人手指振动触觉感知的短时记忆特性

本文旨在探究人手指振动触觉感知的短时记忆特性。采用自制振动触觉表达装置,在20名20～30岁被试(10男,10女)首先进行了一项回忆性实验,确定了手指振动强度触觉感知的记忆容量,然后在该范围内进行了再认性实验,对人手指振动强度触觉感知的再认正确率和被试反应时间进行了分析,得到了以下几个重要特性:(1)人手指振动触觉记忆容量为4±1;(2)振动强度间隔越大,手指振动强度记忆容量越大;(3)振动持续时间过长或过短都会导致振动记忆容量减少,男性最佳持续时间为400 ms,女性为300 ms;(4)振动刺激系列越长,再认正确率越低,反应时间越长;(5)振动刺激序列按强度递增或递减的顺序排布要比按混乱的顺序排布更容易记忆;(6)手指振动触觉感知的短时记忆信息提取是按照逐个进行比较的系列扫描方式进行的。这些实验结果有助于了解人手指指尖触觉感知特性,为触觉反馈技术的研究提供生理学依据。     

人手腕部振动强度触觉感知的短时记忆特性

本文设计了一个回忆性实验和一个再认性实验,使用自行研制的振动触觉表达装置作为实验平台,研究了人手腕部的振动强度触觉感知短时记忆特性。首先通过回忆性实验确定了人手腕部的振动强度触觉感知平均记忆容量(简称振动强度记忆容量),然后在记忆容量范围内又进行了再认性实验,对人手腕部的振动触觉再认正确率和反应时进行了数据分析。通过实验,我们得到人手腕部振动强度触觉感知相关的5个重要特性:(1)振动强度记忆容量为3±1;(2)振动触觉刺激的振动强度离散间隔越大,振动强度记忆容量就越大;(3)振动强度记忆容量具有显著的性别差异;(4)振动触觉短时记忆信息的提取是逐个比较的遍历扫描过程;(5)触觉感知再认正确率和反应时表现均远逊于视觉和听觉。这些实验结果有助于充分了解人体的触觉感知特性,是振动触觉表达编码方案的重要设计依据。     

一种基于可穿戴器件触觉感知信息的盲人虚拟视觉导航系统

目的 全球视力受损或失明人数已超2亿，长期以来各类人工视觉系统被广泛研究。人工视觉系统的研发主要有两种技术路径，第一种是各类植入式人工视觉装置，第二种是各类非植入式、可穿戴装置。本文展示了一种非植入式、基于可穿戴头部触觉激发装置的系统原型，能够帮助盲人和视觉障碍者完成行走等复杂任务。方法 该系统采集受试者周边环境图像信息并无线传输到后台，操作人员分析处理图像信息后，将指令以触觉编码形式无线传输到头套等可穿戴装置，由驱动电路激发多点位头部触觉，从而为受试者提供准确的行动指令。系统并辅助以语音信息，让其了解更多道路状况和环境信息。结果 用原型系统对5名（2男3女）在读大学生健康志愿者和1名年轻盲症患者（男）进行实验。结果表明，原型系统充分利用了头部对前后左右的天然区分能力和对触觉的快速反应，具备直行、左右调整、转弯等明确指令功能。受试者对指令的响应时间约0.5 s，直线行走约7 m距离的偏差量标准差平均值相比未佩戴装置的情况下降低到（16±10）cm。结论 该系统可隐蔽、准确地提供环境图像信息，有效帮助视觉障碍人士完成行走、避让障碍物、上台阶、进入咖啡厅等公共场所、桌上取物等日常活动，达到了预期目标。今后对原型系统作进一步完善，特别是小型化、智能芯片化，把触觉装置制成颈环、腰带、手环、脚环等，将能够广泛应用于盲人出行辅助、夜间野外旅行、深海潜水等多种工作场景。     

一种可控电磁触觉刺激器的研制

介绍了一种可控电磁触觉刺激装置的制作方法, 该装置能够与电子计算机记录系统同步地工作,并且能够控制触压刺激的速度、时程及强度。文中对该装置的工作原理、构造及应用情况分别作了介绍。     

长江口中华鲟幼鱼感觉器官在摄食行为中的作用

中华鲟为我国一级保护水生野生动物,其幼鱼生活史研究尚有许多空白。本文通过分别封闭中华鲟幼鱼不同感觉器官（包括视觉、嗅觉、触觉、侧线感觉、电感觉等）,研究了这些感觉器官在中华鲟幼鱼摄食行为中的重要性,旨存为改进中华鲟幼鱼的保护措施和人工培育技术提供科学依据。63尾实验鱼于2006年5—6月采集于长江口水域,实验鱼在试验开始前暂养适应2周,实验设计7个实验组和1个对照组,实验期水温为24．5—27．0℃。实验结果显示：封闭视觉、侧线感觉和电感觉器官后幼鱼的摄食量与正常幼鱼（对照组）无显著性差异（P〉0．05）。封闭嗅觉幼鱼的摄食量只有正常幼鱼的34．76％。封闭触觉幼鱼的摄食量只有正常幼鱼的73．80％。同一时间封闭嗅觉和触觉后,幼鱼的摄食量仅为正常幼鱼的17．01％。因此,可以推断嗅觉和触觉在中华鲟幼鱼觅食过程中起着主要的作用。     

《科学一报告》：能延伸到纳米尺度的触觉极限

2013年9月的Scientific Reports上发表的一项研究显示，人类手指能够区分有小至13纳米凸起图案的表面和没有图案的表面。这一发现表明，人类的触觉极限也许能延伸到纳米尺度。     

虚拟现实技术应用于运动障碍康复的研究

概述了近年来虚拟现实技术在运动障碍康复中的应用。介绍了该技术在运动障碍康复领域的四个重点研究方向：康复机器人、虚拟人、基于触觉反馈和力反馈的虚拟现实康复平台以及游戏机Wii的应用和新进展。最后总结了虚拟现实应用于运动障碍康复的优势及面临的主要挑战。     

药物提高触觉感

科学家在没有使用药物的情况下提高了人类手指触摸的感觉 ,然后再使用药物来加重或是减少这种临时增加的触觉感。一项新研究表明 ,类似的皮肤刺激和药物治疗的共同作用也许最终会让中风患者自己扣钮扣 ,或弹奏出更好的曲目。论文的主要作者 HubertDinse解释说 ,指尖的刺激和药物能暂时性地对部分人类的大脑进行改组。这种被称为共同作用的刺激搅乱了连结神经元的神经键。通过改变神经键间的连结性 ,共同刺激增加了在触觉信息过程中发挥作用的神经元。科学家的研究表明 ,安非他命能够双倍地增加触觉的精度 ,触觉的精度被称为知觉学习。当使…     

新生期触觉刺激和母婴分离对雌性大鼠成年后的焦虑和情绪记忆的影响

采用split-litter法对仔鼠进行分组和处理,共5组NTS组(未经实验人员抓握和标记),PND2—9TS组和PND10—17TS组(分别在仔鼠出生后的2—9天、10—17天,每天短暂抓握和标记仔鼠),PND2—9MS组和PND10—17MS组(分别在仔鼠出生后的2—9天、10—17天,除了按TS组相同方式抓握并在不同部位标记外,每天把仔鼠与母鼠分离1h)。待雌鼠成年后,进行明/暗箱测试和一次性被动回避反应测试。结果发现与NTS组相比,PND2—9TS组和PND10—17TS组的雌鼠在明/暗箱测试中停留于明室的累计时间明显较长,在被动回避作业中的重测试潜伏期也明显较长,表明新生期的触觉刺激经历减少雌性大鼠成年后在新异环境中的焦虑,并改善情绪记忆。与相应TS组相比,MS处理组的所有行为指标都无显著性差异,说明短时间母婴分离对雌鼠成年后的焦虑和情绪记忆无明显影响。结果提示,新生期的触觉刺激和母婴分离经历对仔鼠神经系统的发育产生不同的长期效应。     

探索人类温度感觉和触觉机制——解读2021年诺贝尔生理学或医学奖

2021年诺贝尔生理学或医学奖授予了美国科学家朱利叶斯和帕塔博蒂安,以表彰他们在研究痛觉和触觉形成机制中的贡献。通过生物信息学分析、cDNA文库筛选和基因敲减等现代分子生物技术,他们发现了介导机体温度、痛觉和触觉感受的TRPV1和Piezo1/2受体分子及其作用机制,为揭示人类感知和认识世界的原理,迈出了坚实的一步。     

Haptic object perception: spatial dimensionality and relation to vision

Enabled by the remarkable dexterity of the human hand, specialized haptic exploration is a hallmark of object perception by touch. Haptic exploration normally takes place in a spatial world that is three-dimensional; nevertheless, stimuli of reduced spatial dimensionality are also used to display spatial information. This paper examines the consequences of full (three-dimensional) versus reduced (two-dimensional) spatial dimensionality for object processing by touch, particularly in comparison with vision. We begin with perceptual recognition of common human-made artefacts, then extend our discussion of spatial dimensionality in touch and vision to include faces, drawing from research on haptic recognition of facial identity and emotional expressions. Faces have often been characterized as constituting a specialized input for human perception. We find that contrary to vision, haptic processing of common objects is impaired by reduced spatial dimensionality, whereas haptic face processing is not. We interpret these results in terms of fundamental differences in object perception across the modalities, particularly the special role of manual exploration in extracting a three-dimensional structure.     

Experimental Research Examining How People Can Cope with Uncertainty Through Soft Haptic Sensations

Human beings are constantly surrounded by uncertainty and change. The question arises how people cope with such uncertainty. To date, most research has focused on the cognitive strategies people adopt to deal with uncertainty. However, especially when uncertainty is due to unpredictable societal events (e.g., economical crises, political revolutions, terrorism threats) of which one is unable to judge the impact on one’s future live, cognitive strategies (like seeking additional information) is likely to fail to combat uncertainty. Instead, the current paper discusses a method demonstrating that people might deal with uncertainty experientially through soft haptic sensations. More specifically, because touching something soft creates a feeling of comfort and security, people prefer objects with softer as compared to harder properties when feeling uncertain. Seeking for softness is a highly efficient and effective tool to deal with uncertainty as our hands are available at all times. This protocol describes a set of methods demonstrating 1) how environmental (un)certainty can be situationally activated with an experiential priming procedure, 2) that the quality of the softness experience (what type of softness and how it is experienced) matters and 3) how uncertainty can be reduced using different methods.     

Haptic interaction with virtual objects

This paper considers interaction of the human arm with “virtual” objects simulated mechanically by a planar robot. Haptic perception of spatial properties of objects is distorted. It is reasonable to expect that it may be distorted in a geometrically consistent way. Three experiments were performed to quantify perceptual distortion of length, angle and orientation. We found that spatial perception is geometrically inconsistent across these perceptual tasks. Given that spatial perception is distorted, it is plausible that motor behavior may be distorted in a way consistent with perceptual distortion. In a fourth experiment, subjects were asked to draw circles. The results were geometrically inconsistent with those of the length perception experiment. Interestingly, although the results were inconsistent (statistically different), this difference was not strong (the relative distortion between the observed distributions was small). Some computational implications of this research for haptic perception and motor planning are discussed. Received: 12 February 1996 /Accepted in revised form: 6 May 1999     

Delays in Admittance-Controlled Haptic Devices Make Simulated Masses Feel Heavier

In an admittance-controlled haptic device, input forces are used to calculate the movement of the device. Although developers try to minimize delays, there will always be delays between the applied force and the corresponding movement in such systems, which might affect what the user of the device perceives. In this experiment we tested whether these delays in a haptic human-robot interaction influence the perception of mass. In the experiment an admittance-controlled manipulator was used to simulate various masses. In a staircase design subjects had to decide which of two virtual masses was heavier after gently pushing them leftward with the right hand in mid-air (no friction, no gravity). The manipulator responded as quickly as possible or with an additional delay (25 or 50 ms) to the forces exerted by the subject on the handle of the haptic device. The perceived mass was ~10% larger for a delay of 25 ms and ~20% larger for a delay of 50 ms. Based on these results, we estimated that the delays that are present in nowadays admittance-controlled haptic devices (up to 20ms) will give an increase in perceived mass which is smaller than the Weber fraction for mass (~10% for inertial mass). Additional analyses showed that the subjects’ decision on mass when the perceptual differences were small did not correlate with intuitive variables such as force, velocity or a combination of these, nor with any other measured variable, suggesting that subjects did not have a consistent strategy during guessing or used other sources of information, for example the efference copy of their pushes.     

Novel Simulation Tools for Materials Engineering Education

Abstract

A novel simulation interface is being developed as an educational tool to help students better understand fundamentals of materials science. This interface makes use of virtual reality (VR) technology consisting of PC-based graphics and a force-feedback haptic device. Visualization of atomistic processes with simultaneous tactile sensation via the haptic provides a powerful method for understanding complex phenomena that are otherwise difficult to comprehend. Modules are described that allow students to interactively explore interatomic bonding and single-atom diffusion through materials.     

How haptic size sensations improve distance perception

Determining distances to objects is one of the most ubiquitous perceptual tasks in everyday life. Nevertheless, it is challenging because the information from a single image confounds object size and distance. Though our brains frequently judge distances accurately, the underlying computations employed by the brain are not well understood. Our work illuminates these computions by formulating a family of probabilistic models that encompass a variety of distinct hypotheses about distance and size perception. We compare these models' predictions to a set of human distance judgments in an interception experiment and use Bayesian analysis tools to quantitatively select the best hypothesis on the basis of its explanatory power and robustness over experimental data. The central question is: whether, and how, human distance perception incorporates size cues to improve accuracy. Our conclusions are: 1) humans incorporate haptic object size sensations for distance perception, 2) the incorporation of haptic sensations is suboptimal given their reliability, 3) humans use environmentally accurate size and distance priors, 4) distance judgments are produced by perceptual "posterior sampling". In addition, we compared our model's estimated sensory and motor noise parameters with previously reported measurements in the perceptual literature and found good correspondence between them. Taken together, these results represent a major step forward in establishing the computational underpinnings of human distance perception and the role of size information.     

Hand preferences for a haptic searching task by tufted capuchins (Cebus apella)

We tested the effects of a haptic search task on hand preferences in capuchins(Cebus apella) and compare this situation to a visual by guided reaching task. In the haptic task, 21 monkeys searched for sunflower seeds on the top or side surfaces of 12 objects. A left-hand preference emerged at the group level, suggesting a greater involvement of the right hemisphere. The percentage of preferred hand usage and the direction of the preference were influenced by both sex and age of the subjects: adult males tended to be less lateralized than the other groups of subjects were. Shape had an insignificant effect on the direction of hand preferences or on the percentage of preferred hand use. No lateral bias emerge in the visually guided reaching task, and the percentage of left-hand usage fell significantly across tasks, demonstrating that the haptic demands of the task enhance the use of the left hand at the group level. We discuss these results with regard to current theories on manual lateralization in nonhuman primates.     

Haptic Discrimination of Distance

While quite some research has focussed on the accuracy of haptic perception of distance, information on the precision of haptic perception of distance is still scarce, particularly regarding distances perceived by making arm movements. In this study, eight conditions were measured to answer four main questions, which are: what is the influence of reference distance, movement axis, perceptual mode (active or passive) and stimulus type on the precision of this kind of distance perception? A discrimination experiment was performed with twelve participants. The participants were presented with two distances, using either a haptic device or a real stimulus. Participants compared the distances by moving their hand from a start to an end position. They were then asked to judge which of the distances was the longer, from which the discrimination threshold was determined for each participant and condition. The precision was influenced by reference distance. No effect of movement axis was found. The precision was higher for active than for passive movements and it was a bit lower for real stimuli than for rendered stimuli, but it was not affected by adding cutaneous information. Overall, the Weber fraction for the active perception of a distance of 25 or 35 cm was about 11% for all cardinal axes. The recorded position data suggest that participants, in order to be able to judge which distance was the longer, tried to produce similar speed profiles in both movements. This knowledge could be useful in the design of haptic devices.     

Is there a ‘plenhaptic’ function?

One approach to gauge the complexity of the computational problem underlying haptic perception is to determine the number of dimensions needed to describe it. In vision, the number of dimensions can be estimated to be seven. This observation raises the question of what is the number of dimensions needed to describe touch. Only with certain simplified representations of mechanical interactions can this number be estimated, because it is in general infinite. Organisms must be sensitive to considerably reduced subsets of all possible measurements. These reductions are discussed by considering the sensing apparatuses of some animals and the underlying mechanisms of two haptic illusions.     

Haptic categorical perception of shape

Categorization and categorical perception have been extensively studied, mainly in vision and audition. In the haptic domain, our ability to categorize objects has also been demonstrated in earlier studies. Here we show for the first time that categorical perception also occurs in haptic shape perception. We generated a continuum of complex shapes by morphing between two volumetric objects. Using similarity ratings and multidimensional scaling we ensured that participants could haptically discriminate all objects equally. Next, we performed classification and discrimination tasks. After a short training with the two shape categories, both tasks revealed categorical perception effects. Training leads to between-category expansion resulting in higher discriminability of physical differences between pairs of stimuli straddling the category boundary. Thus, even brief training can alter haptic representations of shape. This suggests that the weights attached to various haptic shape features can be changed dynamically in response to top-down information about class membership.