关于上下视野不对称性的研究

该研究就国内外对上下视野不对称性的研究成果做了详细的阐述,主要包括上下视野的定义、上下视野不对称性的行为和神经机制方面的研究成果及当前所面临的问题,并在文章的最后提出自己的观点。     

腹侧通路与背侧通路在词汇阅读中的作用

腹侧通路与背侧通路是视觉加工的两条通路。随着认知神经科学的发展,研究发现腹侧和背侧通路与词汇阅读有关。其中腹侧通路与词汇识别有关,背侧通路与阅读的关系比较复杂。本文简要回顾了两条通路在词汇阅读中的作用。     

视觉的知觉-动作双系统理论中的论争

视觉的知觉-动作双系统理论认为,视觉的腹侧和背侧通路是两个独立系统,功能分别为表征世界和指导动作,相对应的视觉加工是彼此分离的。有关两条通路之间关系的其他观点可归结为两类：一类否认这种分工,另一类强调两个系统能相互影响。首先评述各种理论的核心问题、实验证据和贡献,进而分析视觉加工发生在一个特定系统的条件,得出的结论是：两个系统之间的功能划分是相对的,并因此导致了视觉加工的多变性。     

应用动态因果模型研究阅读神经网络背、腹侧通路的协作机制

在神经网络的最新取向下, 探讨阅读脑机制中背侧和腹侧通路的协作机制, 是解决语言认知神经科学多个理论问题共同面临的焦点。本项目拟通过两个脑功能成像实验, 建构汉字阅读的动态因果模型, 系统地考察汉字阅读的神经网络, 以及阅读网络中背、腹侧通路的协作机制。实验一利用快速适应实验范式的优点, 识别和考察汉字阅读涉及的认知成分所对应的功能脑区, 以及脑区联结形成的神经回路, 并建构汉字阅读的动态因果模型; 实验二进一步考察在刺激属性(语音和语义信息)和任务要求下阅读脑区的动态激活及相互作用。通过不同任务下的模型对比, 重点探讨阅读网络的脑区联结模式变化, 尤其是背、腹侧通路受刺激和任务影响时的协作机制。研究结果将为揭示阅读的神经生理模型、解决语言特异性脑区激活的争论等理论问题提供直接的证据, 还能为语言教学、阅读障碍矫治、以及临床应用提供理论基础与指导。     

视觉加工的双侧视野优势及其脑机制

等量的视觉任务呈现在双侧视野比仅仅呈现在单侧视野能够获得更好的任务表现, 这被称为双侧视野优势(bilateral field advantage BFA)。BFA产生于两个紧密连接的机制：枕叶视皮层内的竞争性相互作用及背侧额顶叶网络自上而下的注意调控。前者主要发生在V1–V4等与视网膜存在拓扑映射关系的视皮层区, 后者则主要涉及两侧的顶内沟、右侧楔前叶及额眼区。未来的研究可以进一步采用三维立体视觉材料探讨BFA, 考察它与其它视野效应间交互的脑机制, 同时也可尝试解决背侧额顶叶网络的各脑区在系统的功能连接方面尚存的争议。     

空间选择性注意在上下视野间的转移

本实验研究空间选择性注意在上下视野间的转移及其是否受知觉空间的影响。实验采用Posner的位置线索化实验范式和两种深度线索背景,测量分辨任务的反应时(RTs)。实验发现:线索有效时的反应时比线索无效时的反应时短,而且线索对上视野刺激的反应时的影响较大。知觉空间中的深度线索对于注意在上下视野中转移没有显著影响。这些结果表明,空间选择性注意在上下视野转移存在不对称性,并且主要由物理空间决定。     

示能性:基于镜像神经元视角的理解

示能性(affordance)概念解释了人的行为与物体功能之间互动、互补的关系。但是,有关示能性生理基础却很少被提及。镜像神经元的发现为示能性生理基础提供了可能的解释。文章根据研究将示能性分为结构示能性和功能示能性,探讨了不同示能性和镜像神经元之间的关系,并提出不同神经通路中的镜像神经元是示能性生理基础的结论。背-背侧分流中的镜像神经元是结构示能性的神经基础,而腹-背侧分流中的镜像神经元是功能示能性的神经基础。     

任务刺激的类型对任务切换的影响

为揭示联结竞争对任务切换的影响机制,我们采用了任务线索范式比较双向刺激与单向刺激对任务切换的影响。通过对数字任务和字母任务反应时的分析发现:在当前任务的刺激类型不同时,单向刺激的反应时明显小于双向刺激的反应时;在当前任务的刺激类型相同时,反应时差异不显著。这表明,联结竞争是通过当前任务的刺激影响任务切换的。     

“上下意象图式”对汉语成语感情色彩加工的影响

通过两个实验,考察了＂上下意象图式＂对汉语成语感情色彩加工的影响。实验一发现,成语感情色彩加工存在＂隐喻一致效应＂,褒义的成语呈现在屏幕上方加工得更快,贬义的成语呈现在屏幕下方加工得更快、更准。实验二消除了具体空间信息的影响,发现仅有抽象符号水平的联结,＂上＂、＂下＂概念不能影响汉语成语感情色彩的加工。研究结果支持隐喻理论和具身认知观。     

注意对半视野识别汉字的影响

用视觉外周呈现光点以控制注意的方法,对识别具体和抽象性汉字的脑功能偏侧化进行了研究。注意线索与刺激字在同侧视野呈现的间隔时间（ＳＯＡ）分为０、２９和５７ｍｓ。结果表明,具体性字在三种ＳＯＡ都表现出右视野左半球优势;而抽象性字在０ｍｓ两视野的识别成绩一样好。因此在偏侧视野识别汉字词中注意和脑结构因素似乎起着综合作用。     

Gaining the Upper Hand: Evidence of Vertical Asymmetry in Sex-Categorisation of Human Hands

Visual perception is characterised by asymmetries arising from the brain’s preferential response to particular stimulus types at different retinal locations. Where the lower visual field (LVF) holds an advantage over the upper visual field (UVF) for many tasks (e.g., hue discrimination, contrast sensitivity, motion processing), face-perception appears best supported at above-fixation locations (Quek & Finkbeiner, 2014a). This finding is consistent with Previc’s (1990) suggestion that vision in the UVF has become specialised for object recognition processes often required in ”extrapersonal” space. Outside of faces, however, there have been very few investigations of vertical asymmetry effects for higher-level objects. Our aim in the present study was, thus, to determine whether the UVF advantage reported for face-perception would extend to a nonface object – human hands. Participants classified the sex of hand images presented above or below central fixation by reaching out to touch a left or right response panel. On each trial, a briefly presented spatial cue captured the participant’s spatial attention to either the location where the hand was about to appear (valid cue) or the opposite location (invalid cue). We observed that cue validity only modulated the efficiency of the sex-categorisation response for targets in the LVLVF and not the UVF, just as we have reported previously for face-sex categorisation (Quek & Finkbeiner, 2014a). Taken together, the data from these studies provide some empirical support for Previc’s (1990) speculation that object recognition processes may enjoy an advantage in the upper-hemifield.     

Effects of Visual Information and Task Constraints on Intersegmental Coordination in Playground Swinging

The authors investigated how and to what extent visual information and associated task constraints are negotiated in the coordinative structure of playground swinging. Participants (N = 20) were invited to pump a swing from rest to a prescribed maximal amplitude under 4 conditions: normal vision, no vision, and 2 visual conditions involving explicit phasing constraints. In the latter conditions, participants were presented with a flow pattern consisting of a periodically expanding and contracting optical structure. They were instructed to phase the swing motion so that the forward turning point coincided with either the maximal size (enhanced optical flow) or the minimal size (reduced optical flow) of the presented flow pattern. Removal of visual information clearly influenced the swinging behavior, in that intersegmental coordination became more stereotyped, reflecting a general stiffening of the swinger. The conditions involving explicit phasing requirements also affected the coordination, but in an opposite way: The coordination became less stereotyped. The two phasing instructions had differential effects: The intersegmental coordination deviated more from normal swinging (i.e., without phasing constraints) when optical flow was enhanced than when it was reduced. Collectively, those findings show that visual information plays a formative role in the coordinative structure of swinging, in that variations of visual information and task constraints were accompanied by subtle yet noticeable changes in intersegmental coordination.     

Interactions of reading and semantics along the ventral visual processing stream

Converging evidence supports a distributed-plus-hub view of semantic processing, in which there are distributed modular semantic sub-systems (e.g., for shape, colour, and action) connected to an amodal semantic hub. Furthermore, object semantic processing of colour and shape, and lexical reading and identification, are processed mainly along the ventral stream, while action semantic processing occurs mainly along the dorsal stream. In Experiment 1, participants read a prime word that required imagining either the object or action referent, and then named a lexical word target. In Experiments 2 and 3, participants performed a lexical decision task (LDT) with the same targets as in Experiment 1, in the presence of foils that were legal nonwords (NW; Experiment 2) or pseudohomophones (PH; Experiment 3). Semantic priming was similar in effect size regardless of prime type for naming, but was greater for object primes than action primes for the LDT with PH foils, suggesting a shared-stream advantage when the task demands focus on orthographic lexical processing. These experiments extend the distributed-plus-hub model, and provide a novel paradigm for further research.     

The Effects of Relaxation and Postural Training on External Perception: Improvement of Visual Acuity, Visual Field, and Hearing Acuity

This study examined the effects of muscular relaxation and postural training on external perception using a visual acuity test, a visual field test, and a hearing acuity test. Eighteen undergraduate students were randomly assigned to experimental and control groups. The experimental group underwent muscular relaxation and postural training. Each subject in this group was administered the tests before and after the training. Each subject in the control group carried out the tests before and after participating in a 30-min conversation with the experimenter. On all three tests, the experimental group improved significantly more than the control group.     

Effects of Goal Type on Performance,Task Interest,and Affect Over Time1

The purpose of this study was to increase understanding regarding the effects of goal-setting practices on a wide range of dependent variables over time. Goal type (control group, quality goal, quantity goal, and dual goal) was manipulated across 3 time periods. Goal × Time interactions were predicted such that quantity, effort, task interest, and positive affect would initially be low, but by later trials would be higher in the quantity and dual-goal conditions compared to the quality goal and control groups. Quality was expected to be greatest in the quality goal condition and to be relatively constant over time. Participants (N= 80) were undergraduates at a large midwestern university. Results indicated some support for our hypotheses in that Goal × Time interactions were found for quantity produced, rated effort, task interest, and positive affect.     

Interaction of Tremor and Magnification in a Motor Performance Task With Visual Feedback

In this study, the interaction between increased gain in the visual feedback loop and motor control of the periphery was investigated. Participants (N = 15) were asked to maintain a constant finger position while they used magnified visual feedback. The measure of the accuracy of each trial was the standard deviation (trial error) of the finger position. Trials performed under magnification had lower trial errors than trials without magnification. The change in trial error between trials with and without magnification proved greater than the difference between trials at any 2 magnifications. In contrast, the differences between individual subjects were often greater than the differences between performances at individual magnifications. At higher magnifications, performance seemed to be limited by the tremor; the ratio of trial error to tremor intensity was constant. When applied to microsurgery, the present results accord with those found in earlier research, including investigations that have found that the level of magnification used in microsurgery is not the most significant factor in achieving good results and that tremor is the limiting factor in microsurgical tasks.     

Specificity of Learning in a Video-Aiming Task: Modifying the Salience of Dynamic Visual Cues

The authors investigated whether the salience of dynamic visual information in a video-aiming task mediates the specificity of practice. Thirty participants practiced video-aiming movements in a full-vision, a weak-vision, or a target-only condition before being transferred to the target-only condition without knowledge of results. The full- and weak-vision conditions resulted in less endpoint bias and variability in acquisition than did the target-only condition. Going from acquisition to transfer resulted in a large increase in endpoint variability for the full-vision group but not for the weak-vision or target-only groups. Kinematic analysis revealed that weak dynamic visual cues do not mask the processing of other sources of afferent information; unlike strong visual cues, weak visual cues help individuals calibrate less salient sources of afferent information, such as proprioception.