Whole-body angular momentum in a complex dance sequence: Differences across skill levels

Due to the redundant degrees of freedom (DOF) and nonlinearity of reactional kinetic elements within the human motor apparatus, controlling the complex dynamics of the human musculoskeletal system presents considerable difficulties. Based on this challenge, Bernstein (1967) viewed skill development as the process whereby the central nervous system (CNS) gains mastery of kinematic DOF and kinetic reactional elements (passive forces, moments etc.), with the highest level of skill characterised by optimal exploitation of reactional elements in the achievement of movement goals. A previous kinematic investigation into coordination differences in a complex multidirectional dance sequence demonstrated that general unfreezing of kinematic DOF occurred as dance skill progressed (Chang et al., submitted for publication). To gain insight into the role of angular reactional elements in skill, the present kinetic study investigated angular momentum and associated variables across three skill levels (beginners, intermediates, experts) within this same complex dance sequence. The results showed that the angular momenta of segments and accompanying angular reactional elements generally increased with skill level. More specifically, the findings suggested that while improvements in movement economy from cancellation of angular momentum between body segments occur early in skill progression, later in skill progression, experts utilise increased whole-body angular momentum. Although this is energetically expensive, it may enhance the aesthetic value of dance movements, and/or have mechanical advantages. Overall, the findings here provide support for Bernstein’s (1967) model of skill development. Future research should quantify the relations between energy expenditure, key biomechanical variables that reflect skill and dance aesthetics as perceived by audiences.     

Visuo-tactile congruency influences the body schema during full body ownership illusion

Previous research showed that full body ownership illusions in virtual reality (VR) can be robustly induced by providing congruent visual stimulation, and that congruent tactile experiences provide a dispensable extension to an already established phenomenon. Here we show that visuo-tactile congruency indeed does not add to already high measures for body ownership on explicit measures, but does modulate movement behavior when walking in the laboratory. Specifically, participants who took ownership over a more corpulent virtual body with intact visuo-tactile congruency increased safety distances towards the laboratory’s walls compared to participants who experienced the same illusion with deteriorated visuo-tactile congruency. This effect is in line with the body schema more readily adapting to a more corpulent body after receiving congruent tactile information. We conclude that the action-oriented, unconscious body schema relies more heavily on tactile information compared to more explicit aspects of body ownership.     

A predictive coding model of gaze shifts and the underlying neurophysiology

A comprehensive model of gaze control must account for a number of empirical observations at both the behavioural and neurophysiological levels. The computational model presented in this article can simulate the coordinated movements of the eye, head, and body required to perform horizontal gaze shifts. In doing so it reproduces the predictable relationships between the movements performed by these different degrees of freedom (DOFs) in the primate. The model also accounts for the saccadic undershoot that accompanies large gaze shifts in the biological visual system. It can also account for our perception of a stable external world despite frequent gaze shifts and the ability to perform accurate memory-guided and double-step saccades. The proposed model also simulates peri-saccadic compression: the mis-localization of a briefly presented visual stimulus towards the location that is the target for a saccade. At the neurophysiological level, the proposed model is consistent with the existence of cortical neurons tuned to the retinal, head-centred, body-centred, and world-centred locations of visual stimuli and cortical neurons that have gain-modulated responses to visual stimuli. Finally, the model also successfully accounts for peri-saccadic receptive field (RF) remapping which results in reduced responses to stimuli in the current RF location and an increased sensitivity to stimuli appearing at the location that will be occupied by the RF after the saccade. The proposed model thus offers a unified explanation for this seemingly diverse range of phenomena. Furthermore, as the proposed model is an implementation of the predictive coding theory, it offers a single computational explanation for these phenomena and relates gaze shifts to a wider framework for understanding cortical function.     

Cross-association analysis of EEG and EMG signals according to movement intention state

Rehabilitation within three months plays a significant role in the recovery of damaged motor functions following the onset of a stroke. To increase the effectiveness of rehabilitation, it is important to perform rehabilitative exercises with movement intention. This study analyzed the association between electroencephalogram (EEG) and electromyogram (EMG) signals in healthy individuals in an attempt to verify the differences between the two signals in corticomuscular connectivity as well as the time delay in the flow of information in accordance with the presence of movement intention. To examine the relationship between the brain and muscles, coherence and mutual information analyses were performed on the EEG signals in the motor cortex and EMG signals in the flexor digitorum superficialis muscle during grasping training. Coherence and mutual information between EEG and EMG signals were significantly higher and the time delay of information flow was shorter when subjects performed active exercise with movement intention than when they performed passive exercise without movement intention. These findings could be applied to the rehabilitation of stroke patients to develop a rehabilitative training system with heightened effectiveness through verification of the presence of movement intention in the patients.     

Making Critically Conscious Disciples: A Zambian Pentecostal Pneumato‐Discipleship Missiology

This article calls for rethinking of discipleship within missio Spiritus for political formation necessary for the viable functioning of Zambian Pentecostalism in the neo‐colonial context. It argues that the theme for the 2018 World Mission Conference in Arusha, Tanzania, “Moving in the Spirit: Called to Transforming Discipleship,” calls for pneumato‐discipleship in promoting human dignity. Through an empirical missiological approach, the article analyzes interviews conducted with various believers in various Pentecostal communities to demonstrate the emerging missio Spiritus praxis among Zambian Pentecostals, which seeks to promote a missional ethics of resistance to neo‐colonial political culture. Pneumato‐discipleship, as pedagogy for critically conscious disciples, is geared toward realization of human dignity. It is the instrument of hope in the search for dignity and struggle against pervasive inhumanities.     

Neuroimaging and Occupational Therapy: Bridging the Gap to Advance Rehabilitation in Developmental Coordination Disorder

Developmental coordination disorder (DCD) is a neurodevelopmental disorder characterized by poor motor skills that interfere with a child's ability to perform everyday activities. Little is known about the neural mechanisms that implicate DCD, making it difficult to understand why children with DCD struggle to learn motor skills and selecting the best intervention to optimize function. Neuroimaging studies that utilize magnetic resonance imaging techniques have the capacity to play a critical role in helping to guide clinicians to optimize functional outcomes of children with DCD using evidence-based rehabilitation interventions. The authors' goal is to describe how neuroimaging research can be applied to occupational therapy and rehabilitation sciences by highlighting projects that are at the forefront of the field and elucidate future directions.     

A Direct-Learning Approach to Acquiring a Bimanual Tapping Skill

The theory of direct learning (D. M. Jacobs &; C. F. Michaels, 2007 Jacobs, D. M., &; Michaels, C. F. (2007). Direct learning. Ecological Psychology, 19, 321–349.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) has proven useful in understanding improvement in perception and exploratory action. Here the authors assess its usefulness for understanding the learning of a motor skill, bimanual tapping at a difficult phase relation. Twenty participants attempted to learn to tap with 2 index fingers at 2 Hz with a phase lag of 90° (i.e., with a right-right period of 500 ms and a right-left period of 125 ms). There were 30 trials, each with 50 tapping cycles. Computer-screen feedback informed of errors in both period and phase for each pair of taps. Participants differed dramatically in their success. Learning was assessed by identifying the succession of attractors capturing tapping over the experiment. A few participants’ attractors migrated from antiphase to 90° with an appropriate period; others became attracted to a fixed right-left interval, rather than phase, with or without attraction to period. Changes in attractor loci were explained with mixed success by direct learning, inviting elaboration of the theory. The transition to interval attractors was understood as a change in intention, and was remarkable for its indifference to typical bimanual interactions.     

五四新文化运动与孔子观念的根本转折

五四新文化运动中的孔子观念需作系统的梳理与分析。五四新文化运动的健将们主要是基于对尊孔派的反感和伦理、文化上的彻底觉悟而发起了对孔子与孔家店集中而猛烈的批评与攻击。他们所批判的主要是孔子的偶像 ,而并不反对孔子本人 ,破除孔子偶像的束缚而使人们的思想从权威和偏见中彻底解放出来 ,这是新文化运动最重要的历史功绩 ;他们虽不反对孔子本人 ,但对孔子与孔子之道采取的是一种社会语境决定论的或历史化的诠释与读解的态度 ,故带来了孔子观念的根本转折。     

陈独秀伦理革命评析

陈独秀在“五四”新文化运动中倡导的伦理革命在其思想理论体系中占有独特地位 ,对其伦理革命的思想进行评析 ,能够为我们今天的道德建设提供许多有益的启示。     

The Embodiment Thesis

In this essay I articulate and defend a thesis about the nature of morality called “the embodiment thesis”. The embodiment thesis states that moral values underdetermine the obligations and entitlements of individual persons, and that actual social institutions must embody morality by specifying these moral relations. I begin by presenting two thought experiments that elucidate and motivate the embodiment thesis. I then proceed by distinguishing the embodiment thesis from a Rawlsian doctrine about the nature of justice, from the doctrine of moral relativism, and from solutions to the coordination problem of rational choice theory.