPCs作为靶细胞,应用RT-PCR检测晚期EPCs上是否存在Cl Ca通道标志基因TMEM16A和Cl Ca4的表达。采用CCK-8法、Ed U标记法、划痕实验、Boyden小室实验及Matrigel法分别检测10μmol/L NFA对细胞增殖、迁移及体外血管形成能力的影响;应用荧光定量PCR及流式细胞术检测内皮分化标志v WF和CD31基因及蛋白的表达。结果:晚期EPCs表达ClCa通道标志基因TMEM16A和ClCa4;NFA抑制晚期EPCs的迁移功能(P0.05);但对EPCs的增殖、分化及成血管能力有促进作用。NFA上调了晚期EPCs的CD31和v WF基因和蛋白表达。结论:NFA能促进EPCs的增殖、分化及成血管能力,抑制EPCs的迁移能力。NFA对EPCs生物学特性的这类影响将为心血管疾病治疗药物选择方面提供一定的参考依据。     

Speed of Human Biological Form and Motion Processing

Recent work suggests that biological motion processing can begin within ~110 ms of stimulus onset, as indexed by the P1 component of the event-related potential (ERP). Here, we investigated whether modulation of the P1 component reflects configural processing alone, rather than the processing of both configuration and motion cues. A three-stimulus oddball task was employed to evaluate bottom-up processing of biological motion. Intact point-light walkers (PLWs) or scrambled PLWs served as distractor stimuli, whereas point-light displays of tool motion served as standard and target stimuli. In a second experiment, the same design was used, but the dynamic stimuli were replaced with static point-light displays. The first experiment revealed that dynamic PLWs elicited a larger P1 as compared to scrambled PLWs. A similar P1 increase was also observed for static PLWs in the second experiment, indicating that these stimuli were more salient than static, scrambled PLWs. These findings suggest that the visual system can rapidly extract global form information from static PLWs and that the observed P1 effect for dynamic PLWs is not dependent on the presence of motion cues. Finally, we found that the N1 component was sensitive to dynamic, but not static, PLWs, suggesting that this component reflects the processing of both form and motion information. The sensitivity of P1 to static PLWs has implications for dynamic form models of biological motion processing that posit temporal integration of configural cues present in individual frames of PLW animations.     

Impairments of Biological Motion Perception in Congenital Prosopagnosia

Prosopagnosia is a deficit in recognizing people from their faces. Acquired prosopagnosia results after brain damage, developmental or congenital prosopagnosia (CP) is not caused by brain lesion, but has presumably been present from early childhood onwards. Since other sensory, perceptual, and cognitive abilities are largely spared, CP is considered to be a stimulus-specific deficit, limited to face processing. Given that recent behavioral and imaging studies indicate a close relationship of face and biological-motion perception in healthy adults, we hypothesized that biological motion processing should be impaired in CP. Five individuals with CP and ten matched healthy controls were tested with diverse biological-motion stimuli and tasks. Four of the CP individuals showed severe deficits in biological-motion processing, while one performed within the lower range of the controls. A discriminant analysis classified all participants correctly with a very high probability for each participant. These findings demonstrate that in CP, impaired perception of faces can be accompanied by impaired biological-motion perception. We discuss implications for dedicated and shared mechanisms involved in the perception of faces and biological motion.     

逃逸速率对分子马达定向运动的影响

在考虑逃逸速率的情况下采用主方程方法研究分子马达,计算了逃逸速率对分子马达的漂移速率、扩散系数、停留时间以及分子马达在轨道上移动的距离．通过计算发现,逃逸速率影响分子马达的定向运动．     

The Use of Magnetic Resonance Spectroscopy as a Tool for the Measurement of Bi-hemispheric Transcranial Electric Stimulation Effects on Primary Motor Cortex Metabolism

Transcranial direct current stimulation (tDCS) is a neuromodulation technique that has been increasingly used over the past decade in the treatment of neurological and psychiatric disorders such as stroke and depression. Yet, the mechanisms underlying its ability to modulate brain excitability to improve clinical symptoms remains poorly understood ³³. To help improve this understanding, proton magnetic resonance spectroscopy (¹H-MRS) can be used as it allows the in vivo quantification of brain metabolites such as γ-aminobutyric acid (GABA) and glutamate in a region-specific manner ⁴¹. In fact, a recent study demonstrated that ¹H-MRS is indeed a powerful means to better understand the effects of tDCS on neurotransmitter concentration ³⁴. This article aims to describe the complete protocol for combining tDCS (NeuroConn MR compatible stimulator) with ¹H-MRS at 3 T using a MEGA-PRESS sequence. We will describe the impact of a protocol that has shown great promise for the treatment of motor dysfunctions after stroke, which consists of bilateral stimulation of primary motor cortices ^27,30,31. Methodological factors to consider and possible modifications to the protocol are also discussed.     

Biological Motion Primes the Animate/Inanimate Distinction in Infancy

Given that biological motion is both detected and preferred early in life, we tested the hypothesis that biological motion might be instrumental to infants’ differentiation of animate and inanimate categories. Infants were primed with either point-light displays of realistic biological motion, random motion, or schematic biological motion of an unfamiliar shape. After being habituated to these displays, 12-month-old infants categorized animals and vehicles as well as furniture and vehicles with the sequential touching task. The findings indicated that infants primed with point-light displays of realistic biological motion showed better categorization of animates than those exposed to random or schematic biological motion. These results suggest that human biological motion might be one of the motion cues that provide the building blocks for infants’ concept of animacy.     

尖膀胱螺的生物学特征及光照对其生长繁殖影响的初步研究

尖膀胱螺Physa acuta是世界广泛分布的淡水螺类,在我国属外来入侵种.本文着重对该螺的形态特征、繁殖、发育及光照对螺生长和繁殖发育的影响等进行了实验观察和研究.尖膀胱螺个体中等,左旋,壳口无厣.喜聚居于水生植物较多、营养丰富的淡水区域.尖膀胱螺为雌雄同体,异体受精,有时也可自体受精.性成熟个体在条件适宜的情况下(温度、食物和光照)每天都可产卵,卵孵化率近100％.尖膀胱螺胚胎发育共经历卵裂期、囊胚期、原肠期、担轮幼虫期、面盆幼虫期、仔螺形成及出膜期7个时期.一般情况下,螺卵7～10 d可孵化,60 d即可性成熟.25℃、24 h连续光照条件下,尖膀胱螺体重明显增加,40 d就可以性成熟并产卵.     

Localization of Motor Neurons and Central Pattern Generators for Motor Patterns Underlying Feeding Behavior in Drosophila Larvae

Motor systems can be functionally organized into effector organs (muscles and glands), the motor neurons, central pattern generators (CPG) and higher control centers of the brain. Using genetic and electrophysiological methods, we have begun to deconstruct the motor system driving Drosophila larval feeding behavior into its component parts. In this paper, we identify distinct clusters of motor neurons that execute head tilting, mouth hook movements, and pharyngeal pumping during larval feeding. This basic anatomical scaffold enabled the use of calcium-imaging to monitor the neural activity of motor neurons within the central nervous system (CNS) that drive food intake. Simultaneous nerve- and muscle-recordings demonstrate that the motor neurons innervate the cibarial dilator musculature (CDM) ipsi- and contra-laterally. By classical lesion experiments we localize a set of CPGs generating the neuronal pattern underlying feeding movements to the subesophageal zone (SEZ). Lesioning of higher brain centers decelerated all feeding-related motor patterns, whereas lesioning of ventral nerve cord (VNC) only affected the motor rhythm underlying pharyngeal pumping. These findings provide a basis for progressing upstream of the motor neurons to identify higher regulatory components of the feeding motor system.     

土壤微生物生态学研究中的非培养方法

土壤微生物种类和数量是评价土壤健康质量的重要指标之一。然而环境中90%以上的微生物不能够通过传统的培养基培养方法获得。最近发展起来的分析方法如磷脂脂肪酸(PLFA)、BIOLOG微孔板和分子生物学的方法可从不同方面对土壤微生物群落进行更为详尽的分析。论文就土壤微生物生态学研究中使用的主要方法进行了综述。     

航天搭载对武夷名丛相关生理及生长特性的影响

以神舟八号飞船搭载的6种武夷名丛种子SP₁代株系为材料, 探讨航天搭载对武夷名丛SP₁代株系叶片形态、光合色素含量、叶绿素荧光参数、可溶性糖和蛋白质含量以及茶叶品质成分含量的影响, 分析航天搭载后武夷名丛生长和生理特性的变化, 从中筛选优良突变株。结果表明, 航天搭载后6个武夷名丛SP₁代植株的叶长、叶宽、节间长度和叶面积均发生变化, 其中, 雀舌、肉桂和奇丹的叶面积显著增加; 航天搭载显著提高雀舌、奇丹、肉桂和金毛猴的叶绿素及类胡萝卜素含量, 瞬时叶绿素荧光(F_t)和光量子效率(Qy)也有所增加, 这有利于提高光合效率; 武夷名丛航天搭载后表现出可溶性糖含量增加而蛋白质含量减少, 氨基酸和茶多酚含量下降, 儿茶素和咖啡碱含量上升。综合各项指标, 航天搭载后6个武夷名丛中雀舌可以作为有益变异株系加以选育。     

Brain Areas Active during Visual Perception of Biological Motion

Theories of vision posit that form and motion are represented by neural mechanisms segregated into functionally and anatomically distinct pathways. Using point-light animations of biological motion, we examine the extent to which form and motion pathways are mutually involved in perceiving figures depicted by the spatio-temporal integration of local motion components. Previous work discloses that viewing biological motion selectively activates a region on the posterior superior temporal sulcus (STSp). Here we report that the occipital and fusiform face areas (OFA and FFA) also contain neural signals capable of differentiating biological from nonbiological motion. EBA and LOC, although involved in perception of human form, do not contain neural signals selective for biological motion. Our results suggest that a network of distributed neural areas in the form and motion pathways underlie the perception of biological motion.     

Detection of Molecular Motion in Lyophilized Myelin by Nuclear Magnetic Resonance

Proton resonance spectroscopy was used to determine the state of the hydrocarbon regions in lyophilized and resuspended samples of nerve myelin. Measurements of the resonance line width indicate considerable freedom of motion within the hydrocarbon moiety of the myelin samples. Sharp thermal transitions of the line width were observed, suggesting that lyophilized myelin is in a liquid crystalline state.     

Measurement and Correction of Microscopic Head Motion during Magnetic Resonance Imaging of the Brain

Magnetic resonance imaging (MRI) is a widely used method for non-invasive study of the structure and function of the human brain. Increasing magnetic field strengths enable higher resolution imaging; however, long scan times and high motion sensitivity mean that image quality is often limited by the involuntary motion of the subject. Prospective motion correction is a technique that addresses this problem by tracking head motion and continuously updating the imaging pulse sequence, locking the imaging volume position and orientation relative to the moving brain. The accuracy and precision of current MR-compatible tracking systems and navigator methods allows the quantification and correction of large-scale motion, but not the correction of very small involuntary movements in six degrees of freedom. In this work, we present an MR-compatible tracking system comprising a single camera and a single 15 mm marker that provides tracking precision in the order of 10 m and 0.01 degrees. We show preliminary results, which indicate that when used for prospective motion correction, the system enables improvement in image quality at both 3 T and 7 T, even in experienced and cooperative subjects trained to remain motionless during imaging. We also report direct observation and quantification of the mechanical ballistocardiogram (BCG) during simultaneous MR imaging. This is particularly apparent in the head-feet direction, with a peak-to-peak displacement of 140 m.     

野生马齿苋生物学特性调查

试验主要以苏州本地的野生马齿苋植株为观察对象,调查生长发育习性,植株的形态特征,为今后推广马齿苋生产奠定基础。     

Phospholipid Motional Characteristics in a Dry Biological System : A P-Nuclear Magnetic Resonance Study of Hydrating Typha latifolia Pollen

Analysis of the proton-decoupled ³¹P-nuclear magnetic resonance (NMR) spectrum of fully hydrated Typha latifolia pollen revealed the presence of two main peaks: A broad asymmetrical component of a `bilayer' lineshape and a much narrower symmetrical component originating from phosphorus compounds undergoing rapid isotropic motion. From (a) ³¹P-NMR experiments on the hydrated total pollen phospholipids, (b) saturation transfer ³¹P-NMR experiments, and (c) the fraction of lipid phosphate in the pollen, it can be concluded that the great majority of the endogenous phospholipids are arranged in extended bilayers in which the lipid phosphates undergo fast (τ_c < 10⁻⁶ second) long axis rotation. This bilayer arrangement of phospholipids was observed in the pollen down to hydration levels of at least 10.9% moisture content. At the lowest level of pollen hydration examined (5.2%) the ³¹P-NMR spectrum had a solid state lineshape demonstrating that all the phosphorus-containing compounds (including the phospholipids) were virtually immobile.