感觉-运动系统参与隐喻理解的认知神经机制

最近十几年的研究发现,人们常借助感觉-运动经验来获取具体概念,表明感觉-运动系统与言语系统存在紧密联系.隐喻是借助具体概念描述抽象概念的常见修辞方式,因此,探讨感觉-运动系统在隐喻理解中的作用有助于解决抽象概念形成与理解的科学问题,进一步阐明感觉-运动系统与言语系统的关系.本文总结了研究感觉-运动系统参与隐喻理解所采用的实验范式,归纳了感觉-运动系统参与隐喻理解的影响因素,综述了与感觉通道、动作控制和执行有关的脑区参与隐喻理解时的认知神经机制,并且在此基础上,提出了以下观点:感觉运动经验有选择性地参与隐喻理解,理解过程依赖与感觉-运动有关脑区的激活;感觉运动经验的模拟不是快速即时的,受到语言理解策略的影响;在"具身提取理论"的框架下,"感觉运动模拟隐喻理论"能进一步说明感觉-运动系统与隐喻的相互作用.最后结合研究现状,从研究方法、语法规则、言语习得、运动障碍这四个方面提出了未来研究展望.     

概率类别学习的认知神经机制

概率类别学习是探讨人们如何习得线索与结果之间的"概率"关系.研究者借助天气预报等任务,探讨了概率类别学习的认知策略、无意识性及其与工作记忆和注意的关系,并借助脑成像技术和脑损伤病人,探讨了基底神经节、内侧颞叶、前额叶和顶叶等脑区在概率类别学习中的作用.但是,由于概率类别学习涉及内隐和外显学习系统的分离问题,目前对其相关研究结果和理论解释还存在很大争议,概率类别学习的认知神经机制仍有待进一步研究.     

内侧前额叶与社会认知

早期的研究表明杏仁核、前额叶、颞上沟、前扣带回等与人类的社会认知活动有关;随着多种新技术的应用。越来越多的研究发现其它一些脑区结构(如岛叶、基底节、白质等)也与社会认知和行为有关。本文综述了内侧前额叶在社会认知中的作用,重点介绍了内侧前额叶在心灵理论、情绪认知、社会推理与决策、道德判断、自我认知等社会认知活动中的作用。未来研究希望能从整体和动态上认识内侧前额叶在社会认知活动中的作用。     

综述: 渐近优先性及其机制

对渐近信号的优先加工被称为渐近优先性,该效应普遍存在于人类和动物的视觉、听觉和跨感觉通道中.人类神经影像学研究发现负责加工渐近信号的脑区涉及一个大规模相互协作和沟通的分布式神经网络,包括颞上沟、颞顶叶连接处以及一些运动区.对多种动物的细胞水平研究也发现了对渐近信号选择性敏感的神经元和神经通路.威胁论、注意捕获理论和自动加工理论从不同角度解释了渐近优先性产生的原因.未来研究可进一步考察刺激的社会、情绪等属性对渐近优先性的影响,探索多通道渐近渐远信息的整合和注意分配机制.     

渐近优先性及其机制

对渐近信号的优先加工被称为渐近优先性,该效应普遍存在于人类和动物的视觉、听觉和跨感觉通道中.人类神经影像学研究发现负责加工渐近信号的脑区涉及一个大规模相互协作和沟通的分布式神经网络,包括颞上沟、颞顶叶连接处以及一些运动区.对多种动物的细胞水平研究也发现了对渐近信号选择性敏感的神经元和神经通路.威胁论、注意捕获理论和自动加工理论从不同角度解释了渐近优先性产生的原因.未来研究可进一步考察刺激的社会、情绪等属性对渐近优先性的影响,探索多通道渐近渐远信息的整合和注意分配机制.     

纹状体神经通路与运动调控

纹状体(striatum)是机体运动中枢的关键组成部分,对机体随意运动、非意识性运动、肌张力、身体姿态、精细运动等调节均发挥重要作用。纹状体功能异常导致运动失调:一类为运动减少,肌张力亢进,如帕金森病;另一类为运动过多,肌张力不足,如舞蹈病。一般认为,纹状体接收大脑运动皮层传来的运动相关信号,经其加工处理后,经丘脑返传回运动皮层,最终由运动皮层发出运动执行信号,经锥体系完成运动。可见,纹状体的运动调控功能有赖于复杂的神经通路系统。本文综述近几年来有关纹状体神经通路与运动调控的研究进展,以期更深入理解纹状体运动调控神经机制及其与临床疾病的关系。     

主动运动和被动运动的镇痛效果及其镇痛机制

主动运动和被动运动可以有效缓解各种急性疼痛和慢性疼痛,且主动运动诱发的镇痛效果强于运动参数相似的被动运动.文章在讨论运动镇痛机制的基础上,探讨了主、被动运动镇痛效果存在差异的原因.具体来说,通过比较两种运动传导运动信息的下行通路和传导躯体感觉/本体感觉的上行通路,论述了主、被动运动在生理(外周神经系统和中枢神经系统)和心理(情绪和认知)层面上镇痛机制的异同.由于被动运动缺少运动下行控制且肌肉激活程度小,其在外周镇痛物质含量和皮层水平上对疼痛的调控弱于主动运动.此外,被动运动相比主动运动不易诱发积极情绪,较难转移对疼痛的注意力,缺乏身体掌控感并拥有较低的身体归属感,进而导致较弱的镇痛效果.最后,文章指出了目前本领域研究的局限性,并对运动镇痛未来的研究方向和方法提出了建议.     

多方式认知功能成像研究进展

对大脑结构和功能的深入研究要求认知功能成像技术同时具有高时间分辨率和高空间分辨率.多方式认知功能成像通过不同成像技术fMRI/PET和EEG/MEG的结合,能够同时在空间定位和时间过程上研究大脑认知活动的动态过程.多方式认知功能成像已经被成功地应用于选择性注意、视觉通路、随意运动和语义加工等的研究,并揭示了相关大脑活动的空间和时间特征.今后的研究将进一步提高多方式认知功能成像的时空分辨率和准确性,以更深入地探索认知功能的神经机制.     

癌细胞运动与迁移的分子机制

癌细胞运动和迁移的分子机制远较我们想象的复杂,癌细胞的运动和迁移性和接触性刺激相应答的细胞膜突起形成所启动的多步骤过程的结果.人们普遍想相信,片状伪足在驱动癌细胞迁移中起着主要作用,它通过附着在基底膜上而产生拉动细胞体向前的力量.近来的研究证明,切丝蛋白是癌细胞运动和迁移的一个重要调节因子, 切丝蛋白的局部激活可以诱导片状伪足的形成,并设定细胞运动方向.此外,成束蛋白.Arp2/3复合物、Cdc42、LIM激酶和黏着斑激酶常常协同调节癌细胞的运动和迁移.虽然调节癌细胞运动和迁移的信号通路和分子机制尚未完全阐明,但现有的资料清楚地表明,抑制癌细胞的迁移性将可能成为抑制恶性肿瘤生长和扩散的一个有用的策略.     

运动对时距知觉的影响及其神经机制

在运动过程中,时距知觉的能力非常重要,能帮助个体对时长进行判断及对事件的发生做出预测和准备.近年来,越来越多的研究发现运动本身会直接影响个体的时距知觉.本文分别从运动参数、运动阶段、视觉运动刺激和运动有关的个体因素四个方面梳理了运动对时距知觉产生影响的行为学证据.目前已经有大量研究从不同角度证明,大脑运动系统组成了支持主观时间知觉的神经网络,并且编码和参与了人类的时距知觉.运动作用于时距知觉的理论机制可以基于内部时钟模型的理论框架并进而从感觉运动信息的交互、运动对唤醒状态的改变及具身认知理论三个角度予以解释.未来研究需要关注运动对不同单位级别时距知觉的影响,测评运动状态下时距知觉的研究范式及技术手段等多个方面进行思考和推进,从而更好地揭示运动如何调节时距知觉过程及其作用机制.还应该结合竞技运动项目特点,为减少运动中时距知觉误差和提高运动员时距知觉能力提供帮助与指导.     

Direct evidence for encoding of motion streaks in human visual cortex

Temporal integration in the visual system causes fast-moving objects to generate static, oriented traces (‘motion streaks’), which could be used to help judge direction of motion. While human psychophysics and single-unit studies in non-human primates are consistent with this hypothesis, direct neural evidence from the human cortex is still lacking. First, we provide psychophysical evidence that faster and slower motions are processed by distinct neural mechanisms: faster motion raised human perceptual thresholds for static orientations parallel to the direction of motion, whereas slower motion raised thresholds for orthogonal orientations. We then used functional magnetic resonance imaging to measure brain activity while human observers viewed either fast (‘streaky’) or slow random dot stimuli moving in different directions, or corresponding static-oriented stimuli. We found that local spatial patterns of brain activity in early retinotopic visual cortex reliably distinguished between static orientations. Critically, a multivariate pattern classifier trained on brain activity evoked by these static stimuli could then successfully distinguish the direction of fast (‘streaky’) but not slow motion. Thus, signals encoding static-oriented streak information are present in human early visual cortex when viewing fast motion. These experiments show that motion streaks are present in the human visual system for faster motion.     

A multilayer neural network model for perception of rotational motion

A multilayer neural nerwork model for the perception of rotational motion has been developed usingReichardt's motion detector array of correlation type, Kohonen's self-organized feature map and Schuster-Wagner's oscillating neural network. It is shown that the unsupervised learning could make the neurons on the second layer of the network tend to be self-organized in a form resembling columnar organization of selective directions in area MT of the primate's visual cortex. The output layer can interpret rotation information and give the directions and velocities of rotational motion. The computer simulation results are in agreement with some psychophysical observations of rotation-al perception. It is demonstrated that the temporal correlation between the oscillating neurons would be powerful for solving the "binding problem" of shear components of rotational motion.     

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.     

Self-recognition of avatar motion: how do I know it's me?

When motion is isolated from form cues and viewed from third-person perspectives, individuals are able to recognize their own whole body movements better than those of friends. Because we rarely see our own bodies in motion from third-person viewpoints, this self-recognition advantage may indicate a contribution to perception from the motor system. Our first experiment provides evidence that recognition of self-produced and friends' motion dissociate, with only the latter showing sensitivity to orientation. Through the use of selectively disrupted avatar motion, our second experiment shows that self-recognition of facial motion is mediated by knowledge of the local temporal characteristics of one's own actions. Specifically, inverted self-recognition was unaffected by disruption of feature configurations and trajectories, but eliminated by temporal distortion. While actors lack third-person visual experience of their actions, they have a lifetime of proprioceptive, somatosensory, vestibular and first-person-visual experience. These sources of contingent feedback may provide actors with knowledge about the temporal properties of their actions, potentially supporting recognition of characteristic rhythmic variation when viewing self-produced motion. In contrast, the ability to recognize the motion signatures of familiar others may be dependent on configural topographic cues.     

Neural circuits underlying motor facilitation during observation of implied motion

Abstract

In the present study we used single and paired-pulse Transcranial Magnetic Stimulation (TMS) to evaluate the effect of implied motion on primary motor cortex microcircuits. We found that observation of the implied motion of a static image increases MEP amplitude and reduces short-interval intracortical inhibition (SICI), without significant modulation of intracortical facilitation and sensory-motor integration. Our results add to the existing literature on the activation of the observation-execution matching system and describe a selective modulation of GABAergic cortical microcircuits during observation of implied motion.     

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.     

A novel approach to predicting human ingress motion using an artificial neural network

Due to the increased availability of digital human models, the need for knowing human movement is important in product design process. If the human motion is derived rapidly as design parameters change, a developer could determine the optimal parameters. For example, the optimal design of the door panel of an automobile can be obtained for a human operator to conduct the easiest ingress and egress motion. However, acquiring motion data from existing methods provides only unrealistic motion or requires a great amount of time. This not only leads to an increased time consumption for a product development, but also causes inefficiency of the overall design process. To solve such problems, this research proposes an algorithm to rapidly and accurately predict full-body human motion using an artificial neural network (ANN) and a motion database, as the design parameters are varied. To achieve this goal, this study refers to the processes behind human motor learning procedures. According to the previous research, human generate new motion based on past motion experience when they encounter new environments. Based on this principle, we constructed a motion capture database. To construct the database, motion capture experiments were performed in various environments using an optical motion capture system. To generate full-body human motion using this data, a generalized regression neural network (GRNN) was used. The proposed algorithm not only guarantees rapid and accurate results but also overcomes the ambiguity of the human motion objective function, which has been pointed out as a limitation of optimization-based research. Statistical criteria were utilized to confirm the similarity between the generated motion and actual human motion. Our research provides the basis for a rapid motion prediction algorithm that can include a variety of environmental variables. This research contributes to an increase in the usability of digital human models, and it can be applied to various research fields.     

一种感知视觉运动信息的简化脑模型

视觉运动信息的感知过程,包括从局域运动检测到对模式整体运动的感知过程.我们以蝇视觉系统的图形-背景相对运动分辨的神经回路网络为基本框架,采用初级运动检测器的六角形阵列作为输入层,构造了一种感知视觉运动信息的简化脑模型,模拟了运动信息应该神经计算模型各个层次上的处理.该模型对差分行为实验结果作出了正确预测.本文并对空间生理整合的神经机制作了讨论.     

The hierarchy of directional interactions in visual motion processing

It is well known that context influences our perception of visual motion direction. For example, spatial and temporal context manipulations can be used to induce two well-known motion illusions: direction repulsion and the direction after-effect (DAE). Both result in inaccurate perception of direction when a moving pattern is either superimposed on (direction repulsion), or presented following adaptation to (DAE), another pattern moving in a different direction. Remarkable similarities in tuning characteristics suggest that common processes underlie the two illusions. What is not clear, however, is whether the processes driving the two illusions are expressions of the same or different neural substrates. Here we report two experiments demonstrating that direction repulsion and the DAE are, in fact, expressions of different neural substrates. Our strategy was to use each of the illusions to create a distorted perceptual representation upon which the mechanisms generating the other illusion could potentially operate. We found that the processes mediating direction repulsion did indeed access the distorted perceptual representation induced by the DAE. Conversely, the DAE was unaffected by direction repulsion. Thus parallels in perceptual phenomenology do not necessarily imply common neural substrates. Our results also demonstrate that the neural processes driving the DAE occur at an earlier stage of motion processing than those underlying direction repulsion.