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  • The Motor Subsystem as a Predictor of Success in Young Football Talents: A Person-Oriented Study

    http://journals.plos.org/plosone/art...l.pone.0161049

    Introduction

    In order to select talents in football, it is essential to determine the players’ potential performance [1]. As it is difficult to assess their complex performance in the game objectively, one often resorts to fitness and technical tests in practice [2], since these are generally regarded to provide a high degree of objectivity and reliability [3, 4]. In terms of their validity, such tests ought to be able to distinguish between players displaying different levels of proficiency (concurrent validity), which they are generally considered to do [5]. However, when diagnosing talent, the difference in performance that will occur in the future—ideally when reaching the age of a competitive athlete—is of particularly great interest. The tests should therefore also be able to discriminate between players with different levels of potential (predictive validity). The question whether the fitness and technical tests currently used are able to meet these requirements has so far remained largely unanswered [2].

    In football, top performance requires a combination of excellent fitness skills and the greatest possible technical precision. The fitness skills that are particularly important include speed [6] (starting speed, speed of reaction, speed persistence, agility) and (intermittent) endurance [7]. Among the technical skills, particularly dribbling, passing, and ball handling appear to contribute substantially to explaining performance [1]. Against this background, it immediately becomes clear that a talent diagnosis that is based on the results of individual motor test will be inadequate. If only individual test results and their connection to sports performance are investigated, then the interactions between different characteristics, and the possibility of their compensating for each other, will not be taken into account [8]. On top of this, it does not seem plausible that individual variables should be able to predict a complex developmental process. Corresponding evidence is also found in developmental psychological research (as already noted by Wohlwill, [9]).

    In most cases, empirical studies and practical talent selection procedures have aggregated several variables or test outcomes in order to obtain as comprehensive a picture of the individual player as possible [10]. However, the question that arises here is how this aggregation should be done. This is the starting point for the current paper. So far, empirical studies aiming to assess the quality of the individual variables or test performance scores have developed models and tested theses using methods based on the General Linear Model (GLM) [11, 12]. Although GLM allows us to determine the variance attributable to individual variables, two problems still remain unresolved.

    Firstly, such procedures generally assume a linear relationship between independent and dependent variable, an assumption that often turns out to be questionable [13]. When looking at the motor test results, for example, it is necessary to critically question whether the performance in endurance tests is linearly related to a player’s performance on the pitch. Reilly et al. [10] have been able to demonstrate relatively large differences in the endurance of top football players. From a methodological point of view, other relationships could also be modelled, for example curvilinear models. However, in most cases, the nature of the relationship is not adequately explained on a theoretical level, and it may often even be doubtful whether the requirement of continuity is fulfilled. In fact, one should not rule out a priori the possibility of having step functions and thus discontinuous relationships.

    Secondly, a further assumption frequently made is that the same relationships apply to all individuals. However, it seems more plausible that the relationship between a certain characteristic and the criterion (of potential performance as a player) can only be assessed once the intra-individual degrees of expression of the other characteristics have been taken into account. To do justice to such an intra-individual perspective, it is necessary to resort to alternative concepts and methods.

    Since the fundamental questions of talent research are always related to processes in human development, it seems reasonable to base them on developmental scientific concepts. Modern developmental science takes a dynamic interactionist perspective (for an overview, cf. [14; 15]; in sports science: [16]). Magnusson and Cairns [17] in addition assume a holistic perspective of human development, which leads to a person-oriented approach [18]. This holistic approach is able to describe the development of an individual comprehensively, i.e. in the case of talent promotion, the entire process of developing from a promising young talent to a top athlete. The developing individual and his or her environment are viewed as a system, which can be divided up into various operationalisable subsystems. The interacting variables of a (sub-)system are called operating factors [19]. As the person-oriented approach does not assume linear relationships, it has to dispense with methods based on the GLM. For an overview and comparison of the variable- vs. person-oriented approach, cf. Bergman and Andersson [20].

    More recently, talent research has favoured multidimensional approaches [1, 21, 22] which adopt a perspective that focuses on the development process of the talent [23, 24]. The person-oriented approach considers both, a multidimensional as well as a developmental perspective in theoretical and methodological respects. So far, it has been successfully applied in sports talent research within the subsystems Training [25] and Motivation [26], with promising results. The idea therefore arises naturally to apply the person-oriented approach to fitness and technical skills, too, to develop a better understanding of the intra-individual relationship between different test performance scores and ultimately success.
    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 Sense of Agency Is More Sensitive to Manipulations of Outcome than Movement-Related Feedback Irrespective of Sensory Modality

      http://journals.plos.org/plosone/art...l.pone.0161156

      Abstract

      The sense of agency describes the ability to experience oneself as the agent of one's own actions. Previous studies of the sense of agency manipulated the predicted sensory feedback related either to movement execution or to the movement’s outcome, for example by delaying the movement of a virtual hand or the onset of a tone that resulted from a button press. Such temporal sensorimotor discrepancies reduce the sense of agency. It remains unclear whether movement-related feedback is processed differently than outcome-related feedback in terms of agency experience, especially if these types of feedback differ with respect to sensory modality. We employed a mixed-reality setup, in which participants tracked their finger movements by means of a virtual hand. They performed a single tap, which elicited a sound. The temporal contingency between the participants’ finger movements and (i) the movement of the virtual hand or (ii) the expected auditory outcome was systematically varied. In a visual control experiment, the tap elicited a visual outcome. For each feedback type and participant, changes in the sense of agency were quantified using a forced-choice paradigm and the Method of Constant Stimuli. Participants were more sensitive to delays of outcome than to delays of movement execution. This effect was very similar for visual or auditory outcome delays. Our results indicate different contributions of movement- versus outcome-related sensory feedback to the sense of agency, irrespective of the modality of the outcome. We propose that this differential sensitivity reflects the behavioral importance of assessing authorship of the outcome of an action.
      Jo Bowyer
      Chartered Physiotherapist Registered Osteopath.
      "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

      Comment


      • Robot-Aided Mapping of Wrist Proprioceptive Acuity across a 3D Workspace

        http://journals.plos.org/plosone/art...l.pone.0161155

        Abstract

        Proprioceptive signals from peripheral mechanoreceptors form the basis for bodily perception and are known to be essential for motor control. However we still have an incomplete understanding of how proprioception differs between joints, whether it differs among the various degrees-of-freedom (DoFs) within a particular joint, and how such differences affect motor control and learning. We here introduce a robot-aided method to objectively measure proprioceptive function: specifically, we systematically mapped wrist proprioceptive acuity across the three DoFs of the wrist/hand complex with the aim to characterize the wrist position sense. Thirty healthy young adults performed an ipsilateral active joint position matching task with their dominant wrist using a haptic robotic exoskeleton. Our results indicate that the active wrist position sense acuity is anisotropic across the joint, with the abduction/adduction DoF having the highest acuity (the error of acuity for flexion/extension is 4.64 ± 0.24°; abduction/adduction: 3.68 ± 0.32°; supination/pronation: 5.15 ± 0.37°) and they also revealed that proprioceptive acuity decreases for smaller joint displacements. We believe this knowledge is imperative in a clinical scenario when assessing proprioceptive deficits and for understanding how such sensory deficits relate to observable motor impairments.
        May be of interest to those who need to get their hand to an optimum position in space/time to catch something or use a weapon, or those who have patients that do.

        I used to get fencers to bring their weapons in, but often found that I spent much more time dealing with shite footwork
        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 Sensorimotor System Can Sculpt Behaviorally Relevant Representations for Motor Learning

          http://eneuro.org/content/3/4/ENEURO...16.2016?cpetoc

          Abstract

          The coordinate system in which humans learn novel motor skills is controversial. The representation of sensorimotor skills has been extensively studied by examining generalization after learning perturbations specifically designed to be ambiguous as to their coordinate system. Recent studies have found that learning is not represented in any simple coordinate system and can potentially be accounted for by a mixed representation. Here, instead of probing generalization, which has led to conflicting results, we examine whether novel dynamics can be learned when explicitly and unambiguously presented in particular coordinate systems. Subjects performed center–out reaches to targets in the presence of a force field, while varying the orientation of their hand (i.e., the wrist angle) across trials. Different groups of subjects experienced force fields that were explicitly presented either in Cartesian coordinates (field independent of hand orientation), in object coordinates (field rotated with hand orientation), or in anti-object coordinates (field rotated counter to hand orientation). Subjects learned to represent the dynamics when presented in either Cartesian or object coordinates, learning these as well as an ambiguous force field. However, learning was slower for the object-based dynamics and substantially impaired for the anti-object presentation. Our results show that the motor system is able to tune its representation to at least two natural coordinate systems but is impaired when the representation of the task does not correspond to a behaviorally relevant coordinate system. Our results show that the motor system can sculpt its representation through experience to match those of natural tasks.
          via @SimonGandevia
          Last edited by Jo Bowyer; 24-08-2016, 02:55 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


          • Proactive modulation of long-interval intracortical inhibition during response inhibition

            http://jn.physiology.org/content/116...bstract?cpetoc

            Abstract

            Daily activities often require sudden cancellation of preplanned movement, termed response inhibition. When only a subcomponent of a whole response must be suppressed (required here on Partial trials), the ensuing component is markedly delayed. The neural mechanisms underlying partial response inhibition remain unclear. We hypothesized that Partial trials would be associated with nonselective corticomotor suppression and that GABAB receptor-mediated inhibition within primary motor cortex might be responsible for the nonselective corticomotor suppression contributing to Partial trial response delays. Sixteen right-handed participants performed a bimanual anticipatory response inhibition task while single- and paired-pulse transcranial magnetic stimulation was delivered to elicit motor evoked potentials in the left first dorsal interosseous muscle. Lift times, amplitude of motor evoked potentials, and long-interval intracortical inhibition were examined across the different trial types (Go, Stop-Left, Stop-Right, Stop-Both). Go trials produced a tight distribution of lift times around the target, whereas those during Partial trials (Stop-Left and Stop-Right) were substantially delayed. The modulation of motor evoked potential amplitude during Stop-Right trials reflected anticipation, suppression, and subsequent reinitiation of movement. Importantly, suppression was present across all Stop trial types, indicative of a “default” nonselective inhibitory process. Compared with blocks containing only Go trials, inhibition increased when Stop trials were introduced but did not differ between trial types. The amount of inhibition was positively correlated with lift times during Stop-Right trials. Tonic levels of inhibition appear to be proactively modulated by task context and influence the speed at which unimanual responses occur after a nonselective “brake” is applied.
            via @SimonGandevia
            Jo Bowyer
            Chartered Physiotherapist Registered Osteopath.
            "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

            Comment


            • Premotor and Motor Cortices Encode Reward

              http://journals.plos.org/plosone/art...l.pone.0160851

              Abstract

              Rewards associated with actions are critical for motivation and learning about the consequences of one’s actions on the world. The motor cortices are involved in planning and executing movements, but it is unclear whether they encode reward over and above limb kinematics and dynamics. Here, we report a categorical reward signal in dorsal premotor (PMd) and primary motor (M1) neurons that corresponds to an increase in firing rates when a trial was not rewarded regardless of whether or not a reward was expected. We show that this signal is unrelated to error magnitude, reward prediction error, or other task confounds such as reward consumption, return reach plan, or kinematic differences across rewarded and unrewarded trials. The availability of reward information in motor cortex is crucial for theories of reward-based learning and motivational influences on actions.
              Introduction

              How the brain learns based on action outcomes is a central question in neuroscience. Theories of motor learning have usually focused on rapid, error-based learning mediated by the cerebellum, and slower, reward-based learning mediated by the basal ganglia (for a review, see [1]). Different combinations of reward and sensory feedback result in different learning rates. For instance, positive and negative rewards influence motor learning differently [2, 3]. When reward is combined with sensory feedback, it can accelerate motor learning [4]. Reward is thus a fundamental aspect of learning [5, 6, 7, 8]. Various reward signals have been characterized in the midbrain, prefrontal and limbic cortices [9, 10, 11, 12, 13]. Yet, we do not know how neurons in the motor system obtain the reward information that could be useful for planning subsequent movements.

              The dorsal premotor cortex (PMd) and the primary motor cortex (M1) are known to be involved in planning and executing movements. We know this because movement goals (e.g., direction of upcoming movement), kinematics (e.g., position, velocity and acceleration) and dynamics (e.g. forces, torques, and muscle activity) are reflected in the firing rates of motor cortical neurons [14, 15, 16, 17, 18, 19, 20]. If movement plans need to be modified based on previous actions, then information about their outcomes must reach motor cortices. In many real world settings, task outcomes typically manifest in the form of reward.

              Recently, Marsh et al. [21] have shown a robust modulation of M1 activity by reward expectation both during movement and observation of movement. To further investigate the nature of this potential reward signal, we trained monkeys to reach to targets based on noisy spatial cues and rewarded them for correct reaches. We induced different reward expectation on a trial-by-trial basis and quantified the representation of reward in PMd and M1. We observed that ~28% of PMd neurons and ~12% of M1 neurons significantly modulated their firing rates following trials that were not rewarded. The effect could not be explained simply by kinematic variables such as velocity or acceleration, reward consumption behavior, or upcoming movement plans, nor by task variables that may bias successful task performance, such as the noise in the target cue, the reward history, or the precision of the reach. This effect might constitute an important piece in the larger puzzle of how motor plans are modified based on reward.
              Jo Bowyer
              Chartered Physiotherapist Registered Osteopath.
              "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

              Comment


              • Motor Skills and Exercise Capacity Are Associated with Objective Measures of Cognitive Functions and Academic Performance in Preadolescent Children

                http://journals.plos.org/plosone/art...l.pone.0161960

                Abstract

                Objective

                To investigate associations between motor skills, exercise capacity and cognitive functions, and evaluate how they correlate to academic performance in mathematics and reading comprehension using standardised, objective tests.

                Methods

                This cross-sectional study included 423 Danish children (age: 9.29±0.35 years, 209 girls). Fine and gross motor skills were evaluated in a visuomotor accuracy-tracking task, and a whole-body coordination task, respectively. Exercise capacity was estimated from the Yo-Yo intermittent recovery level 1 children's test (YYIR1C). Selected tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were used to assess different domains of cognitive functions, including sustained attention, spatial working memory, episodic and semantic memory, and processing speed. Linear mixed-effects models were used to investigate associations between these measures and the relationship with standard tests of academic performance in mathematics and reading comprehension.

                Results

                Both fine and gross motor skills were associated with better performance in all five tested cognitive domains (all P<0.001), whereas exercise capacity was only associated with better sustained attention (P<0.046) and spatial working memory (P<0.038). Fine and gross motor skills (all P<0.001), exercise capacity and cognitive functions such as working memory, episodic memory, sustained attention and processing speed were all associated with better performance in mathematics and reading comprehension.

                Conclusions

                The data demonstrate that fine and gross motor skills are positively correlated with several aspects of cognitive functions and with academic performance in both mathematics and reading comprehension. Moreover, exercise capacity was associated with academic performance and performance in some cognitive domains. Future interventions should investigate associations between changes in motor skills, exercise capacity, cognitive functions, and academic performance to elucidate the causality of these associations.
                Jo Bowyer
                Chartered Physiotherapist Registered Osteopath.
                "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                Comment


                • Analysis of Hand and Wrist Postural Synergies in Tolerance Grasping of Various Objects

                  http://journals.plos.org/plosone/art...l.pone.0161772

                  Abstract

                  Human can successfully grasp various objects in different acceptable relative positions between human hand and objects. This grasp functionality can be described as the grasp tolerance of human hand, which is a significant functionality of human grasp. To understand the motor control of human hand completely, an analysis of hand and wrist postural synergies in tolerance grasping of various objects is needed. Ten healthy right-handed subjects were asked to perform the tolerance grasping with right hand using 6 objects of different shapes, sizes and relative positions between human hand and objects. Subjects were wearing CyberGlove attaching motion tracker on right hand, allowing a measurement of the hand and wrist postures. Correlation analysis of joints and inter-joint/inter-finger modules were carried on to explore the coordination between joints or modules. As the correlation between hand and wrist module is not obvious in tolerance grasping, individual analysis of wrist synergies would be more practical. In this case, postural synergies of hand and wrist were then presented separately through principal component analysis (PCA), expressed through the principal component (PC) information transmitted ratio, PC elements distribution and reconstructed angle error of joints. Results on correlation comparison of different module movements can be well explained by the influence factors of the joint movement correlation. Moreover, correlation analysis of joints and modules showed the wrist module had the lowest correlation among all inter-finger and inter-joint modules. Hand and wrist postures were both sufficient to be described by a few principal components. In terms of the PC elements distribution of hand postures, compared with previous investigations, there was a greater proportion of movement in the thumb joints especially the interphalangeal (IP) and opposition rotation (ROT) joint. The research could serve to a complete understanding of hand grasp, and the design, control of the anthropomorphic hand and wrist.
                  I am particularly interested in post stroke upper limb and hand function, not only with regards what might eventually be retrieved, but also because of the ongoing effects of the rehab process on the body as a functional unit. Some patients elect to carry the affected arm as a passenger, because they feel daunted by the prospect of the work involved.



                  Exercise for hand osteoarthritis.......from Cochran
                  http://www.cochrane.org/CD010388/MUS...osteoarthritis

                  Low-quality evidence from five trials (381 participants) indicated that exercise reduced hand pain (standardised mean difference (SMD) -0.27, 95% confidence interval (CI) -0.47 to -0.07) post intervention. The absolute reduction in pain for the exercise group, compared with the control group, was 5% (1% to 9%) on a 0 to 10 point scale. Pain was estimated to be 3.9 points on this scale (0 = no pain) in the control group, and exercise reduced pain by 0.5 points (95% CI 0.1 to 0.9; number needed to treat for an additional beneficial outcome (NNTB) 9).
                  Yup....far better to take a neuro/functional approach.

                  Update 10/04/2017
                  Last edited by Jo Bowyer; 10-04-2017, 10:09 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


                  • Explicit Agency in Patients with Cervical Dystonia: Altered Recognition of Temporal Discrepancies between Motor Actions and Their Feedback

                    http://journals.plos.org/plosone/art...l.pone.0162191

                    Abstract

                    Background

                    Abnormalities in the cognitive processing of movement have been demonstrated in patients with dystonia. The sense of agency, which is the experience of initiating and controlling one’s own actions, has never before been studied in these patients.

                    Objectives

                    We investigated whether the sense of agency is altered in patients with cervical dystonia.

                    Methods

                    We used an explicit metacognitive agency task in which participants had to catch targets with a cursor by moving a computer’s mouse. The task included several conditions in which the control over the cursor could be disrupted by adding a spatial or a temporal discrepancy between the mouse and the cursor’s movements. Participants had to acknowledge these discrepancies and reflect them in metacognitive judgements of agency.

                    Results

                    Twenty cervical dystonia patients and 20 matched controls were included in the study. Despite performing equally well as the matched controls, cervical dystonia patients did not fully recognize alterations of agency when a temporal lag was added between their movement and the visual feedback. Moreover, they relied predominantly on their perceived performance to provide judgements of agency and less on their objective degree of controls. There was no correlation between agency scores and clinical severity of dystonia measured by the Toronto Western Spasmodic Torticollis Rating Scale.

                    Conclusion

                    We demonstrated an abnormal processing of agency in cervical dystonia patients, even for motor actions not affected by dystonia. The exact contribution of abnormal agency to dystonia pathophysiology remains to be clarified.


                    Editorial: Unmet Needs in Dystonia

                    http://journal.frontiersin.org/artic...017.00197/full

                    The common theme of this publication is lumping vs splitting. How many dystonia syndromes exist clinically, genetically, neurophysiologically, etc.?

                    The first chapter in this Research Topic, by Albanese, is a clinical and historical review ending with a proposal on the new diagnostic criteria for dystonia syndromes. The descriptions of dystonia from post-medieval ages till now are reported. This exercise accounts for innovative clinical observations and scholar thinking. The second chapter by Verbeek and Gasser reviews the genetic heterogeneity of dystonia syndromes. Whole-exome sequencing and genome-wide association studies have allowed the discovery of novel genes and risk factors for dystonia. How to combine clinical and genetic heterogeneity is a matter for future research.

                    The third chapter by Valls-Sole and Defazio is an update on blepharospasm. Phenomenology and electrophysiology are reviewed for this simple, yet complex, focal dystonia. A chapter by Contarino et al. reviews the complex management of cervical dystonia, the most common focal dystonia syndrome. In this area, we expect several innovations, including treatment of non-motor features and functional neurosurgery. Evidence-based recommendations for the treatment of cervical dystonia with botulinum toxin are reviewed in the fifth chapter. Cervical dystonia is an area where we expect most innovation in management with botulinum neurotoxins. Injection of deep cervical muscles, usage of ultrasound, and EMG combined are rewriting current clinical practice. The next chapter by Lin and Nardocci reviews the complex issue of childhood dystonia that is often combined with other movement disorders or neurodevelopmental issues. Finally, the needs and requirements of modern biobanks, an issue extensively discussed within the COST Action, are reviewed by Lohmann et al.
                    Update 09/05/2017
                    Last edited by Jo Bowyer; 09-05-2017, 06:44 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


                    • Physical Activity Is Associated with Reduced Implicit Learning but Enhanced Relational Memory and Executive Functioning in Young Adults

                      http://journals.plos.org/plosone/art...l.pone.0162100

                      Abstract

                      Accumulating evidence suggests that physical activity improves explicit memory and executive cognitive functioning at the extreme ends of the lifespan (i.e., in older adults and children). However, it is unknown whether these associations hold for younger adults who are considered to be in their cognitive prime, or for implicit cognitive functions that do not depend on motor sequencing. Here we report the results of a study in which we examine the relationship between objectively measured physical activity and (1) explicit relational memory, (2) executive control, and (3) implicit probabilistic sequence learning in a sample of healthy, college-aged adults. The main finding was that physical activity was positively associated with explicit relational memory and executive control (replicating previous research), but negatively associated with implicit learning, particularly in females. These results raise the intriguing possibility that physical activity upregulates some cognitive processes, but downregulates others. Possible implications of this pattern of results for physical health and health habits are discussed.
                      Introduction

                      It is widely accepted that physical activity improves and maintains physical health, but there is also evidence that it is associated with improved cognitive functioning. To date, most of the evidence for the salutary effects of physical activity on cognition comes from the field of cognitive aging. For example, more physically active older adults outperform their less physically active peers on a variety of cognitive tasks [1,2], and a greater amount of physical activity is associated with a lower risk of experiencing cognitive impairment over a 1–12 year period [3]. Randomized controlled trials of exercise also report improvements in cognitive functioning in older adults following aerobic exercise training compared to active control conditions (e.g., [4,5,6]). Meta-analyses of training studies have revealed that cognitive improvements following exercise training are particularly pronounced in the domains of memory and executive functioning [7,8]. Thus, there is evidence that physical activity improves cognitive functioning, and that there may be some specificity, such that it benefits some cognitive processes more than others (but see [9] for evidence to the contrary). Here, we expand the existing literature by examining, for the first time in the same study, the relationship between physical activity and explicit, as well as implicit cognitive functioning (specifically implicit probabilistic sequence learning). Further, we will do so in a sample of healthy younger adults rather than in the older adult samples typically tested in studies of physical activity and cognition.

                      The idea that physical activity may be particularly beneficial for memory and executive functioning in humans is perhaps not surprising considering what has long been known about the neural effects of exercise from animal models. Specifically, aerobic exercise increases neurogenesis in the hippocampus, a region central for learning and memory (e.g., [10]). For example, rodents given access to running wheels show enhanced proliferation and survival of newborn neurons in the dentate gyrus, a hippocampal subregion, as well as superior performance on hippocampal-dependent cognitive tasks (e.g., spatial memory, novel object recognition) compared to sedentary rodents (for review see [11]). In addition, exercise increases the proliferation of new capillary beds, increases expression of neurotrophic factors and neurotransmitters, and influences inflammatory cytokines (for review see [11]). Studies of aerobic exercise in rodents have therefore highlighted several mechanisms by which aerobic activity affects cognitive performance, suggesting that the effects of physical activity in humans are mediated by enhanced neural (particularly hippocampal) functioning. One important caveat of using animal models, however, is that the results cannot always be directly extrapolated to humans.

                      Neuroimaging studies of physical activity in humans complement the rodent literature. In older humans, a 12-month randomized controlled trial of aerobic exercise increased hippocampal volume, and these changes in hippocampal volume were associated with changes in spatial memory performance [4]. Others have since replicated the effects of exercise on hippocampal volume and cognitive performance [12,13] and have shown that exercise also affects the structure and functioning of other brain regions, such as the prefrontal and anterior cingulate cortices, regions supporting executive cognitive functions [14–16]. In addition to inducing structural brain changes, exercise improves the strength of functional communication between the hippocampus and prefrontal cortex, as well as amongst regions within large-scale brain networks [17,18]. The emerging evidence from fMRI studies of exercise in humans thus builds upon the animal work in that it suggests that physical activity not only impacts individual brain regions associated with specific cognitive functions—e.g., the hippocampus and prefrontal cortex—but that it may also have more global influences on brain communication and efficiency.

                      Despite the wealth of evidence that physical activity promotes both cognitive and brain health, there are still many open questions. For example, although studies of physical activity have included a variety of cognitive tasks measuring explicit cognitive functions (i.e., those that are goal-directed and subsequently verbalizable), few have included tasks assessing implicit functions (i.e., those that occur without awareness or intent and are not subsequently verbalizable). The primary goal of the present study was to examine whether the relationship between physical activity and cognition also extends to an implicit function, implicit probabilistic sequence learning (IL). IL is a cognitive process that involves acquiring probabilistic regularities from sequences of events. This type of learning is thought to underlie important everyday functions, such as developing new languages, adapting to new social and built environments, and forming new behavioral repertoires [19].

                      To measure IL in the laboratory, here we use the Triplets Learning Task (TLT) [20]. The TLT measures implicit probabilistic sequence learning that occurs independently of motor sequencing. Importantly, the more perceptual form of IL measured by the TLT differs from motor-based IL (the type measured in traditional sequence learning paradigms) because it requires participants to extract subtle sequential regularities from the environment independently of the influences of motor fluency [21]. Thus, IL in the TLT does not involve learning a motor sequence, and is not confounded by individual (or group) differences in motor capacity. However, the TLT shares several key qualities with motor-based sequence learning tasks, such as the fact that learning is sequential and (in most cases) implicit. Thus, we use “IL” when referring to both variations of implicit sequence learning generally, and we will call on evidence from both the motor and perceptual IL literatures to frame and interpret the present results. However, given the differences outlined above, we will highlight when the tasks employed across studies differ in terms of their motor demands and later speculate on if/when this matters in terms of the effects observed.

                      IL (both motor and perceptual) is thought to proceed in several stages, which can broadly be divided into the training or “acquisition” phase, and the offline or “consolidation” phase [22]. We focus on the acquisition phase in the present study. Within the contemporary IL literature, the acquisition phase is often further subdivided into an initial, early learning phase in which associations are being rapidly formed, and a later learning phase in which the probabilistic associations become more automatized [20,23,24]. This distinction may be critical as there is growing evidence that different neural systems may underlie the different phases of acquisition (e.g., [23]).

                      There is reason to expect that IL might be sensitive to individual differences in physical activity. This is because functional magnetic imaging (fMRI) studies have demonstrated that, in initial phases of both perceptual and motor-based IL, participants recruit the caudate nucleus, as well as the hippocampus, a region that, as mentioned above, is known to be particularly sensitive to exercise training [23,25–29]. In addition, the integrity of white matter tracts connecting the hippocampus and caudate to the dorsolateral prefrontal cortex (DLPFC) is associated with better motor-based IL performance in the early and late phases of training, respectively [30]. Thus, both the hippocampus and DLPFC, regions known to disproportionately benefit from physical activity, are also linked to IL aptitude. Given that various types of IL rely on overlapping neural substrates to those affected by physical activity, we could predict a positive association between physical activity and IL in the TLT, in particular in initial stages of learning when the hippocampus may be most involved.

                      The prediction above, however, is complicated by findings suggesting that IL is impaired by the sustained engagement of the prefrontal cortex and hippocampus. For example, IL on a motor-sequence learning task improves following hypnosis [31], a procedure thought to disinhibit automatic behaviors by reducing the top-down modulatory influence of the prefrontal cortex on other brain regions. IL on a perceptual sequence learning task is negatively associated with dispositional mindfulness, a trait-like quality hypothesized to increase prefrontal and hippocampal functioning and to thus promote top-down regulatory processes [32]. In addition, better IL is associated with decreasing hippocampal and increasing striatal activation over the course of both motor and perceptual IL tasks, suggesting that optimal hippocampal involvement in IL is comparatively short-lived to that of the striatum during the acquisition phase of IL, even across tasks of differing motor demands [23,26]. This later finding suggests that optimal IL performance may be related to an earlier switch from hippocampal to striatal control during IL acquisition. That is, there is evidence that the hippocampal and striatal systems may compete for control of behavior during IL tasks, particularly initially in learning when the systems are observed to be most coactive (e.g., [23,26,28]).

                      Further, there is evidence from addiction studies in both animals and humans demonstrating that exercise reduces habitual (i.e., drug-seeking) behaviors, lowers the risk of addictive relapse, and even leads to a reduction in individuals’ propensity to develop new habitual behaviors (for review see [33]). Since better IL has been posited to be an indicator of inter-individual variability in one’s propensity for habit formation [34,35], it is possible that IL may not always be advantageous and that physical activity may be linked to worse IL due to its enhancement of neural systems supporting more deliberate, and explicit, learning strategies. Together, these findings suggest that physical activity may be negatively related to IL performance.

                      An additional open question stems from the fact that, to date, the majority of studies examining the link between physical activity and cognitive functioning have focused on older adults. It is therefore unclear to what extent PA relates to cognitive functioning—implicit or explicit—in other adult age groups, especially younger adults. Indeed, there are known moderators of the physical activity and cognition relationship (e.g., age, gender, dosage), such that the effects of physical activity on cognition are stronger for certain subgroups (e.g., older adults) than for others (e.g. [7]). Young adults are a generally healthy/high-functioning group that might thus be hypothesized to be less sensitive to the effects of physical activity. However, young adults, on average, have a remarkably sedentary lifestyle in contemporary society [36,37]. Thus, even though they may be in their cognitive “prime”, there is a wide range of inter-individual variability in physical activity engagement within this age group that might have important implications for understanding individual differences in cognitive performance and overall health. Therefore, a secondary aim of the present study was to test for relationships between physical activity and cognitive functioning in an adult sample much younger than that typically examined.

                      In the present study, fifty young adults underwent objective physical activity monitoring. They then completed a measure of IL, the Triplets Learning Task, as well as measures of relational memory and executive cognitive functioning (an explicit relational memory task and a word-color Stroop task). In regards to our primary aim, we predicted that IL in the TLT would be related to physical activity levels, with the directionality of this association possibly dependent on the session of learning. In regards to our secondary aim, we predicted that physical activity would be positively associated with relational memory and executive functioning, replicating the findings from older adults in a younger adult age group.
                      Jo Bowyer
                      Chartered Physiotherapist Registered Osteopath.
                      "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                      Comment


                      • Muscle Relaxation of the Foot Reduces Corticospinal Excitability of Hand Muscles and Enhances Intracortical Inhibition

                        http://journal.frontiersin.org/artic...016.00218/full

                        Introduction
                        In daily life and sports, many occasions require the simultaneous use of multiple limbs. In some cases, activity in a muscle of one limb interferes with the activity of other muscles in other limbs. For example, when cyclic movements of the ipsilateral upper and lower limbs are executed, movement in one of these limbs is affected by movement of the other (Baldissera et al., 1982; Kelso and Jeka, 1992; Carson et al., 1995; Muraoka et al., 2013). Studies on the underlying neural mechanisms report that muscle contraction in one limb induces an increase in the amplitude of the H-reflex as well as in the excitability of the primary motor cortex (M1) related to the other limb (Jendrássik, 1883; Delwaide and Toulouse, 1981; Hortobágyi et al., 2003; Tazoe et al., 2009; Muraoka et al., 2015). Such interlimb interactions are described as “remote effects”. During cyclic movement of the foot, corticospinal excitability of the resting extensor carpi radialis (ECR) with pronated forearm is higher during dorsiflexion than during plantar flexion. On the other hand, corticospinal excitability of the flexor carpi radialis (FCR) is higher during plantarflexion than during dorsiflexion (Baldissera et al., 2002; Byblow et al., 2007).

                        It is important to be aware that in our daily activities both muscle contraction and relaxation are critical. The necessity for rapid interaction between these two states has been noted to be particularly important for fast paced activities involved in sports (Sakurai and Ohtsuki, 2000) and music performance (Fujii et al., 2009; Yoshie et al., 2009). Furthermore, lack of appropriate muscle relaxation is a typical symptom for patients exhibiting Parkinsonism (Gauggel et al., 2004), dystonia (Yazawa et al., 1999) or stroke (Kamper et al., 2003). We have recently shown that muscle relaxation can influence on remote muscle activities. Muscle relaxation of the foot suppressed electromyographic activity (EMG) of ipsilateral hand muscles that were to simultaneously contract (Kato et al., 2014, 2015). This indicates that muscle relaxation can temporarily produce an inhibitory effect on muscle activity in a different limb. However, the neural mechanisms of inter-limb interactions involved with muscle relaxation are poorly understood.
                        Jo Bowyer
                        Chartered Physiotherapist Registered Osteopath.
                        "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                        Comment


                        • Distinct roles of visual, parietal, and frontal motor cortices in memory-guided sensorimotor decisions

                          https://elifesciences.org/content/5/e13764

                          Abstract
                          Mapping specific sensory features to future motor actions is a crucial capability of mammalian nervous systems. We investigated the role of visual (V1), posterior parietal (PPC), and frontal motor (fMC) cortices for sensorimotor mapping in mice during performance of a memory-guided visual discrimination task. Large-scale calcium imaging revealed that V1, PPC, and fMC neurons exhibited heterogeneous responses spanning all task epochs (stimulus, delay, response). Population analyses demonstrated unique encoding of stimulus identity and behavioral choice information across regions, with V1 encoding stimulus, fMC encoding choice even early in the trial, and PPC multiplexing the two variables. Optogenetic inhibition during behavior revealed that all regions were necessary during the stimulus epoch, but only fMC was required during the delay and response epochs. Stimulus identity can thus be rapidly transformed into behavioral choice, requiring V1, PPC, and fMC during the transformation period, but only fMC for maintaining the choice in memory prior to execution.
                          Jo Bowyer
                          Chartered Physiotherapist Registered Osteopath.
                          "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                          Comment


                          • Bilateral coordination of walking and freezing of gait in Parkinson’s disease

                            http://onlinelibrary.wiley.com/doi/1...8.06167.x/full

                            Introduction

                            Freezing of gait (FOG) is a debilitating gait impairment in patients with Parkinson's disease (PD), prevalent in about 50% of the patients with advanced disease (Fahn, 1995; Giladi, 2001). The origins of FOG are largely unknown (reviews: Giladi et al., 2001; Bloem et al., 2004). Several studies that have examined the physiological mechanisms associated with FOG in PD suggested that abnormalities of the spatiotemporal characteristics (Nieuwboer et al., 2001; Iansek et al., 2006) and of the sequencing of gait (Iansek et al., 2006) may lead to the onset of freezing. Dysrhythmic (Hausdorff et al., 2003) and asymmetric (Plotnik et al., 2005) gait were also associated with FOG in PD.

                            We hypothesized that impaired bilateral coordination of gait may be associated with FOG. A clinical observation that leads to this hypothesis is that FOG most frequently occurs at turns or during the initiation of walking (Schaafsma et al., 2003). In contrast to forward walking where both legs basically perform similar motor patterns, during turns the pivot leg carries out a different motor pattern from the swing leg because each of the legs covers different distances and turn with different radii. At gait initiation, the difference between the motor activity of each leg is even more pronounced as one leg takes a step while the pivot leg provides support. In both conditions, due to the marked difference in the actual movement of each leg, there is a need for a high degree of coordination. Therefore, impairments in the bilateral coordination of gait, if they exist, might lead to ineffective execution of locomotion and to the appearance of FOG, particularly during those two locomotion tasks.

                            The mechanisms underlying the coordination of bipedal human walking are not fully understood. The studies that quantitatively investigated bilateral coordination of locomotion in humans primarily employed paradigms involving non-natural conditions, e.g. bicycle pedaling (Abe et al., 2003) or walking on a split-belt treadmill (for a review, see Dietz, 2002). An incomplete understanding is notable in patients with gait pathologies, such as those seen in PD. While studies have observed characteristics suggestive of impaired bilateral coordination of locomotion in PD (Dietz et al., 1995; Abe et al., 2003), most studies have not examined walking.
                            Jo Bowyer
                            Chartered Physiotherapist Registered Osteopath.
                            "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                            Comment


                            • &quot;It don't mean a thing if it ain't got that swing&quot;– an Alternative Concept for Understanding the Evolution of Dance and Music in Human Beings

                              http://journal.frontiersin.org/artic...00485/abstract

                              The functions of dance and music in human evolution are a mystery. Current research on the evolution of music has mainly focused on its melodic attribute which would have evolved alongside proto-language. Instead, we propose an alternative conceptual framework which focuses on the co-evolution of rhythm and dance (R&D) as intertwined aspects of a multimodal phenomenon characterized by the unity of action and perception. Reviewing the current literature from this viewpoint we propose the hypothesis that R&D have co-evolved long before other musical attributes and (proto)-language. Our view is supported by increasing experimental evidence particularly in infants and children: beat is perceived and anticipated already by newborns and rhythm perception depends on body movement. Infants and toddlers spontaneously move to a rhythm irrespective of their cultural background. If this behavior is universal, R&D must have an essential function in human evolution. Conceivable evolutionary functions of R&D include sexual attraction, transmission of mating signals, synchronization of many individuals, social bonding, appeasement of hostile individuals, pre- and extra-verbal communication, improvement of body coordination, as well as pain killing, anti-depressive, and anti-boredom functions. The impulse to dance may have been prepared by the susceptibility of infants to be soothed by rocking. Dance enables embodied individual and collective memorizing; in many cultures R&D are used for entering trance, a base for shamanism and early religions. Rhythm is necessary to codify human speech and dance encompasses gesture.
                              In future studies attention should be paid to which attribute of music is focused and that the close mutual relation between R&D is taken into account. The possible evolutionary functions of dance deserve more attention.
                              Jo Bowyer
                              Chartered Physiotherapist Registered Osteopath.
                              "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

                              Comment


                              • Proprioception: The Sense Within By Uwe Proske and Simon Gandevia

                                http://www.the-scientist.com/?articl...-Sense-Within/

                                Knowing where our bodies are in space is critical for the control of our movements and for our sense of self.
                                Often altered in complex pain patients. I set proprioceptive homework from the off.


                                Skin at the back of the ankle contributes to awareness of ankle position

                                https://motorimpairment.neura.edu.au...nkle-position/

                                Update 27/07/2017
                                Last edited by Jo Bowyer; 27-07-2017, 01:52 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

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