Contribution of binocular vision to the performance of complex manipulation tasks in 5–13 years old visually-normal children

Individual studies have shown that visuomotor coordination and aspects of binocular vision, such as stereoacuity and dynamic vergence control, continue to improve in normally developing children between birth and early teenage years. However, no study has systematically addressed the relationship between the development of binocular vision and fine manipulation skills. Thus, the aim of this cross-sectional study was to characterize performance of complex manipulation tasks during binocular and monocular viewing. Fifty-two children, between 5 and 13 years old, performed 2 manipulation tasks: peg-board and bead-threading under randomized viewing conditions. Results showed that binocular viewing was associated with a significantly greater improvement in performance on the bead-threading task in comparison to the peg-board task and the youngest children showed the greatest decrement in task performance under the monocular viewing condition when performing the bead-threading task. Thus, the role of binocular vision in performance of fine manipulation skills is both task- and age-dependent. These findings have implications for assessment of visuomotor skills in children with abnormal binocular vision, which occurs in 2–3% of otherwise typically developing children.     

Higher order balance control: Distinct effects between cognitive task and manual steadiness constraint on automatic postural responses

In the present experiment, we aimed to evaluate the interactive effect of performing a cognitive task simultaneously with a manual task requiring either high or low steadiness on APRs. Young volunteers performed the task of recovering upright balance following a mechanical perturbation provoked by unanticipatedly releasing a load pulling the participant’s body backwards. The postural task was performed while holding a cylinder steadily on a tray. One group performed that task under high (cylinder’ round side down) and another one under low (cylinder’ flat side down) manual steadiness constraint. Those tasks were evaluated in the conditions of performing concurrently a cognitive numeric subtraction task and under no cognitive task. Analysis showed that performance of the cognitive task led to increased body and tray displacement, associated with higher displacement at the hip and upper trunk, and lower magnitude of activation of the GM muscle in response to the perturbation. Conversely, high manual steadiness constraint led to reduced tray velocity in association with lower values of trunk displacement, and decreased rotation amplitude at the ankle and hip joints. We found no interactions between the effects of the cognitive and manual tasks on APRs, suggesting that they were processed in parallel in the generation of responses for balance recovery. Modulation of postural responses from the manual and cognitive tasks indicates participation of higher order neural structures in the generation of APRs, with postural responses being affected by multiple mental processes occurring in parallel.     

Trait predictors of placebo responses in itch

This study investigated trait predictors of placebo responses in the context of inflammatory skin reactions. This was a randomized, cross-over, experimental study using a deceptive placebo protocol. A healthy sample of volunteers (N = 48) completed online personality measures, then attended two laboratory sessions in which short-term inflammatory skin reactions were induced. One was a control session and the other the ‘treatment’ session in which a placebo cream was administered with the suggestion of a reduced skin reaction. A placebo response was defined as smaller skin reactions in control vs. treatment sessions. The traits ego resiliency and neuroticism were selected as possible predictors of placebo responses. Traits were selected in consideration of the two-faceted transactional model of placebo responsiveness and in light of empirical and psychometric considerations ego resiliency emerged as a consistent predictor of placebo responses in itch (p < .05). This is the first study to identify trait predictors of placebo responses in inflammatory skin reactions. Ego resiliency may typify greater placebo responsiveness; however, this may only be in certain contexts. Matching treatment approaches to bio-behavioural response tendencies may be useful clinically if the placebo component of traditional treatments can be enhanced.     

运动区Beta节律的活动特点及功能意义

人类大脑运动皮质的Beta(15~30 Hz)和Mu节律(8~14 Hz)有共同的活动特征,研究指出二者可能是联合的脑电成分。然而越来越多研究表明运动区Beta节律可能独立于Mu节律,且具有特殊的功能意义。线索诱发的Beta节律降低、运动前Beta节律降低和运动后Beta节律回复增强都是Beta与Mu节律不同的活动形式,表明运动区Beta节律有其独特的心理意义。本文主要对运动区Beta节律不同于Mu节律的活动特征及已有的理论解释进行了梳理和分析,并结合儿童研究的数据,从发展的角度对运动后Beta节律的理论假说进行了评述,最后在此基础上为进一步探索运动区Beta节律的功能意义提出了研究的展望。     

Selective impairment of sensorimotor representations following short-term upper-limb immobilization

In the present experiment, we examined whether short-term upper-limb immobilization would selectively affect the representation of the immobilized limb (using a hand laterality task) or whether the effect of immobilization would extend to another body part (using a foot laterality task). A rigid splint placed on the participants’ left hand was used for immobilization. A control group did not undergo the immobilization procedure. We compared the participants’ performances on the hand and foot laterality tasks before (T₁) and after (T₂) a 48-hour delay, corresponding to the immobilization period. For controls, response time analysis indicated a benefit of task repetition for the recognition of both hand and foot images. For the immobilized group, a slowdown of performance appeared in T₂ for hand images, but not for foot images. The reduced benefit of task repetition following left-hand immobilization appeared for both the immobilized and non-immobilized hand images. These findings revealed that the general cognitive representation of upper-limb movements is affected by the decrease in input/output signal processing due to the left-hand immobilization, while the cognitive representation of lower-limb movements is not.     

Effects of acute administration of nicotine and lobeline on agonistic encounters in male mice

The effects of acute administration of two nicotinic ligands, (‐)‐nicotine and (‐)‐lobeline were examined on isolation‐induced aggression in mice. Individually housed male mice confronted anosmic “standard opponents” in a neutral arena 10 min after drug administration. Encounters were videotaped and evaluated using an ethologically based analysis facilitating estimation of time allocated to 11 broad behavioral categories. Nicotine did not have significant effects on threat or attack but significantly diminished time allocated to digging. The lowest dose of lobeline significantly diminished attack and induced a slight increase of immobility without significantly diminishing other behaviors with motor components. The intermediate and highest dose of lobeline reduced time allocated to all behaviors with motor components. It is concluded that these two nicotinic agonists produce different behavioral profiles during agonistic encounters in mice but that this test may not facilitate assessing the impact of such drugs on irritability. Aggr. Behav. 26:376–385, 2000. © 2000 Wiley‐Liss, Inc.     

Tablet Use in Young Children is Associated with Advanced Fine Motor Skills

Abstract

To evaluate whether frequent interactive tablet-use at preschool age is associated with improved fine motor skills and to describe tablet-use in young children. Cross-sectional study with 78 children, aged 24–42?months: group 1 with previous frequent tablet-use exposure (n?=?26), group 2 without previous tablet-use exposure (n?=?52). Fine motor skills were evaluated with the Bayley-III. Socioeconomic data and home environment quality were similar in both groups. Fine motor skills of group 1 were better than those of group 2 (p?=?0.013). Most participating children carried out passive and active tablet activities, usually accompanied by parents, not exceeding time recommendations for young age. We observed a difference in fine motor skills in young children slightly favoring those with tablet-use experience.     

The Influence of Contraction Types on the Relationship Between the Intended Force and the Actual Force

Abstract

It has been demonstrated that the intended force (subjective estimation of force) does not always match to actual force without external feedback. The purpose of this study was to compare the influence of ballistic and tonic contractions on the relationship between the intended and actual force. Subjects produced isometric force at requested percentages of their MVC (20, 40, 60 and 80%) based on subjective estimation of force under two conditions (tonic and ballistic conditions). The tonic condition was to maintain force production, whereas the ballistic condition was to produce force as fast as possible. As a result, the actual force amplitude, the coefficient of variance and EMG amplitude were larger under the ballistic contraction compared with the tonic condition, even the same intended force levels. These results suggest that different motor unit activity and control systems in the ballistic and tonic contractions could alter the relationship between the intended force and the actual force.     

隐性知识的具身机制、转化与管理

隐性知识是知识经济时代的发展关键,在多个学科的知识体系中占有重要位置。由于隐性知识有内隐表征、主观经验和情境性等多种跨层属性,导致管理学、体育学等学科面临隐性知识转化与管理的难题。隐性知识本质上是具身性的,身体经验与情境的互动为个体在知识系统中归纳与形成隐性知识提供了基础。隐性知识的提取与应用机制为组织对隐性知识的转化与管理提供了桥梁,而隐性知识的具身机制是其提取与应用的依据。本文将基于具身认知理论,结合多个学科的研究证据,对不同情境下的隐性知识提取与应用机制进行分析,旨在梳理出隐性知识的具身机制,并针对隐性知识的未来研究、转化与管理提出建议。     

左侧背外侧前额叶在程序性运动学习中的作用

程序性运动学习包括序列学习和随机学习。神经影像学研究表明背外侧前额叶皮层(DLPFC)和初级运动皮层(M1)在程序性运动学习中发挥重要作用, 但DLPFC和M1之间的联通性及其与不同程序性运动学习的关系尚不明确。本研究采用连续反应时间任务, 结合经颅磁刺激(TMS)方法, 探讨左侧DLPFC到M1的联通性在不同程序性运动学习中的差异。实验1采用两连发TMS探测DLPFC到M1的最佳投射时间点; 实验2, 被试分为2组, 分别进行序列学习和随机学习, 在学习前、后采集行为学数据, 以及M1的运动诱发电位和DLPFC-M1联通性的电生理学数据。行为学结果发现序列学习组的学习效果更佳; 电生理学结果发现, 两组被试学习前、后M1的运动诱发电位均未发生改变; 在最佳时间投射点、适当刺激强度下, 序列学习组DLPFC-M1联通性发生改变, 且与学习成绩相关, 而随机学习组没有改变。结果说明DLPFC到M1的联通性增强可能是序列学习成绩更佳的重要原因, 这一结果从电生理角度为DLPFC在运动学习中的作用提供了重要证据。