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  • Doing It Your Way: How Individual Movement Styles Affect Action Prediction

    http://journals.plos.org/plosone/art...l.pone.0165297

    Abstract

    Individuals show significant variations in performing a motor act. Previous studies in the action observation literature have largely ignored this ubiquitous, if often unwanted, characteristic of motor performance, assuming movement patterns to be highly similar across repetitions and individuals. In the present study, we examined the possibility that individual variations in motor style directly influence the ability to understand and predict others’ actions. To this end, we first recorded grasping movements performed with different intents and used a two-step cluster analysis to identify quantitatively ‘clusters’ of movements performed with similar movement styles (Experiment 1). Next, using videos of the same movements, we proceeded to examine the influence of these styles on the ability to judge intention from action observation (Experiments 2 and 3). We found that motor styles directly influenced observers’ ability to ‘read’ others’ intention, with some styles always being less ‘readable’ than others. These results provide experimental support for the significance of motor variability for action prediction, suggesting that the ability to predict what another person is likely to do next directly depends on her individual movement style.
    Introduction

    Understanding others’ intentions is a prerequisite for successful social interaction [1]. But how do we understand the intentions of other people? Is it possible to understand the intentions of others by simply observing their movements? Few studies have directly assessed the ability to judge intention from movement and results have been mixed [2,3]. Some studies report observers to be able to discriminate intentions from the observation of early differences in movement kinematics [4,5]. In keeping with this notion, for example, [4] showed that, by simply observing grasping movements, observers were able to judge whether the agent’s intent in grasping the object was to cooperate with a partner or compete against an opponent. Other studies, however, did not confirm such advance information pickup from others’ grasping patterns. For example, [6] found that observers were not able to predict whether an object was going to be brought to the mouth or placed on the table until they had seen at least part of the post-grasp movement—a finding that was taken to suggest that they did not detect early kinematic differences to predict the outcome of observed actions.

    Central to being able to interpret these apparently contradictory results is the understanding of the relationship between the specific features of observed movements and the capacity to discriminate intention. Prior studies have largely ignored variations in motor performance, assuming movement features to be similar across trials and individuals. Repeatedly performing a movement, however, does not result in the same motor output on every attempt. More importantly, in performing the same task, outputs of the motor system may vary substantially from one individual to another [7]. Individual variations in movement patterns have been documented in a wide variety of animals [8], as well in humans [9]. For example, individuals have been shown to use their own unique set of motor synergies, which varies in both structure and number, but is consistent across different motor tasks and over a period of weeks [10]. While differences in anatomy may contribute to such variations, it is likely that motor exploration, experience, and training also influence subject-specific muscle strategies, leading to dissimilar kinematic patters for achieving an equivalent goal.

    One issue that research on action observation has not considered until now is whether differences in movement style influence action understanding. Some movement styles may facilitate understanding of others’ intention, whereas others may make it more difficult. If so, the mixed results regarding intention-from-movement understanding may reflect, at least in part, differences in the individual style of the observed movements.
    Jo Bowyer
    Chartered Physiotherapist Registered Osteopath.
    "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

    Comment


    • An Automated Recording Method in Clinical Consultation to Rate the Limp in Lower Limb Osteoarthritis

      http://journals.plos.org/plosone/art...l.pone.0164975

      Abstract

      For diagnosis and follow up, it is important to be able to quantify limp in an objective, and precise way adapted to daily clinical consultation. The purpose of this exploratory study was to determine if an inertial sensor-based method could provide simple features that correlate with the severity of lower limb osteoarthritis evaluated by the WOMAC index without the use of step detection in the signal processing. Forty-eight patients with lower limb osteoarthritis formed two severity groups separated by the median of the WOMAC index (G1, G2). Twelve asymptomatic age-matched control subjects formed the control group (G0). Subjects were asked to walk straight 10 meters forward and 10 meters back at self-selected walking speeds with inertial measurement units (IMU) (3-D accelerometers, 3-D gyroscopes and 3-D magnetometers) attached on the head, the lower back (L3-L4) and both feet. Sixty parameters corresponding to the mean and the root mean square (RMS) of the recorded signals on the various sensors (head, lower back and feet), in the various axes, in the various frames were computed. Parameters were defined as discriminating when they showed statistical differences between the three groups. In total, four parameters were found discriminating: mean and RMS of the norm of the acceleration in the horizontal plane for contralateral and ipsilateral foot in the doctor’s office frame. No discriminating parameter was found on the head or the lower back. No discriminating parameter was found in the sensor linked frames. This study showed that two IMUs placed on both feet and a step detection free signal processing method could be an objective and quantitative complement to the clinical examination of the physician in everyday practice. Our method provides new automatically computed parameters that could be used for the comprehension of lower limb osteoarthritis. It may not only be used in medical consultation to score patients but also to monitor the evolution of their clinical syndrome during and after rehabilitation. Finally, it paves the way for the quantification of gait in other fields such as neurology and for monitoring the gait at a patient’s home.
      Jo Bowyer
      Chartered Physiotherapist Registered Osteopath.
      "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

      Comment


      • Dependence of Gait Deviation on Weight-Bearing Asymmetry and Postural Instability in Children with Unilateral Cerebral Palsy

        http://journals.plos.org/plosone/art...l.pone.0165583

        Abstract

        Postural control deficits have been suggested to be a major component of gait disorders in children with cerebral palsy. The purpose of this study was to investigate the relationship between postural stability and treadmill walking, in children with unilateral cerebral palsy, by defining dependence between the posturographic weight-bearing distribution and center of pressure (CoP) sway during quiet standing with Gillette Gait Index and the 16 distinct gait parameters that composed the Gillette Gait Index. Forty-five children with unilateral cerebral palsy from 7–12 years of age were included in this study. A posturographic procedure and 3-dimensional instrumented gait analysis was developed. In general, across the entire tested group, the significant correlations concerned only the asymmetry of the weight bearing and a few of the distinct gait parameters that compose the Gillette Gait Index; moreover, correlation coefficients were low. The division of subjects into two clinical subgroups: children that exhibited a tendency to overload (1) and to underload (2) the affected body side, modified the results of the explored relationships. Our findings revealed that the difficulties experienced by children with hemiplegia while controlled in a standing position result from tendency to excessively or insufficiently load the affected lower limbs, and thus establishes a direct relationship with inadequate affected peak ankle DF in both stance and swing gait phases. Given the presented relationship between postural instability and deviation of the particular gait parameters in children with unilateral cerebral palsy, a follow-up study will be needed to determine the therapeutic approaches that will be most effective in promoting increased improvement in gait pattern, as well as the static and dynamic balance in standing.
        Introduction

        Postural control ensures the proper positioning of the body in space and maintains stability and body alignment by keeping the projection of the center of pressure (CoP) within the limits of the support base [1]. In the case of cerebral palsy (CP), postural controls are impaired according to the site and extent of brain damage [2–8].

        Postural control deficits have been suggested to be a major component of gait disorders in CP [6,9–12]; however, the relationship between standing balance and walking function has rarely been investigated. Although the literature has highlighted the relationship between postural control and functionality, there is limited information regarding the relationship between postural control and walking, and it is not clear which parameter of standing balance correlates with which gait parameter.


        The Effects of Selective Dorsal Rhizotomy on Balance and Symmetry of Gait in Children with Cerebral Palsy

        http://journals.plos.org/plosone/art...l.pone.0152930

        Abstract

        Aim

        Cerebral palsy (CP) is associated with dysfunction of the upper motor neuron and results in balance problems and asymmetry during locomotion. Selective dorsal rhizotomy (SDR) is a surgical procedure that results in reduced afferent neuromotor signals from the lower extremities with the aim of improving gait. Its influence on balance and symmetry has not been assessed. The aim of this prospective cohort study was to evaluate the impact of SDR on balance and symmetry during walking.

        Methods

        18 children (10 girls, 8 boys; age 6 years (y) 3 months (m), SD 1y 8m) with bilateral spastic CP and Gross Motor Function Classification System levels I to II underwent gait analysis before and 6 to 12 months after SDR. Results were compared to 11 typically developing children (TDC; 6 girls, 5 boys; age 6y 6m, SD 1y 11m). To analyse balance, sway velocity, radial displacement and frequency were calculated. Symmetry ratios were calculated for balance measures and spatio-temporal parameters during walking.

        Results

        Most spatio-temporal parameters of gait, as well as all parameters of balance, improved significantly after SDR. Preoperative values of symmetry did not vary considerably between CP and TDC group and significant postoperative improvement did not occur.

        Interpretation

        The reduction of afferent signalling through SDR improves gait by reducing balance problems rather than enhancing movement symmetry.
        Update 09/05/2017
        Last edited by Jo Bowyer; 09-05-2017, 10:53 AM.
        Jo Bowyer
        Chartered Physiotherapist Registered Osteopath.
        "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

        Comment


        • Absolute and Relative Reliability of the Timed ‘Up & Go’ Test and ‘30second Chair-Stand’ Test in Hospitalised Patients with Stroke

          http://journals.plos.org/plosone/art...l.pone.0165663

          Abstract

          Objective

          The timed ‘Up & Go’ test and ‘30second Chair-Stand’ test are simple clinical outcome measures widely used to assess functional performance. The reliability of both tests in hospitalised stroke patients is unknown. The purpose was to investigate the relative and absolute reliability of both tests in patients admitted to an acute stroke unit.

          Methods

          Sixty-two patients (men, n = 41) attended two test sessions separated by a one hours rest. Intraclass correlation coefficients (ICC2,1) were calculated to assess relative reliability. Absolute reliability was expressed as Standard Error of Measurement (with 95% certainty—SEM95) and Smallest Real Difference (SRD) and as percentage of their respective means if heteroscedasticity was observed in Bland Altman plots (SEM95% and SRD%).

          Results

          ICC values for interrater reliability were 0.97 and 0.99 for the timed ‘Up & Go’ test and 0.88 and 0.94 for ‘30second Chair-Stand’ test, respectively. ICC values for intrarater reliability were 0.95 and 0.96 for the timed ‘Up & Go’ test and 0.87 and 0.91 for ‘30second Chair-Stand’ test, respectively. Heteroscedasticity was observed in the timed ‘Up & Go’ test. Interrater SEM95% ranged from 9.8% to 14.2% with corresponding SRD% of 13.9–20.1%. Intrarater SEM95% ranged from 15.8% to 18.7% with corresponding SRD% of 22.3–26.5%. For ‘30second Chair-Stand’ test interrater SEM95 ranged between 1.5 and 1.9 repetitions with corresponding SRD of 2 and 3 and intrarater SEM95 ranged between 1.8 and 2.0 repetitions with corresponding SRD values of 3.

          Conclusion

          Excellent reliability was observed for the timed ‘Up & Go’ test and the ‘30second Chair-Stand’ test in hospitalised stroke patients. The thresholds to detect a real change in performance were 18.7% for the timed ‘Up & Go’ test and 2.0 repetitions for the ‘30second Chair-Stand’ in groups of patients and 26.5% and 3 repetitions in individual patients, respectively.
          Jo Bowyer
          Chartered Physiotherapist Registered Osteopath.
          "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

          Comment


          • The attention habit: how reward learning shapes attentional selection

            http://onlinelibrary.wiley.com/doi/1...yas.12957/full

            Abstract

            There is growing consensus that reward plays an important role in the control of attention. Until recently, reward was thought to influence attention indirectly by modulating task-specific motivation and its effects on voluntary control over selection. Such an account was consistent with the goal-directed (endogenous) versus stimulus-driven (exogenous) framework that had long dominated the field of attention research. Now, a different perspective is emerging. Demonstrations that previously reward-associated stimuli can automatically capture attention even when physically inconspicuous and task-irrelevant challenge previously held assumptions about attentional control. The idea that attentional selection can be value driven, reflecting a distinct and previously unrecognized control mechanism, has gained traction. Since these early demonstrations, the influence of reward learning on attention has rapidly become an area of intense investigation, sparking many new insights. The result is an emerging picture of how the reward system of the brain automatically biases information processing. Here, I review the progress that has been made in this area, synthesizing a wealth of recent evidence to provide an integrated, up-to-date account of value-driven attention and some of its broader implications.
            Running commentary and praise go a long way when teaching movement to those who have forgotten the basics, often the visual system as well as proprioception, kinaesthetic awareness and vestibular issues have to be factored in, as well as cognitive difficulties and simple inability to focus on the task, due to short attention span.
            Jo Bowyer
            Chartered Physiotherapist Registered Osteopath.
            "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

            Comment


            • Sensory feedback synchronizes motor and sensory neuronal networks in the neonatal rat spinal cord

              http://www.nature.com/articles/ncomms13060

              Abstract
              Early stages of sensorimotor system development in mammals are characterized by the occurrence of spontaneous movements. Whether and how these movements support correlated activity in developing sensorimotor spinal cord circuits remains unknown. Here we show highly correlated activity in sensory and motor zones in the spinal cord of neonatal rats in vivo. Both during twitches and complex movements, movement-generating bursts in motor zones are followed by bursts in sensory zones. Deafferentation does not affect activity in motor zones and movements, but profoundly suppresses activity bursts in sensory laminae and results in sensorimotor uncoupling, implying a primary role of sensory feedback in sensorimotor synchronization. This is further supported by largely dissociated activity in sensory and motor zones observed in the isolated spinal cord in vitro. Thus, sensory feedback resulting from spontaneous movements is instrumental for coordination of activity in developing sensorimotor spinal cord circuits.
              Jo Bowyer
              Chartered Physiotherapist Registered Osteopath.
              "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

              Comment


              • How to Measure the Psychological “Flow”? A Neuroscience Perspective

                http://journal.frontiersin.org/artic...016.01823/full

                Introduction
                The term “flow” as conceptualized by Csikszentmihalyi (1975) describes the optimal experiences that are most enjoyable in human life while fully engaging in an activity (Csikszentmihalyi, 1978, 1990, 1998). Within athletic, artistic and occupational behaviors, the flow emerges from an action that requires specific skills and challenges (Marin and Bhattacharya, 2013). It also expands self-esteem and the individual's capabilities through learning new optimizations that increase the feelings of continuity and fluidity in attention and action. The flow does not occur for all types of behavior. It requires clear goals, unambiguous and immediate feedback, assuming a perfect match between skills and challenge (Mao et al., 2016).

                In contrast to its behavioral counterpart, commonly expressed by the term “stress,” the flow may be viewed as a convergent physiological entity supported by the emergence of a unique brain state. Since flow requires challenges, it must be supported by short-term stress (the good one) that assumes physiological protection (e.g., enhancement of immunoprotection) to deal with challenges. On the contrary, long-term stress (chronic) impinges on reaching the flow state and disrupts the immunoprotective effects on various physiological functions (Dhabhar, 2014). Because of the conjunction of action skill, challenge and emotion in a single flow-state, the scientific community remains confronted with the complex question of identifying its neurophysiological outcomes. This challenge is in line with the unresolved questions relating neurometric-psychometric comparisons in an attempt to identify neurophysiological activities and sensations (Stüttgen et al., 2011) that occur during the flow.

                In this Grand Challenges monograph, my intent is to trace experimental perspectives applying tools of movement neuroscience (Cheron, 2015; Cheron et al., 2016) in order to characterize the physiological aspects of the brain state during flow in sports.
                There is absolutely no reason why a flow state cannot be achieved in rehab, in fact it is essential to point out to performers that it can and should be achievable. When I worked more than I do now in sport, I was asked to see actors, dancers, musicians and singers. Walking down a runway during Fashion Week is performance art, as is making a speech in parliament. Teaching is performance art, as is interacting with your public when you are at work in a supermarket. Teenagers "get it" once it is explained, small children don't need it explained.

                I prescribe activities of daily living for movement and loading. Stacking shelves could be so much more than many who do it for a living realise, until it is pointed out to them.





                Creative Flow as a Unique Cognitive Process

                http://journal.frontiersin.org/artic...017.01348/full

                Update 26/07/2017
                Last edited by Jo Bowyer; 26-07-2017, 08:27 PM.
                Jo Bowyer
                Chartered Physiotherapist Registered Osteopath.
                "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                Comment


                • An Embodied Approach to Understanding: Making Sense of the World Through Simulated Bodily Activity

                  http://journal.frontiersin.org/artic...016.01914/full

                  Even though understanding is a very widely used concept, both colloquially and in scholarly work, its definition is nebulous and it is not well-studied as a psychological construct, compared to other psychological constructs like learning and memory. Studying understanding based on third-person (e.g., behavioral, neuroimaging) data alone presents unique challenges. Understanding refers to a first-person experience of making sense of an event or a conceptual domain, and therefore requires incorporation of multiple levels of study, at the first-person (phenomenological), behavioral, and neural levels. Previously, psychological understanding was defined as a form of conscious knowing. Alternatively, biofunctional approach extends to unconscious, implicit, automatic, and intuitive aspects of cognition. Here, to bridge these two approaches an embodied and evolutionary perspective is provided to situate biofunctional understanding in theories of embodiment, and to discuss how simulation theories of cognition, which regard simulation of sensorimotor and affective states as a central tenet of cognition, can bridge the gap between biofunctional and psychological understanding.

                  Understanding is a widely used but an ill-defined concept. Colloquially it refers to meta awareness or conscious monitoring of a mental state that involves making sense of a situation or an event. It also implies a parity between one’s own mental model (e.g., of a phenomenon), and another person’s mental model (e.g., “I understand what you mean”) or an external entity that represents a model (e.g., “I understand what the text says”). Educators often use the term understanding as part of the goal statement of an instructional program or intervention to imply a deep form of learning, where what is understood is internalized and becomes readily available for future interpretation of events and decision making. In spite of the wide use of the term both in colloquial and academic language, understanding is not subject to scientific study in cognitive sciences and education to the extent that other mainstream constructs are, such as perception, learning, memory and executive function. This essay focuses on one approach to understanding, the biofunctional one, and situates biofunctional understanding in a wider embodied cognition framework, in an effort to reinterpret understanding as a bodily state (as opposed to a mere mental state), and to situate understanding as an evolutionary outcome; a response to the pressures of living in a time-pressured environment.

                  Biofunctionalism defines understanding as the special function of the distributed biological activity in the various subsystems of the agent’s nervous system and the immediate source of an agent’s ongoing living experience (Iran-Nejad, 2013). Understanding is not a conscious construction or acquisition of mental structures that act as models of the outside world. Rather, it is an adaptive change at the biological level as a result of situated activity. It happens even when we are not consciously paying attention to what we do. In this sense, it is like breathing (Iran-Nejad, 2013). It can be controlled and structured with conscious reflection, but it also lingers in an automatic, unconscious way. In contrast with the cognitivist characterization of understanding as acquiring permanent and abstract representations in the long-term memory, biofunctionalism defines understanding as a dynamic process where cognitive patterns elicited during understanding are transient and dynamic.

                  In this paper a biofunctionalist account for understanding is situated in empirical and theoretical embodied cognition research. The overall purpose is to support the following four arguments on understanding based on theories of embodiment and empirical work on bodily foundations of cognition:

                  (1) Understanding is biological. It is an adaptive evolutionary response to living in a time-pressured and dynamic environment.

                  (2) Understanding is experiential. Understanding does not follow acquisition of permanent and abstract mental representations, it is a result of situated activity.

                  (3) Understanding involves acquisition reactivation of transient sensorimotor and affective states.

                  (4) Biofunctional understanding is a prerequisite for psychological understanding (Iran-Nejad, 2013). Simulated multi-modal activity actualizes biofunctional understanding which, in turn, underlies psychological understanding. Psychological understanding makes use of perceptual symbols systems (Barsalou, 1999, 2008) to consciously access and structure biofunctional understanding.

                  These arguments are not separately considered here since they are all interrelated. Instead, the discussion is structured around theories of embodiment in the most salient domains of human cognition for “understanding” (i.e., social cognition and verbal skills, manual skills and tool use, and metaphorical thinking). The reflection on these three domains unfold the necessary theoretical implements to ground a biofunctional account for understanding in embodied cognition.
                  I have put this here because it follows on nicely from my comments on the above paper.

                  Would we have to explain embodiment to a nineteenth century farm labourer scything barley? No one I saw this morning was embodied and I live and do some of my work in what was once a rural area. Their great grand parents probably were.



                  Does movement influence representations of time and space?
                  http://journals.plos.org/plosone/art...l.pone.0175192

                  Abstract

                  Embodied cognition posits that abstract conceptual knowledge such as mental representations of time and space are at least partially grounded in sensorimotor experiences. If true, then the execution of whole-body movements should result in modulations of temporal and spatial reference frames. To scrutinize this hypothesis, in two experiments participants either walked forward, backward or stood on a treadmill and responded either to an ambiguous temporal question (Experiment 1) or an ambiguous spatial question (Experiment 2) at the end of the walking manipulation. Results confirmed the ambiguousness of the questions in the control condition. Nevertheless, despite large power, walking forward or backward did not influence the answers or response times to the temporal (Experiment 1) or spatial (Experiment 2) question. A follow-up Experiment 3 indicated that this is also true for walking actively (or passively) in free space (as opposed to a treadmill). We explore possible reasons for the null-finding as concerns the modulation of temporal and spatial reference frames by movements and we critically discuss the methodological and theoretical implications.
                  Introduction

                  “Space, motion, and time cannot be elucidated by discovering an 'inner' layer of experience in which their multiplicity is erased and really abolished. For if this happens, neither space, nor movement, nor time remains…” [1].

                  What seemed clear to the French philosopher Merleau-Ponty already in 1945 [1], is surprisingly often neglected in psychological research about temporal and spatial representations in humans: Our knowledge of the mechanisms underlying temporal and spatial representations is incomplete without understanding their relation with movement. Indeed, the majority of studies in different research areas such as neurosciences, linguistics, and cognition (for overviews from different perspectives see e.g., [2,3]) focus on the relatedness between time and space, but often do not consider the influential role of movement. To this end, the current study aims at examining the impact of movements on the construction of temporal and spatial representations
                  Update 05/04/2017



                  The Neuromuscular Origins of Kinematic Variability during Perturbed Walking

                  https://www.nature.com/articles/s41598-017-00942-x

                  Abstract
                  We investigated the neuromuscular contributions to kinematic variability and thus step to step adjustments in posture and foot placement across a range of walking speeds in response to optical flow perturbations of different amplitudes using a custom virtual environment. We found that perturbations significantly increased step width, decreased step length, and elicited larger trunk sway compared to normal walking. However, perturbation-induced effects on the corresponding variabilities of these measurements were much more profound. Consistent with our hypotheses, we found that: (1) perturbations increased EMG activity of the gluteus medius and postural control muscles during leg swing, and increased antagonist leg muscle coactivation during limb loading in early stance, and (2) changes in the magnitude of step to step adjustments in postural sway and lateral foot placement positively correlated with those of postural control and gluteus medius muscle activities, respectively, in response to perturbations. However, (3) interactions between walking speed and susceptibility to perturbations, when present, were more complex than anticipated. Our study provides important mechanistic neuromuscular insight into walking balance control and important reference values for the emergence of balance impairment.
                  Update 21/04/2017
                  Last edited by Jo Bowyer; 21-04-2017, 10:05 AM.
                  Jo Bowyer
                  Chartered Physiotherapist Registered Osteopath.
                  "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                  Comment


                  • Differential Training Facilitates Early Consolidation in Motor Learning

                    http://journal.frontiersin.org/artic...016.00199/full

                    Current research demonstrates increased learning rates in differential learning (DL) compared to repetitive training. To date, little is known on the underlying neurophysiological processes in DL that contribute to superior performance over repetitive practice. In the present study, we measured electroencephalographic (EEG) brain activation patterns after DL and repetitive badminton serve training. Twenty-four semi-professional badminton players performed badminton serves in a DL and repetitive training schedule in a within-subjects design. EEG activity was recorded from 19 electrodes according to the 10–20 system before and immediately after each 20-min exercise. Increased theta activity was obtained in contralateral parieto-occipital regions after DL. Further, increased posterior alpha activity was obtained in DL compared to repetitive training. Results indicate different underlying neuronal processes in DL and repetitive training with a higher involvement of parieto-occipital areas in DL. We argue that DL facilitates early consolidation in motor learning indicated by post-training increases in theta and alpha activity. Further, brain activation patterns indicate somatosensory working memory processes where attentional resources are allocated in processing of somatosensory information in DL. Reinforcing a somatosensory memory trace might explain increased motor learning rates in DL. Finally, this memory trace is more stable against interference from internal and external disturbances that afford executively controlled processing such as attentional processes.
                    Introduction
                    Understanding how to make motor learning more efficient and effective is an important goal in behavioral neuroscience. The application of variable practice has achieved acceptance as being beneficial for motor learning processes. Numerous studies have demonstrated enhanced motor learning performance in variable practice over repetitive learning schedules (for an overview see Beckmann, 2013). An important research question in literature raises the discussion on type, schedule and amount of variation to be applied in motor learning settings. Different training schedules and degrees of variations have been suggested for varied acquisition in the context of motor learning. First, models of variation were included in methodical rows of exercises whereby the motor task is approached by exercises that become subsequently more similar to the goal task (Gaulhofer and Streicher, 1924). Based on the theoretical assumption that similar movements can be condensed into classes of movements that can be modeled by means of invariants and variable parameters (Schmidt, 1975), varied training with the same invariants and several variable parameters was suggested to result in more stable generalized motor programs, and therefore with superior performance in retention and transfer of the learned motor task (Moxley, 1979).

                    A different theoretical perspective on variable practice was introduced by the system dynamic approach (Haken, 1970; Glansdorff and Prigogine, 1971). In contrast to previous learning approaches, the differentiation between errors and variations was replaced by the more neutral term of fluctuations derived from physics. One of the main characteristics of dissipative systems that have been investigated by the system dynamic approach is that living systems show fluctuations continuously and an increase of fluctuations before a phase transition. This observed increase of fluctuations constitutes the basis for a self-organizing process in a way that the system is exploring different modes during the increased fluctuations in order to find a new and more effective mode. Within the differential learning (DL) approach, fluctuations during the motor learning process are a fundamental basis for motor learning. In contrast, in repetition based motor learning movements are performed with a large number of repetitions without voluntary variations until a predefined ideal state of movement is reached. Based on these theoretical assumptions, the DL approach has been applied in the context of motor learning and extensively investigated by Schöllhorn and collaborates (Schöllhorn, 1999, 2000; Schöllhorn et al., 2006, 2009, 2010; Frank et al., 2008).
                    Jo Bowyer
                    Chartered Physiotherapist Registered Osteopath.
                    "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                    Comment


                    • Variable and Asymmetric Range of Enslaving: Fingers Can Act Independently over Small Range of Flexion

                      http://journals.plos.org/plosone/art...l.pone.0168636

                      Abstract

                      The variability in the numerous tasks in which we use our hands is very large. However, independent movement control of individual fingers is limited. To assess the extent of finger independency during full-range finger flexion including all finger joints, we studied enslaving (movement in non-instructed fingers) and range of independent finger movement through the whole finger flexion trajectory in single and multi-finger movement tasks. Thirteen young healthy subjects performed single- and multi-finger movement tasks under two conditions: active flexion through the full range of movement with all fingers free to move and active flexion while the non-instructed finger(s) were restrained. Finger kinematics were measured using inertial sensors (PowerGlove), to assess enslaving and range of independent finger movement. Although all fingers showed enslaving movement to some extent, highest enslaving was found in adjacent fingers. Enslaving effects in ring and little finger were increased with movement of additional, non-adjacent fingers. The middle finger was the only finger affected by restriction in movement of non-instructed fingers. Each finger showed a range of independent movement before the non-instructed fingers started to move, which was largest for the index finger. The start of enslaving was asymmetrical for adjacent fingers. Little finger enslaving movement was affected by multi-finger movement. We conclude that no finger can move independently through the full range of finger flexion, although some degree of full independence is present for smaller movements. This range of independent movement is asymmetric and variable between fingers and between subjects. The presented results provide insight into the role of finger independency for different types of tasks and populations.
                      Jo Bowyer
                      Chartered Physiotherapist Registered Osteopath.
                      "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                      Comment


                      • Is Implicit Motor Learning Preserved after Stroke? A Systematic Review with Meta-Analysis

                        http://journals.plos.org/plosone/art...l.pone.0166376

                        Abstract

                        Many stroke patients experience difficulty with performing dual-tasks. A promising intervention to target this issue is implicit motor learning, as it should enhance patients’ automaticity of movement. Yet, although it is often thought that implicit motor learning is preserved post-stroke, evidence for this claim has not been systematically analysed yet. Therefore, we systematically reviewed whether implicit motor learning is preserved post-stroke, and whether patients benefit more from implicit than from explicit motor learning. We comprehensively searched conventional (MEDLINE, Cochrane, Embase, PEDro, PsycINFO) and grey literature databases (BIOSIS, Web of Science, OpenGrey, British Library, trial registries) for relevant reports. Two independent reviewers screened reports, extracted data, and performed a risk of bias assessment. Overall, we included 20 out of the 2177 identified reports that allow for a succinct evaluation of implicit motor learning. Of these, only 1 study investigated learning on a relatively complex, whole-body (balance board) task. All 19 other studies concerned variants of the serial-reaction time paradigm, with most of these focusing on learning with the unaffected hand (N = 13) rather than the affected hand or both hands (both: N = 4). Four of the 20 studies compared explicit and implicit motor learning post-stroke. Meta-analyses suggest that patients with stroke can learn implicitly with their unaffected side (mean difference (MD) = 69 ms, 95% CI[45.1, 92.9], p < .00001), but not with their affected side (standardized MD = -.11, 95% CI[-.45, .25], p = .56). Finally, implicit motor learning seemed equally effective as explicit motor learning post-stroke (SMD = -.54, 95% CI[-1.37, .29], p = .20). However, overall, the high risk of bias, small samples, and limited clinical relevance of most studies make it impossible to draw reliable conclusions regarding the effect of implicit motor learning strategies post-stroke. High quality studies with larger samples are warranted to test implicit motor learning in clinically relevant contexts.
                        Jo Bowyer
                        Chartered Physiotherapist Registered Osteopath.
                        "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                        Comment


                        • It Pays to Go Off-Track: Practicing with Error-Augmenting Haptic Feedback Facilitates Learning of a Curve-Tracing Task

                          http://journal.frontiersin.org/artic...016.02010/full

                          Researchers in the domain of haptic training are now entering the long-standing debate regarding whether or not it is best to learn a skill by experiencing errors. Haptic training paradigms provide fertile ground for exploring how various theories about feedback, errors and physical guidance intersect during motor learning. Our objective was to determine how error minimizing, error augmenting and no haptic feedback while learning a self-paced curve-tracing task impact performance on delayed (1 day) retention and transfer tests, which indicate learning. We assessed performance using movement time and tracing error to calculate a measure of overall performance – the speed accuracy cost function. Our results showed that despite exhibiting the worst performance during skill acquisition, the error augmentation group had significantly better accuracy (but not overall performance) than the error minimization group on delayed retention and transfer tests. The control group’s performance fell between that of the two experimental groups but was not significantly different from either on the delayed retention test. We propose that the nature of the task (requiring online feedback to guide performance) coupled with the error augmentation group’s frequent off-target experience and rich experience of error-correction promoted information processing related to error-detection and error-correction that are essential for motor learning.
                          Jo Bowyer
                          Chartered Physiotherapist Registered Osteopath.
                          "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                          Comment


                          • Enhancing Nervous System Recovery through Neurobiologics, Neural Interface Training, and Neurorehabilitation

                            http://journal.frontiersin.org/artic...016.00584/full

                            After an initial period of recovery, human neurological injury has long been thought to be static. In order to improve quality of life for those suffering from stroke, spinal cord injury, or traumatic brain injury, researchers have been working to restore the nervous system and reduce neurological deficits through a number of mechanisms. For example, neurobiologists have been identifying and manipulating components of the intra- and extracellular milieu to alter the regenerative potential of neurons, neuro-engineers have been producing brain-machine and neural interfaces that circumvent lesions to restore functionality, and neurorehabilitation experts have been developing new ways to revitalize the nervous system even in chronic disease. While each of these areas holds promise, their individual paths to clinical relevance remain difficult. Nonetheless, these methods are now able to synergistically enhance recovery of native motor function to levels which were previously believed to be impossible. Furthermore, such recovery can even persist after training, and for the first time there is evidence of functional axonal regrowth and rewiring in the central nervous system of animal models. To attain this type of regeneration, rehabilitation paradigms that pair cortically-based intent with activation of affected circuits and positive neurofeedback appear to be required—a phenomenon which raises new and far reaching questions about the underlying relationship between conscious action and neural repair. For this reason, we argue that multi-modal therapy will be necessary to facilitate a truly robust recovery, and that the success of investigational microscopic techniques may depend on their integration into macroscopic frameworks that include task-based neurorehabilitation. We further identify critical components of future neural repair strategies and explore the most updated knowledge, progress, and challenges in the fields of cellular neuronal repair, neural interfacing, and neurorehabilitation, all with the goal of better understanding neurological injury and how to improve recovery.


                            Neurofeedback as a form of cognitive rehabilitation therapy following stroke: A systematic review

                            http://journals.plos.org/plosone/art...l.pone.0177290

                            Abstract

                            Neurofeedback therapy (NFT) has been used within a number of populations however it has not been applied or thoroughly examined as a form of cognitive rehabilitation within a stroke population. Objectives for this systematic review included: i) identifying how NFT is utilized to treat cognitive deficits following stroke, ii) examining the strength and quality of evidence to support the use of NFT as a form of cognitive rehabilitation therapy (CRT) and iii) providing recommendations for future investigations. Searches were conducted using OVID (Medline, Health Star, Embase + Embase Classic) and PubMed databases. Additional searches were completed using the Cochrane Reviews library database, Google Scholar, the University of Toronto online library catalogue, ClinicalTrials.gov website and select journals. Searches were completed Feb/March 2015 and updated in June/July/Aug 2015. Eight studies were eligible for inclusion in this review. Studies were eligible for inclusion if they: i) were specific to a stroke population, ii) delivered CRT via a NFT protocol, iii) included participants who were affected by a cognitive deficit(s) following stroke (i.e. memory loss, loss of executive function, speech impairment etc.). NFT protocols were highly specific and varied within each study. The majority of studies identified improvements in participant cognitive deficits following the initiation of therapy. Reviewers assessed study quality using the Downs and Black Checklist for Measuring Study Quality tool; limited study quality and strength of evidence restricted generalizability of conclusions regarding the use of this therapy to the greater stroke population. Progression in this field requires further inquiry to strengthen methodology quality and study design. Future investigations should aim to standardize NFT protocols in an effort to understand the dose-response relationship between NFT and improvements in functional outcome. Future investigations should also place a large emphasis on long-term participant follow-up.
                            17/05/2017
                            Last edited by Jo Bowyer; 17-05-2017, 04:13 PM.
                            Jo Bowyer
                            Chartered Physiotherapist Registered Osteopath.
                            "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                            Comment


                            • Joint Action: Mental Representations, Shared Information and General Mechanisms for Coordinating with Others

                              http://journal.frontiersin.org/artic...016.02039/full

                              In joint action, multiple people coordinate their actions to perform a task together. This often requires precise temporal and spatial coordination. How do co-actors achieve this? How do they coordinate their actions toward a shared task goal? Here, we provide an overview of the mental representations involved in joint action, discuss how co-actors share sensorimotor information and what general mechanisms support coordination with others. By deliberately extending the review to aspects such as the cultural context in which a joint action takes place, we pay tribute to the complex and variable nature of this social phenomenon.
                              Jo Bowyer
                              Chartered Physiotherapist Registered Osteopath.
                              "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                              Comment


                              • Causal Inference in Multisensory Heading Estimation

                                http://journals.plos.org/plosone/art...l.pone.0169676

                                Abstract

                                A large body of research shows that the Central Nervous System (CNS) integrates multisensory information. However, this strategy should only apply to multisensory signals that have a common cause; independent signals should be segregated. Causal Inference (CI) models account for this notion. Surprisingly, previous findings suggested that visual and inertial cues on heading of self-motion are integrated regardless of discrepancy. We hypothesized that CI does occur, but that characteristics of the motion profiles affect multisensory processing. Participants estimated heading of visual-inertial motion stimuli with several different motion profiles and a range of intersensory discrepancies. The results support the hypothesis that judgments of signal causality are included in the heading estimation process. Moreover, the data suggest a decreasing tolerance for discrepancies and an increasing reliance on visual cues for longer duration motions.
                                Jo Bowyer
                                Chartered Physiotherapist Registered Osteopath.
                                "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                                Comment

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