Human Energy Expenditure and Postural Coordination on the Mechanical Horse

The authors investigated and compared the energy expenditure and postural coordination of two groups of healthy subjects on a mechanical horse at 4 increasing oscillation frequencies. Energy expenditure was assessed from the oxygen consumption, respiratory quotient, and heart rate values, and postural coordination was characterized by relative phase computations between subjects (elbow, head, trunk) and horse. The results showed that the postural coordination of the riders was better adapted (i.e., maintenance of in-phase and antiphase) than that of the nonriders, but the energy expenditure remains the same. Likewise, we observed an energy system shifting only for nonriders (from aerobic to lactic anaerobic mode). Finally, cross-correlations showed a link between energy expenditure and postural coordination in the riders (i.e., effectiveness).     

行为遗传学：解决面孔特异性问题争论的新思

面孔刺激的加工存在特异性,但“特异性”的具体内涵仍存在争议。面孔特异性假说认为面孔刺激具有特异性;而专家假说则认为存在特异性的是整体加工的模式。通过对相关领域近年来主要的研究结果的总结,发现争论中混淆了两个概念——加工类型和刺激类型,二者正交分解可将争论归纳为三个假设：1）面孔整体加工特异性的假设;2）面孔刺激特异性的假设;3）专家加工特异性的假设。在未来的研究中,行为遗传学可为解决该争论提供合适的方法     

Postural Mechanisms to Control Body Displacements in the Performance of Lateral Gaze Shifts

Medialateral postural control mechanisms (bodyweight distribution and center of pressure location) have been studied in static conditions. Our objective was to determine how these mechanisms are adjusted to perform voluntary movements, in our case 80° lateral gaze shifts at 0.125 Hz and 0.25 Hz. In healthy, young adults, we expected body marker (neck, lower back) and center of pressure displacements to be significantly greater in gaze shift conditions than in the stationary gaze condition. To explain these changes in center of pressure displacement, the amplitude contribution of both mechanisms was expected to increase significantly. All these results were found accordingly. Unexpectedly, the active contribution of the bodyweight distribution mechanism was negatively related to body marker displacements in the gaze shift conditions (ns in stationary condition). Moreover, changes in the contribution of the mechanisms were statistically weaker in effect size than changes in body displacement. However, the participants were not unstable because they performed the visual tasks as requested. We propose that the strength of medialateral postural control mechanisms may not only be strengthened to control challenging ML stance conditions but also slightly weakened to allow the performance of adequate body motions in ongoing tasks.     

Effects of the Central Executive on Postural Control

The authors focused on individual working memory (WM) capacity and examined its effect on postural control. Participants were 79 young volunteers split into two groups of low- and high WM span, based on scores from the Reading Span Test. The length of unrest was measured in the following conditions: double-leg standing as a single (D-S) task, single-leg standing as a single (S-S) task, double-leg standing as a dual (D-D) task, and single-leg standing as a dual (S-D) task. Regarding inte-group comparisons, total length was prolonged significantly between the low- and the high-span groups but only on the S-D task. The present results revealed that dual-task interference emerged in the low-span group when in a more unstable posture.     

Influence of Experience on Postural Control: Effect of Expertise in Gymnastics

The authors investigated how expertise in motor skills that require fine postural control, such as gymnastics, influences postural regulation. Gymnasts and nongymnasts performed a postural stabilization task after anterior-posterior destabilization while looking at a target in front of them. The authors recorded and analyzed the center of pressure and the ankle, knee, and hip displacements. Gymnasts were able to react rapidly after destabilization to decrease their center of pressure and the angular movements. Moreover, they used their knees to stabilize posture, whereas the nongymnasts used their hips. These findings suggest that specific postural experience modifies the ability to coordinate and regulate posture. The authors discuss these results from an ecological perspective.     

Development of Multiple Movement Representations With Practice: Specificity Versus Flexibility

The question addressed in the present experiment was whether an individual who practices a task under different conditions of afferent information develops different movement representations, each of which is based on the most accurate source of afferent information for movement control. In Experiment 1, participants (N = 23) performed a manual aiming movement in a target-only condition for 520 trials before performing in a normal vision condition for an equivalent amount of practice. Control groups performed all practice trials in either a normal vision or a target-only condition. The results revealed that the movement representation developed in the initial (target-only) practice phase remained accessible for movement planning and control. The results of Experiment 2 indicated, however, that participants did not maintain such a representation when their initial practice in the target-only condition was reduced (40 or 160 trials) before they had extensive practice in normal vision. Those results indicate that extensive practice in a target-only and then in a normal vision condition enables an individual to plan and control his or her movement on the basis of the most efficient source of available afferent information. Because visual afferent information provides optimal information for ensuring movement accuracy, however, if initial practice in the target-only condition is only modest or moderate it is likely that that information source will progressively dominate all other sources of afferent information for movement planning and control.     

Postural Control Complexity and Fatigue in Minimally Affected Individuals with Multiple Sclerosis

This study investigated changes in postural control complexity in people with multiple sclerosis (PwMS) before and after a fatigue protocol. Thirteen minimally affected PwMS (1.53 ± 1.03- Expanded Disability Status Scale) and 12 non-MS controls. Postural test included quiet stance on a force platform under two visual conditions (saccades and fixation) before and after a fatigue protocol. Postural complexity was assessed through the multiscale entropy. A three-way ANOVA showed a main effect of fatigue in the medial-lateral direction (p <0.007), with fatigue protocol reducing postural complexity in both groups. No differences were found between groups or visual conditions. Minimally affected PwMS demonstrated similar postural complexity compared with non-MS controls under both visual tasks and showed similar decrements in postural complexity as a result of fatigue.     

Effects of A Dual-Task Intervention in Postural Control and Cognitive Performance in Adolescents

Abstract

The aim was to assess dual- versus single-task training for motor performance and cognitive performance in adolescents. Two experiments were performed. In the first, 30 adolescents were randomized to three groups to determine the effect of dual-task difficulty on postural control: α-scaling and root mean square (RMS). In the second, 20 adolescents were randomized to two groups to determine the effect of dual-task practice to improve working memory. RMS in the post-test was lower than the pre-test in both dual-task groups, while α-scaling was lower in post-test than pre-test only in the high-difficulty dual-task group. A practice effect was observed on the percentage of correct answers only in the dual-task group (p?=?0.035). Thus, dual-task training could enhance motor and cognitive performance more than single-task training.     

Interaction Between the Development of Postural Control and the Executive Function of Attention

The authors examined the interaction between the development of postural control and the development of the executive function of attention in 13 children and 6 adults in dual-task conditions. Participants performed an attentionally demanding cognitive task and a postural task simultaneously. The authors equalized the attentional load of the cognitive task across age groups. Comparative changes in the center of pressure in dual- and single-task conditions indicated that dual tasks interfered with postural performance in the wide stance (WS) and the modified Romberg stance (RS). Children at 4-6 years of age (but not children at ages 7-12 years of age or adults) experienced postural control interference in both stance positions, but interference was greater in the RS (p = .018). For all participants, cognitive task performance in RS was unchanged from that in WS. The knowledge gained from the results of this study will contribute to the design and implementation of academic and preacademic programming for young children. Their performance of an intentionally demanding cognitive task would be enhanced by the provision of appropriately sized desks and chairs or their use of an alternate, less demanding position.     

Effect of Concurrent Visual Feedback Frequency on Postural Control Learning in Adolescents

The purpose was to find better augmented visual feedback frequency (100% or 67%) for learning a balance task in adolescents. Thirty subjects were divided randomly into a control group, and 100% and 67% feedback groups. The three groups performed pretest (3 trials), practice (12 trials), posttest (3 trials) and retention (3 trials, 24 hours later). The reduced feedback group showed lower RMS in the posttest than in the pretest (p = 0.04). The control and reduced feedback groups showed significant lower median frequency in the posttest than in the pretest (p < 0.05). Both feedback groups showed lower values in retention than in the pretest (p < 0.05). Even when the effect of feedback frequency could not be detected in motor learning, 67% of the feedback was recommended for motor adaptation.     

Effects of Different Ratios of Physical and Mental Practice on Postural Control Improvement

Abstract

Mental practice (MP) is a reliable alternative or complement to physical practice (PP) for the training of postural control. We address how MP should ideally be combined with PP. Participants were assigned to four experimental groups where MP/PP ratios during training varied from 0 to 100%. Performance improved only for demanding postural adjustments, regardless of MP/PP ratio, and learning was partially consolidated after a night of sleep. Findings reinforce the relevance of MP for the training of weight shifting and further suggest that MP alone can be as efficient as PP for the learning of certain complex postural adjustments.     

The Prediction of Negative Events Associated with Anxiety and Dietary Restraint: A Test of the Content Specificity Hypothesis

The prediction of future negative events was studied in a sample of undergraduate students varying on measures of anxiety and dietary restraint. Cognitive theories of psychopathology hypothesize that the emotional concerns of an individual determine which types of information are most often cognitively processed with a biased interpretation. This prediction has generally been called the content specificity hypothesis. Based upon this aspect of cognitive theory, we hypothesized that a high level of trait anxiety would be associated with higher ratings of the probability of future physically threatening events. In addition, it was hypothesized that a high level of dietary restraint would be associated with lower ratings of the probability of future occurrences of overeating. The results of the study supported these hypotheses. These prediction biases were found to be more pronounced in women, as compared to men. The findings were interpreted as supportive of the content specificity hypothesis.     

Interstimulus Intervals and Sensory Modality Modulate the Impact of a Cognitive Task on Postural Control

The present literature not only reveals the use of a wide variety of cognitive tasks but variability in their interaction with postural control. The question then arises, as to, whether postural control is sensitive to specific features of a cognitive task. The present experiment assessed the impact of cognitive tasks with interstimulus intervals (ISI) of varied duration and sensory modality on postural control in young adults. Seventeen participants (23.71 ± 1.99 years old) were instructed to stand on a force platform while concurrently performing cognitive tasks with ISIs of two and 5 s. The tasks were presented both, auditorily and visually. The visual tasks consisted of counting the total occurrence of a single digit. The auditory tasks consisted of counting the total occurrence of a single letter. Performing the cognitive tasks with an ISI of 2 s resulted only in an increase in the anteroposterior mean power frequency. Presenting the tasks visually also significantly reduced area of 95% confidence ellipse and AP and mediolateral sway variability. These results may suggest that ISIs can modify postural performance by altering the allocation of attentional focus. Also, presenting tasks using a visual sensory modality appears to yield lower postural sway.     

Postural Stability in Children with High Sacral Level Spina Bifida: Deviations from a Control Group

Abstract

Objective: To assess static and dynamic postural stability changes in children with high sacral level spina bifida.

Methods: Thirty-five children with high sacral level spina bifida and 35 age-matched healthy controls were enrolled. Their lower extremity muscle strengths and static and dynamic postural stability parameters were measured with the use of a dynamometer and the NeuroCom Balance Master^® device, respectively. Functional gait and balance were evaluated using the five times sit-to-stand test (5STS) and the 6-minute walk test (6MWT). Spinal, hip, and ankle deformities of the patient group were measured by radiologic evaluation.

Results: In comparison with controls, patients were found to have lower ankle dorsiflexion and plantar-flexion strength, increased 5STS duration, and decreased 6MWT distance while both static and dynamic postural stability parameters were significantly different. Bilateral ankle muscle strengths were found to be negatively correlated with postural stability parameters. The presence of hydrocephalus or meningomyelocele in the patient group was found to have negative effects on static postural stability.

Conclusion: Static and dynamic postural stability is affected even in children with high sacral level spina bifida who are expected to have best condition in this patient population. The ankle muscle strength is the main factor influencing these changes.     

研究专家行为的实验途径:一种质性方法

随着认知心理学对具体领域问题解决的研究不断深入,研究者越来越关注人的高级认知过程;而伴随这一研究倾向的变化．旨在揭示高胜任能力或者专家行为的实质及其发展的科学研究方法也逐渐成形;本文介绍了选择符合科学研究的专家行为标准,即有效性、可重复性和可测量性;之后,详述了研究专家行为的步骤．即选择被试、明确典型任务、进行任务分析、设计研究方案、收集原始资料、分析原始资料和解释专家行为等。这一方法的阐述．为心理学工作者使用该方法提供了一类规范。     

Four Weeks of Neuromuscular Training Improve Static and Dynamic Postural Control in Overweight and Obese Children: A Randomized Controlled Trial

Abstract

Thirty-two children with overweight or obesity were randomly divided into a neuromuscular training group (NTG) (n = 16) and a control group (CG) (n = 16). All individuals participated in the measurement of static postural control under two conditions: the double-leg stance with eyes open (EO) and eyes closed (EC). The center of pressure variables was obtained. mSEBT was used for dynamic postural control. Neuromuscular training was performed twice per week and lasted 4 weeks. The results of this study indicate that 4 weeks of neuromuscular training improve static and dynamic postural control in children with excess body weight.     

MA and Togetherness (Ittaikan) in the Narratives of Dancers and Spectators: Sharing an Uncertain Space

The Japanese concept/character MA (間), commonly translated as “gap, interval, or the in between,” partakes in many forms of Japanese arts and daily-life practices. In this article, we report the results of a qualitative research on the meaning or experience of MA and its relation with the feeling of togetherness in the context of contemporary dance improvisation. We interviewed performers and spectators (all professional dancers) while they watched the videotaped and reduced stick-figure versions of short dance improvisations created in a laboratory installed with motion-capture sensors. Based on the individual narratives, and inspired by Japanese and occidental aesthetic writings, we elaborate a specific understanding of MA as attending to the event's preacceleration, and how this experience causally relates to the feeling of togetherness (一体感, ittaikan). We propose that MA, understood not extensionally (as an empty space or a silent gap), but intentionally/internally as a certain quality of attention or perceptual mode, is fertile ground for serendipity. MA as an interpersonal ethical construct suggests a transsubjective difference as a foundation for a collective coming together.     

The Influence of an Acute Bout of Whole Body Vibration on Human Postural Control Responses

The use of vibrating platforms has become increasingly available, and popular at sports and rehabilitation institutes. Given the discrepancies in the literature regarding whole body vibration (WBV) and human reflexive responses, the purpose of this study was to examine the acute effects of WBV on postural response latencies, as well as associated electromyography measures of the lower extremities during balance perturbations. Reflexive responses during backward and forward balance perturbations were examined before, after, and 10 min after a bout of WBV. The findings suggest that following an acute bout of whole body vibration, muscle activity of the lower extremities is decreased during a reflexive response to an unexpected perturbation, and may be associated with faster reaction time.     

The Stationary-Gaze Task Should Not Be Systematically Used as the Control Task in Studies of Postural Control

In studies of postural control, a control task is often used to understand significant effects obtained with experimental manipulations. This task should be the easiest task and (therefore) engage the lowest behavioral variability and cognitive workload. Since 1983, the stationary-gaze task is considered as the most relevant control task. Instead, the authors expected that free looking at small targets (white paper or images; visual angle: 12°) could be an easier task. To verify this assumption, 16 young individuals performed stationary-gaze, white-panel, and free-viewing 12° tasks in steady and relaxed stances. The stationary-gaze task led to significantly higher cognitive workload (mean score in the National Aeronotics and Space Administration Task Load Index questionnaire), higher interindividual body (head, neck, and lower back) linear variability, and higher interindividual body angular variability—not systematically yet—than both other tasks. There was more cognitive workload in steady than relaxed stances. The authors also tested if a free-viewing 24° task could lead to greater angular displacement, and hence greater body sway, than could the other tasks in relaxed stance. Unexpectedly, the participants mostly moved their eyes and not their body in this task. In the discussion, the authors explain why the stationary-gaze task may not be an ideal control task and how to choose this neutral task.     

Regressive Imagery in Creative Problem‐Solving: Comparing Verbal Protocols of Expert and Novice Visual Artists and Computer Programmers

We applied computer‐based text analyses of regressive imagery to verbal protocols of individuals engaged in creative problem‐solving in two domains: visual art (23 experts, 23 novices) and computer programming (14 experts, 14 novices). Percentages of words involving primary process and secondary process thought, plus emotion‐related words, were tabulated. Visual art protocols were higher in primary process thought and emotion‐related words; those from programming were higher in secondary process thought. Almost no main effects of expertise or interactions were found. Correlations between the measures (particularly those involving emotion‐related words) also varied as a function of task. This pattern suggests cognitive processes vary considerably across different creative problem‐solving tasks or domains, and that a more domain‐specific approach to creative cognition may be advisable. Further implications for integrating and consolidating some extant lines of creativity research are discussed.