Effects of Movement Duration and Visual Feedback on Visual and Proprioceptive Components of Prism Adaptation

While looking through laterally displacing prisms, subjects pointed sagittally 80 times at an objectively straight-ahead target, completing a reciprocal out-and-back pointing movement every 1, 3, or 6 s. Visual feedback was available early in the pointing movement or only late at the end of movement. Aftereffect measures of adaptive shift (obtained after every 10 pointing trials) showed adaptive change only in limb position sense (i.e., proprioceptive adaptation) when movement duration was 1 s, regardless of visual feedback condition; but as movement duration increased, adaptive change in the eye position sense (i.e., visual adaptation) increased while proprioceptive adaptation decreased, especially for the late visual feedback condition. Regardless of visual feedback condition, proprioceptive adaptation showed the maximal rate of growth with the 1-s movement duration, whereas visual adaptation showed maximal growth with the 6-s movement duration. These results provide additional support for a model of adaptive spatial mapping in which the direction of strategically flexible coordination (guidance) between eye and limb (and consequently the locus of adaptive spatial mapping) is jointly determined by movement duration and timing of visual feedback. An additional effect of movement duration is to determine the rate of discordant inputs. Maximal growth of adaptation occurs when the input rate matches the response time of the spatial mapping function.     

No Relationship Between Joint Position Sense and Force Sense at the Shoulder

In practice, a single test is used to quantify an individual's proprioception. Previous studies have not found a correlation between joint position sense (JPS) and force sense (FS), which are submodalities of proprioception. The purpose of the present study is to determine if root mean square (RMS) error in JPS and FS are related at the shoulder, controlling for external load and elevation angle. Active shoulder angle and force reproduction protocols were performed. No correlation was found between JPS and FS (r = –.019, p = .941) nor were any individual angle and load combinations significant. The main effect for angle in JPS was significant (p < .001). Follow-up contrast demonstrated a significant (p < .001) decrease in RMS error with increased elevation. A significant load by angle interaction was found for FS (p = .014). Follow-up simple effects tests by angle demonstrated RMS error decreased with load at 50° and 70° but not at 90°. By load, RMS error only decreased for 120% between 50° and 90°. JPS and FS demonstrate different behavior with load and angle. This differing behavior is more likely responsible for the lack of correlation than angle and load differences in JPS and FS protocols.     

空间再定向任务中心理表征的多样性——来自虚拟现实实验的证据

成人和儿童完成空间再定向的具体过程与内在机制一直是研究者们关注的问题,在空间中是否形成了关于环境的整体表征是其中的一个关键。研究者们的观点并不一致,研究结果也提供了不同的证据。使用传统的空间再定向任务在此问题上难以得到明确的结论。本研究采用虚拟现实技术,让被试在虚拟现实环境中观察所在空间,然后直接向被试呈现空间的俯视视角并要求完成位置再认。通过对正确率和反应时的模式分析,发现被试反应可以划分为三种类型：整体的、独立于视角的心理表征（各方向均为高正确率低反应时）;整体的、依赖于方向的心理表征（正确率和反应时在不同方向上差异显著）和视角匹配的心理表征（各方向上均为低正确率）。三种不同的表征形式在人群中同时存在,并且在同一个体身上表现出不稳定性。     

Effect of Force Sense to Active Joint Position Sense and Relationships between Active Joint Position Sense,Force Sense,Jumping and Muscle Strength

Abstract

We aimed to investigate the effect of external load on the joint position sense (JPS) accuracy and its relation to the target jump height. The present study also aimed to explore the relationship between force sense (FS) and maximum voluntary isometric contraction (MVIC). Participants’ MVIC levels were determined during the 45-degree knee extension task. Then, participants were asked to execute a knee JPS task with external load (EL-JPS) and with no-load (EL-JPS). To assess jumping accuracy participants were instructed to jump with their 50% of maximum jump height. Results indicated that EL-JPS error values were lower than NL-JPS. EL-JPS was correlated to jumping errors. However, the relationship between NL-JPS and jumping errors was not significant. A significant correlation was found between MVIC and FS errors.     

适应范式在人脸知觉研究中的应用

适应范式为考察各种心理现象或心理过程的机制提供了一条重要的途径。本文在简要介绍传统适应范式和功能性磁共振适应范式的基础上,重点回顾了它们在人脸知觉研究中的应用,提出人脸适应后效除源于尺寸和朝向等低、中水平物理信息的编码加工外,更多地基于身份和性别等高水平社会信息的编码,且其效应量依赖于高水平的基于标准的竞争性编码加工机制。对人脸类别属性的编码标准和时效性等问题仍有待进一步分析。     

Position Sense Dysfunction Affects Proximal and Distal Arm Joints in Children with Developmental Coordination Disorder

It is unclear, whether proprioceptive dysfunction in developmental coordination disorder (DCD) is localized affecting only specific joints or whether it is generalized affecting proximal and distal joints. Thus, this study assessed position sense acuity at the elbow and wrist in twenty children with DCD (age: 9–11 yrs.) using a joint position matching paradigm. Position sense bias (systematic error) at either joint was not significantly higher in DCD children when compared to typically developing children (TD). However, DCD children exhibited significantly lower position sense precision (random error) than TD children at both elbow and wrist. That is, response reliability to proprioceptive stimuli is altered in DCD. Our findings are consistent with a view that proprioceptive dysfunction in DCD is generalized in nature.     

Modulation of Gait During Visual Adaptation to Dark

The authors investigated the modulation of gait during dark adaptation. Twenty-five women (mean age = 72 years, SD = 5 years) walked back and forth on an arbitrarily uneven walkway during normal lighting at speeds ranging from slow to fast. Participants then performed 20 trials at preferred speed after sudden reduction of lighting; the authors compared those trials with point estimates at equivalent speeds representing normal lighting. The authors estimated speed, cadence, mediolateral trunk acceleration, and mediolateral interstep trunk-acceleration variability for each trial. Participants compensated for sudden reduction of lighting by reducing their walking speed. Compared with performance at equivalent speeds during normal lighting, cadence, trunk acceleration, and interstep trunk-acceleration variability initially increased. All variables showed an asymptotic approximation toward normal values during 60-90 s of walking in subdued lighting. The authors suggest that the sudden transition from normal to marginal lighting, rather than marginal lighting itself, may challenge locomotor control.     

Adaptation in Visuomanual Tracking Depends on Intact Proprioception

The role of arm proprioception in motor learning was investigated in experiments in which, by moving the arm, subjects followed the motion of a target displayed on a monitor screen. Adaptive capabilities were tested in visuomanual tracking tasks following alterations in the relationship between the observer's actual arm movement and visual feedback of the arm movement given by a cursor motion on the screen. Tracking performance and adaptive changes, measured in terms of spatiotemporal error, tracking trajectory curvature, and spatial gain, were compared in 7 control subjects (CSs) and in 1 deafferented subject (DS). CSs adapted appropriately to altered visuomanual relationships; those changes were present in trials immediately after restoration of normal scaling. In contrast, although the DS modified his tracking strategy from trial to trial according to the altered conditions, he did not show plastic changes in internal visuomanual scaling. Like the results of prismatic adaptation experiments, the present results suggest that arm proprioception contributes to the plastic changes that follow alterations in the scaling of visuomanual gain.     

Effects of Pointing Rate and Availability of Visual Feedback on Visual and Proprioceptive Components of Prism Adaptation

The withdrawal of vision of the arm during a manual aiming task has been found to result in a large increase in aiming error, regardless of the amount of practice in normal vision before its withdrawal. In the present study, the authors investigated whether the increase in error reflects the domination of visual afferent information over the movement representation developed during practice to the detriment of other sources of afferent information or whether it reflects only transformation errors of the location of the target from an allocentric to an egocentric frame of reference. Participants (N = 40) performed aiming movements with their dominant or nondominant arm in a full-vision or target-only condition. The results of the present experiment supported both of those hypotheses. The data indicated that practice does not eliminate the need for visual information for optimizing movement accuracy and that learning is specific to the source or sources of afferent information more likely to ensure optimal accuracy during practice. In addition, the results indicated that movement planning in an allocentric frame of reference might require simultaneous vision of the arm and the target. Finally, practice in a target-only condition, with knowledge of results, was found to improve recoding of the target in an egocentric frame of reference.     

Visuo-Proprioceptive Matching Errors Are Consistent with Biases in Distance Judgments

People make systematic errors when matching the location of an unseen index finger with that of a visual target. These errors are consistent over time, but idiosyncratic and surprisingly task-specific. The errors that are made when moving the unseen index finger to a visual target are not consistent with the errors when moving a visual target to the unseen index finger. To test whether such inconsistencies arise because a large part of the matching errors originate during movement execution, we compared errors in moving the unseen finger to a target with biases in deciding which of two visual targets was closer to the index finger before the movement. We found that the judgment as to which is the closest target was consistent with the matching errors. This means that inconsistencies in visuo-proprioceptive matching errors are not caused by systematic errors in movement execution, but are likely to be related to biases in sensory transformations.     

Effects of Pointing Rate and Availability of Visual Feedback on Visual and Proprioceptive Components of Prism Adaptation

While looking through laterally displacing prisms, subjects pointed 60 times straight ahead of their nose at a rate of one complete movement every 2 or 3 s, with visual feedback available early in the pointing movement or delayed until the end of the movement. Sagittal pointing was paced such that movement speed covaried with pointing rate. Aftereffect measures (obtained after every 10 pointing trials) showed that when the limb became visible early in a pointing movement, proprioceptive adaptation was greater than visual, but when visual feedback was delayed until the end of the movement, the reverse was true. This effect occurred only with the 3-s pointing rate, however. With the 2-s pointing rate, adaptation was predominately proprioceptive in nature, regardless of feedback availability. Independent of the availability of visual feedback, visual adaptation developed more quickly with 3-s pointing, whereas proprioceptive adaptation developed more rapidly with 2-s pointing. These results are discussed in terms of a model of perceptual-motor organization in which the direction of coordinative (guidance) linkage between eye-head (visual) and hand-head (proprioceptive) systems (and consequently the locus of discordance registration and adaptive recalibration) is determined jointly by pointing rate and feedback availability. An additional effect of pointing rate is to determine the rate of discordant inputs. Maximal adaptive recalibration occurs when the input (pointing) rate matches the time constant of the adaptive encoder in the guided system.     

视觉适应及其神经机制

视适应使得视觉系统可以连续地根据外界环境的变化做出调整, 改善了对世界的感知。研究提示, 适应影响了对许多基本的视觉属性的加工, 诸如亮度、对比度、运动、颜色等, 也包括对复杂的刺激如面孔等。视适应发生于视觉加工流的多个阶段, 从视网膜到初级视觉皮层以及之后的脑区(例如纹外皮层, 梭状回面孔区)。关于视适应的机制解释, 已从早期的神经元反应疲劳解释发展成当今更流行的标准化模型理论等。最近的适应研究证明, 视觉适应由时间尺度上快慢不同的多重机制控制, 这被认为赋予了视觉系统有效应对环境中不同时间尺度的变化的能力。     

橡胶手错觉:拥有感研究的实验范式及其应用

橡胶手错觉是一种健康个体将非肉体的假手视为自己真实身体的一部分的体验, 这种错觉可以通过同时轻刷被试面前可见的橡胶手及其不可见的真手而产生.橡胶手错觉已成为一种研究身体拥有感的重要范式, 其产生机制可以分为“自下而上的认知匹配”与“自上而下的认知匹配”两种加工方式.前者涉及视觉与触觉刺激的同步性; 而后者涉及被试心中预存的身体意象与身体图式(包括真假手之间模态特征,位置空间的相似性).综合上述证据, 身体模型假说与个人边缘空间理论进一步为拥有感产生的复杂机制提供了整合两种加工方式的解释.橡胶手错觉范式已经被用于探索精神分裂症患者等特殊被试病理分析,错觉产生和心理特质之间的关系, 以及神经外科和术后恢复上.未来的研究应该更加重视范式本身的拓展, 应用虚拟现实技术来提高身体模态的仿真效果, 利用橡胶手拥有感的易感性作为筛选与预测身体意象障碍疾病的指标.     

Virtual reality and the new psychophysics

Virtual reality (VR) promises methodological rigour with the extra benefit of allowing us to study the context-dependent behaviour of individuals in their natural environment. Pan and Hamilton (2018, Br. J. Psychol.) provide a useful overview of methodological recommendations for using VR. Here, we highlight some other aspects of the use of VR. Our first argument is that VR can be useful by virtue of its differences from the normal perceptual environment. That is, by virtue of its relative non-realism and poverty of its perceptual elements, it can actually offer increased clarity with respect to the features of interest for the researcher. Our second argument is that VR exerts its measurable influence more by eliciting an acceptance of the virtual world (i.e., ‘suspension of disbelief’) rather than by eliciting a true belief of the realism of the VR environment. We conclude by providing a novel suggestion for combining neuroimaging methods with embodied VR that relies on the suspension of disbelief.     

虚拟学习环境下图形加工的认知负荷研究

基于单探测变化觉察和双任务范式,采用项目数量（3）×呈现时间（2）×文字线索（2）混合实验设计,对沉浸式虚拟学习环境图形加工特征和认知负荷进行探讨,以任务绩效法与主观测量法评定认知负荷。44名大学生的实验结果显示：（1）项目数量对虚拟空间图形识记主任务绩效和主观认知负荷有显著影响,项目数量越多,主任务正确率越低,反应时越长,主观评定认知负荷越高,同时加工刺激数量以4个为宜;（2）呈现时间对虚拟空间图形识记次任务绩效有显著影响,呈现时间越长,次任务正确率越高,呈现时间超过0.5s有利于次任务加工;（3）文字线索对虚拟图形识记认知负荷有显著影响,重复性文字线索会增加认知负荷。结果表明,在沉浸式虚拟环境中,图形加工的认知负荷特点与平面和三维图形基本一致,项目数量多、呈现时间短以及有重复性文字线索时,认知负荷更高;任务绩效和主观测量评定指标在反映认知负荷强度上不完全一致。     

Adaptation to a Nonlinear Visuomotor Amplitude Transformation With Continuous and Terminal Visual Feedback

The control of a cursor on a computer monitor offers a simple means of exploring the limits of the plasticity of human visuomotor coordination. The authors explored the boundary conditions for adaptation to nonlinear visuomotor amplitude transformations. The authors hypothesized that only with terminal visual feedback during practice, but not with continuous visual feedback, humans might develop an internal model of the nonlinear visuomotor amplitude transformation. Thus, 2 groups were engaged in a sensorimotor adaptation task receiving either continuous or terminal visual feedback during the practice phase. In contrast to expectations, adaptive shifts and aftereffects observed in visual open-loop tests were linearly related to target amplitudes for both groups. Although the 2 feedback groups did not differ with respect to adaptive shifts and aftereffects, terminal visual feedback resulted in stable visual open-loop performance for an extended period, whereas movement errors increased after continuous visual feedback during practice. The benefit of continuous visual feedback, on the other hand, was faster closed-loop performance, indicating an optimization of visual closed-loop control.     

Teaching and Learning Logic in a Virtual Learning Environment

Teaching and learning in a virtual learning environment (VLE)poses some difficulties, but also challenges and opportunitiesto rethink the whole learning process, particularly in abstractsubjects like logic or high level mathematics. On the otherhand, resources and ways to work, now available in VLEs, mightsoon extend to all kinds of environments. In this paper, wewill present experiences at the Open University of Catalonia(UOC), a particular VLE, concerning the whole process of teachinglogic and mathematics. In addition, we will discuss some challengesand we will present some innovation projects allowed by thepresent and near future technologies.     

Sense of reality,reality testing and reality processing in borderline patients1

Although borderline patients are suitable for it, they often undergo repeated testing of phantasies against objective reality without success. A reason for these partial failures is that subjects have not been able to build a solid sense of reality and have found many diffi culties for processing reality demands and possibilities. The author puts forward some thoughts on this question, such as the importance of working through the depressive position and the Oedipus complex in the process of building up a solid sense of reality. A sense of reality also favours continuous reality processing. When reality processing becomes as continuous as life itself, the repetition of individual reality tests becomes less frequent and necessary, and more satisfying. The author also presents some recommendations for the psychoanalytic treatment of such patients, stressing the importance and the diffi culties of the introduction of the borderline patient into the triangular situation because primitive defences‐such as disavowal and denial‐are mobilized.     

虚拟现实技术在心理学领域的应用与展望

虚拟现实(VR)技术因其能够提高实验研究的生态效度、条件控制水平、可重复性以及避免实地操作带来的危险,被众多研究者引入心理学领域。VR技术除了被用于改良实验程序外,也广泛应用于注意、记忆和执行能力等神经心理测验评估,在恐惧症、焦虑症、创伤后应激障碍和精神分裂症等精神障碍的临床治疗中亦取得丰硕成果。未来研究可致力于改进VR技术本身存在的问题、扩大样本量并扩展研究方法和范围,为VR应用提供更可靠的信效度证据。     

Virtual reality: A new track in psychological research

One major challenge of social interaction research is to achieve high experimental control over social interactions to allow for rigorous scientific reasoning. Virtual reality (VR) promises this level of control. Pan and Hamilton guide us with a detailed review on existing and future possibilities and challenges of using VR for social interaction research. Here, we extend the discussion to methodological and practical implications when using VR.