It's the journey,not the destination: Locomotor exploration in infants

What incites infant locomotion? Recent research suggests that locomotor exploration is not primarily directed toward distant people, places, or things. However, this question has not been addressed experimentally. In the current study, we asked whether a room filled with toys designed to encourage locomotion (stroller, ball, etc.) elicits different quantities or patterns of exploration than a room with no toys. Caregivers were present but did not interact with infants. Although most walking bouts in the toy‐filled room involved toys, to our surprise, 15‐month‐olds in both rooms produced the same quantity of locomotion. This finding suggests that mere space to move is sufficient to elicit locomotion. However, infants' patterns of locomotor exploration differed: Infants in the toy‐filled room spent a smaller percent of the session within arms' reach of their caregiver and explored more locations in the room. Real‐time analyses show that infants in the toy‐filled room took an increasing number of steps per bout and covered more area as the session continued, whereas infants in the no‐toy room took fewer and fewer steps per bout and traveled repeatedly over the same ground. Although not required to elicit locomotion, moving with toys encouraged infants to travel farther from their caregivers and to explore new areas.     

Effect of Nonspecific Chronic Low Back Pain on Walking Economy: An Observational Study

The authors investigated the effects of chronic low back pain (LBP) and walking speed (WS) on metabolic power and cost of transport (CT). Subjects with chronic nonspecific LBP (LBP group [LG]; n = 9) and healthy (control group [CG]; n = 9) were included. The test battery was divided into 3 blocks according to WS as follows: preferred self-selected speed (PS), and lower and higher than the PS. In each block, the volunteers walked 5 min, during which oxygen consumption was measured. Although without differences between groups, the LG had CT lower in slower speeds than in faster speeds. Walking speed affected CT only in the LG, which the group had the greatest walking economy at slower speeds.     

When Walking Makes Perception Better

ABSTRACT— When we move, the visual world moves toward us. That is, self-motion normally produces visual signals (flow) that tell us about our own motion. But these signals are distorted by our motion: Visual flow actually appears slower while we are moving than it does when we are stationary and our surroundings move past us. Although for many years these kinds of distortions have been interpreted as a suppression of flow to promote the perception of a stable world, current research has shown that these shifts in perceived visual speed may have an important function in measuring our own self-motion. Specifically, by slowing down the apparent rate of visual flow during self-motion, our visual system is able to perceive differences between actual and expected flow more precisely. This is useful in the control of action.     

Walking in an environment of moving ground texture

The visual control of global body movements has mainly been studied in terms of the maintenance of balance. The present experiment examined the effect of moving visual surroundings on the speed of locomotion. A virtually boundless optical environment was generated by the projection of a dotted texture on the ground that was reflected on large vertical mirrors fixed along the walls of the room. Subjects' head velocity was recorded over a walking path of about 10 m along the projection surface. In the experimental sessions, the texture was animated and moved at different speeds in the same direction as the subject or in the opposite direction. In the control condition, the projected texture remained motionless and therefore appeared to pass by at the subjects' walking speed. The subjects' task was to maintain a constant walking speed as far as possible over the different conditions. Changes in walking speed give indications of how the processing of optical flow modulates locomotor activity.     

Leg Asymmetries and Coordination Dynamics in Walking

Models of interlimb coordination (H. Haken, J. A. S. Kelso, &; H. Bunz, 1985 Haken, H., Kelso, J. A. S. and Bunz, H. 1985. A theoretical model of phase transitions in human hand movements. Biological Cybernetics, 51: 347–356. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; P. N. Kugler &; M. T. Turvey, 1987 Kugler, P. N. and Turvey, M. T. 1987. Information, natural law, and the self-assembly of rhythmic movement, Hillsdale, NJ: Erlbaum.  [Google Scholar]) were tested in walking by examining the role of asymmetries between limbs. Participants walked on a treadmill with and without a metronome. Five asymmetry conditions were created via ankle loads of 0, 3, or 6 kg on either leg. With the metronome, participants matched the target period. Without the metronome, stride rate slowed as the mass was increased on either leg. The loads led to an increase in stride period that was predicted by Huygens’ law and the hybrid pendulum-spring model. In agreement with extended Haken–Kelso–Bunz model predictions, leg asymmetries led to deviations from antiphase coordination. Also, perception–action coordination was influenced by the asymmetry between the legs and metronome. In contrast, no predicted stability effects were observed. These findings reveal that some properties of interlimb coordination, apparent in laboratory-based tasks, can also be observed in human walking.     

Distraction Affects the Performance of Obstacle Avoidance During Walking

In this study, dual-task interference in obstacle-avoidance tasks during human walking was examined. Ten healthy young adults participated in the experiment. While they were walking on a treadmill, an obstacle suddenly fell on the treadmill in front of their left leg during either midswing, early stance, or late stance of the ipsilateral leg. Participants were instructed to avoid the obstacle, both as a single task and while they were concurrently performing a cognitive secondary task (dual task). Rates of failure, avoidance strategy, and a number of kinematic parameters were studied under both task conditions. When only a short response time was available, rates of failure on the avoidance task were larger during the dual task than during the single task. Smaller crossing swing velocities were found during the dual task as compared with those observed in the single task. The difference in crossing swing velocities was attributable to increased stiffness of the crossing swing limb. The results of the present study indicated that divided attention affects young and healthy individuals' obstacle-avoidance performance during walking.     

脂多糖免疫激活导致抑郁性行为的动物研究：剂量和时程效应

“抑郁症细胞因子假说”的提出为抑郁障碍的病因学研究提供了一个新的方向,为了探讨脂多糖（lipopolyaccharide,LPS）诱导的免疫激活与抑郁性行为产生之间的关系,本研究采用50只SD大鼠随机分为五组LPS400,LPS200,LPS50,LPS10,LPS0,分别于实验期第0天和第3天注入LPS400ug/kg,,200ug/kg,50ug/kg,10ug/kg和生理盐水。以糖精水偏爱,旷场行为和高架十字迷宫评定大鼠LPS注射后2小时,24小时,48小时的行为变化。结果显示一次LPS注射后2小时,LPS50,LPS200,LPS400组动物与生理盐水组动物相比较,其糖精水偏爱分数（p<0.01）,旷场中的水平活动距离(p<0.01)和直立行为(p<0.01)以及高架十字迷宫中的闭合臂进入次数(p<0.01)和开放臂进入次数显著下降(p<0.01);重复注射后2小时LPS注射组动物的闭合臂进入次数显著降低（p<0.01）;但LPS10组与生理盐水组动物在行为上没有差异,50ug/kg,200ug/kg和400ug/kg剂量的各组之间没有差异。LPS注射后24小时和48小时以及重复注射后大鼠的行为没有发现显著变化。提示LPS诱导的免疫激活对抑郁行为产生有一定的作用。免疫激活的细胞因子能够导致动物出现明显的抑郁性行为,但是这种行为缺乏长时程效应,因此LPS诱导的抑郁障碍的动物模型应用是非常有限的。免疫激活的前炎性细胞因子可能是导致抑郁障碍产生的其中一个原因而不是唯一原因。     

Iterative Spatial Updating During Forward Linear Walking Revealed Using a Continuous Pointing Task

Abstract

The continuous pointing task uses target-directed pointing responses to determine how perceived distance traveled is estimated during forward linear walking movements. To more precisely examine the regulation of this online process, the current study measured upper extremity joint angles and step-cycle kinematics in full vision and no-vision continuous pointing movements. Results show perceptual under-estimation of traveled distance in no-vision trials compared to full vision trials. Additionally, parsing of the shoulder plane of elevation trajectories revealed discontinuities that reflected this perceptual under-estimation and that were most frequently coupled with the early portion of the right foot swing phase of the step-cycle. This suggests that spatial updating may be composed of discrete iterations that are associated with gait parameters.     

Postural and Locomotor Contributions to Affordance Perception

The authors sought to evaluate the relative importance of locomotor control and postural control in the perception of affordances. While seated in a stationary wheelchair, participants made a series of judgments about the minimum lintel height under which they could roll in the wheelchair. Prior to making judgments, participants were given brief (～2 min) experience with wheelchair locomotion. They expected that this practice would influence the accuracy of subsequent affordance judgments. During practice, participants moved under their own power (using their hands on the wheels) or with an experimenter pushing the wheelchair. Also during wheelchair locomotion the participant's head was restrained, or was not. Results revealed that head restraint during the practice session had no effect on the accuracy of subsequent judgments. By contrast, the judgments of participants who controlled locomotion during practice were significantly more accurate than the judgments of participants who had not controlled their locomotion during practice.     

早中期青少年未来规划的发展及其与父母教养行为的关系：行为自主的中介效应*

采用追踪设计,以948名初中和高中学生为被试,在考察早中期青少年对教育和职业领域的未来规划发展特点的基础上,探讨了父母教养行为对青少年未来规划的预测作用以及青少年行为自主在其中的中介效应。结果表明：(1)在两次测量中,中期青少年的教育探索水平增长,早期青少年的教育探索变化不显著;早期青少年的职业探索和投入水平均高于中期青少年。(2)父母的接纳/参与能正向预测青少年当时及以后对教育和职业的探索和投入;父母的严厉/监督仅能正向预测青少年当时的教育探索和投入。(3)行为自主在父母的接纳/参与对青少年未来规划的预测中起部分中介效应。     

调节模式理论：自我调节领域的新进展

作为Higgins自我调节理论体系的重要组成部分,调节模式理论认为自我调节包括运动和评估两种模式,两者分别关注状态的改变和最佳方案的获得。本文分析了两种调节模式的特点并介绍了其测量及诱导方法,概括了调节模式对基本心理现象的影响以及调节匹配效应有关的研究,并对新近进展进行了介绍。未来研究尚可针对调节模式的形成、多元化测量工具及诱发范式的开发、及其对反事实思维等特定心理现象的影响等问题作更深入探讨。     

Walking and periventricular leukomalacia: locomotor characteristics and brain imaging (MRI)

The aim of the present study was to compare the walking abilities in infants with and without periventricular leukomalacia and to see whether the severity of the brain damage was related to locomotor outcome of the infants at 12 and 18 months. 47 newborns were included in the study based on white matter abnormalities on ultrasound. Magnetic resonance imaging (MRI) recordings during the neonatal period were used to identify and quantify the location and severity of the brain lesions. Locomotor outcome was assessed in terms of disability at 12 and 18 months. The quality of walking, including global and segmental gait parameters, was measured for the infants who could walk independently at 18 months and compared to a group of healthy control infants. The number of children who could walk was related to the extent of white matter abnormalities seen on the neonatal MRI, but the quality of walking was not.     

McGraw and the Development of Unaided Walking

McGraw's research and theoretical principles concerning early neuromotor development are reexamined in light of contemporary research—primarily for unaided walking. McGraw studied emergence of higher order control of neuromotor behavior with special emphasis on development from the neonate's reflexive repertoire to the onset of purposive behavior toward the end of the first year. Contemporary research supports and clarifies her observations providing greater detail about the factors involved in the formation of higher order control and amplifying the role of experience, particularly for decreasing disorganization during periods of transition. The development from reflexive to instrumental control is clarified as an alternative to the disorganized phase and to the “disappearance” of “reflexive” behaviors. A cognitive metamorphosis at the end of the first year not only explains the onset of qualitatively new behaviors, including purposive neuromotor actions, but provides the infant with characteristics that define our species: unaided walking, functional object use, and naming. Possible mechanisms underlying this transition are discussed in terms of the emergence of a higher level of consciousness.     

The Maternal (Non) Responsiveness Questionnaire: Initial Factor Structure and Validation

The purpose of this paper was to examine the reliability, stability, and convergent and predictive validity of the newly developed Maternal Responsiveness Questionnaire (MRQ). Participants were 224 first‐time mothers. Mothers completed the MRQ when their infants were 6 and 14 months old. Convergent validity was examined in relation to mother‐reported personality, depressive symptoms, and emotion socialization practices and observed maternal sensitivity. Predictive validity was examined in relation to mother‐reported child behaviour problems and social competence, infant attachment security assessed via the Strange Situation, and observed child dysregulation. Three MRQ factors emerged based on exploratory factor analysis and were confirmed via confirmatory factor analysis: responsiveness, non‐responsiveness, and delayed responsiveness. All three scales demonstrated good internal consistency reliability and significant stability from 6 months to 14 months. Consistent evidence emerged for convergent and predictive validity of the non‐responsiveness subscale, but not the other subscales. The potential utility of the non‐responsiveness subscale of the MRQ is discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

The Development of Infants' Spatial Categories

ABSTRACT— Early theories of how infants develop spatial concepts focused on the perceptual and cognitive abilities that contribute to this ability. More recent research, however, has centered on whether experience with spatial language might also play a role. The present article reviews how infants learn to form spatial categories, outlining the perceptual and cognitive abilities that drive this learning, and examines the role played by spatial language. I argue that infants' spatial concepts initially are the result of nonlinguistic perceptual and cognitive abilities, but that, as infants build a spatial lexicon, spatial language becomes an important tool in the spatial categories infants learn to form.     

Towards a broader scope of biomechanics in developmental studies: a commentary on Jensen (2005)

In this article, we discuss where biomechanical analysis can contribute to our understanding of motor development, and more particularly in what ways biomechanics can contribute to (1) explaining the universal sequence in motor milestones; (2) explaining variations in developmental sequence between individuals; (3) understanding the impact of context on the actions of an individual; and (4) understanding, preventing, and managing chronic disabilities. In our view, biomechanics is concerned with the dynamics of the musculo‐skeletal system (MSS) and thus provides insights in the way motion is affected by the activation of muscles and the mechanical interaction between the MSS and the environment. Biomechanical analysis is important in understanding the development of actions that depend on the perceptual‐motor loop although it cannot provide a full account of the changes in the behaviour. The contributions and limitations of specific biomechanical analyses such as the inverse and forward dynamical models are discussed in the light of the article of Jensen (2005). Copyright © 2005 John Wiley & Sons, Ltd.     

Development and Psychometric Evaluation of the Social Justice Scale (SJS)

The study describes the development of the Social Justice Scale (SJS). Practitioners, educators, students, and other members of the community differ on their attitudes and values regarding social justice. It is important to assess, not only individuals' attitudes and values around social values, but also other constructs that might be related to social justice behaviors. The implication of Ajzen in Organizational Behavior and Human Decision Processes 50:179-211, (1991) theory of planned behavior suggests that attitudes, perceived behavioral control, and social norms predict intentions, which then lead to behaviors. A scale was designed to measure social justice-related values, attitudes, perceived behavioral control, subjective norms, and intentions based on a four-factor conception of Ajzen's theory. Confirmatory factor analysis and analyses for reliability and validity were used to test the properties of the scale.     

Unweighting infants reveals hidden motor skills

We investigated the role of rate limiting factors in development using walking as a model system. The achievement of bipedal posture and locomotion are among the most significant achievements in an infant's first year, with poor balance and weak muscles long proposed as the rate limiting factors. Compensating for either may reveal upright motor skill that has not yet emerged in the infant's natural repertoire. To probe this question, we unweighted prewalking infants and measured their performance in various standing and walking behaviors while unweighted compared to baseline. Our secondary objective was to determine if the influence of unweighting was related to infants’ locomotor experience. Infants stood unsupported for longer durations with 20% or 40% unweighting. Infants took more independent steps and more steps with one hand held with 40% unweighting. No differences in transition to/from standing were observed. Locomotor experience was related to the influence of unweighting during cruising and walking with a push toy. This is the first report of more advanced motor skills—longer periods of unsupported standing and the emergence of independent walking—revealed by unweighting infants. We interpret our observations to suggest that the refinement of motor control needed to support bipedal posture and locomotion precedes the functional emergence of these skills in infants. In other words, the musculoskeletal components required for walking are slower to develop than the neurological factors – and consequently may be the rate limiters. We further suggest that training regimens including unweighting should be explored in infants with motor delays.     

婴儿心理理论的发展:表现和机制

婴儿心理理论发展研究是探索人类社会认知起源、发生和发展的重要领域.从联合注意、情绪理解、意图理解、愿望理解和错误信念理解等方面分析了几个月至3岁左右的婴儿心理理论发生和发展的研究现状.为了探讨3岁以下婴儿心理理论的发展过程,研究者发展了一些适合婴儿语言和行为发展特征的非言语和言语测试任务,包括非言语自发—反应错误信念任务、言语自发—反应错误信念任务,同时也采用眼动技术和事件相关电位技术来考察心理理论发展水平和发展机制.婴儿心理理论的发生和发展在不同测试任务上表现出一定的年龄特征.这与认知功能(如语言、执行功能)的发展、环境因素(如家庭、同伴、文化)以及神经系统发育有关.也有一些最新研究从心理理论发生和发展的基因、激素水平进行了探讨.最后提出了该领域未来研究可以进一步探讨的问题.     

Assessing Stress in Families of Children with ADHD: Preliminary Development of the Disruptive Behavior Stress Inventory (DBSI)

This paper describes the initial development of the Disruptive Behavior Stress Inventory (DBSI). This 40-item measure, which provides indices of the number of stressors experienced during the past 6 months and the rated stressfulness of these events, is designed to assess behavior-related family stress experienced by families of children with attention-deficit/hyperactivity disorder (ADHD). Findings provide strong support for the internal consistency of the DBSI and suggest adequate test-retest reliability. Support for the validity of the measure is suggested by findings that DBSI stress indices differentiate between parents of children with ADHD and those with no history of this disorder. Additional support is provided by findings that scores on the DBSI also differentiate between parents of children with ADHD, combined type and parents of children with ADHD, inattentive type. It is suggested that this measure may provide useful clinical information regarding stress levels in families of children with ADHD and that it may be of potential value as an ADHD treatment outcome measure.