Multiple cortical areas of the human brain motor system interact coherently in the low frequency range (< 0.1 Hz), even in the absence of explicit tasks. Following stroke, cortical interactions are functionally disturbed. How these interactions are affected and how the functional organization is regained from rehabilitative treatments as people begin to recover motor behaviors has not been systematically studied. We recorded the intrinsic functional magnetic resonance imaging (fMRI) signals from 30 participants: 17 young healthy controls and (...) 13 aged stroke survivors. Stroke participants underwent mental practice (MP) or both mental practice and physical therapy (MP + PT) within 14-51 days following stroke. We investigated the network activity of five core areas in the motor-execution network, consisting of the left primary motor area (LM1), the right primary motor area (RM1), the left pre-motor cortex (LPMC), the right pre-motor cortex (RPMC) and the supplementary motor area (SMA). We discovered that (i) the network activity dominated in the frequency range 0.06 Hz – 0.08 Hz for all the regions, and for both able-bodied and stroke participants (ii) the causal information flow between the regions: LM1 and SMA, RPMC and SMA, RPMC and LM1, SMA and RM1, SMA and LPMC, was reduced significantly for stroke survivors (iii) the flow did not increase significantly after MP alone and (iv) the flow among the regions during MP+PT increased significantly. We also found that sensation and motor scores were significantly higher and correlated with directed functional connectivity measures when the stroke-survivors underwent MP+PT but not MP alone. The findings provide evidence that a combination of mental practice and physical therapy can be an effective means of treatment for stroke survivors to recover or regain the strength of motor behaviors, and that the spectra of causal information flow can be used as a reliable biomarker for evaluating rehabilitation in stroke survivors. (shrink)

Fractal structure is a ubiquitous property found in nature and biology, and has been observed in processes at different levels of organization, including rhythmic behavior and musical structure. A temporal process is characterized as fractal when serial long-term correlations and statistical self-similarity (scaling) are present. Previous studies of sensorimotor synchronization using isochronous (non-fractal) stimuli show that participants' errors exhibit persistent structure (positive long-term correlations), while their inter-tap intervals (ITIs) exhibit anti-persistent structure (negative long-term correlations). Auditory-motor synchronization has not (...) been investigated with anti-persistent stimuli. In the current study, we systematically investigated whether the fractal structure of auditory rhythms was reflected in the responses of participants who were asked to coordinate their taps with each event. We asked musicians and non-musicians to tap with 12 different rhythms that ranged from anti-persistent to persistent. The scaling exponents of the ITIs were strongly correlated with the scaling exponents of the stimuli, showing that the long-term structure of the participants' taps scaled with the long-term structure of the stimuli. Surprisingly, the performance of the musicians was not significantly better than that of the non-musicians. Our results imply that humans are able to readily adapt (rather than simply react) to the overall statistical structure of temporally fluctuating stimuli, regardless of musical skill. (shrink)

The representational dynamics of the brain is a subsymbolic process, and it has to be conceived as an "agent-free" type of dynamical self-organization. However, in generating a coherent internal world-model, the brain decomposes target space in a certain way. In doing so, it defines an "ontology": to have an ontology is to interpret a world. In this paper we argue that the brain, viewed as a representational system aimed at interpreting the world, possesses an ontology too. It decomposes target (...) space in a way that exhibits certain invariances, which in turn are functionally significant. A challenge for empirical research is to determine which are the functional regularities guiding this decomposition process. What are the explicit and implicit assumptions about the structure of reality, which at the same time shape the causal profile of the brain's motor output and the representational deep structure of the conscious mind arising from it (its "phenomenal output")? How do they constrain high-level phenomena like conscious experience, the emergence of a first-person perspective, or social cognition? By reviewing a series of neuroscientific results, we focus on the contribution the motor system makes to this process. As it turns out, the motor system constructs goals, actions, and intending selves as basic constituents of the world it interprets. It does so by assigning a single, unified causal role to them. Empirical evidence now clearly shows how the brain actually codes movements and action goals in terms of multimodal representations of organism-object relations. Under a representationalist analysis, this process can be interpreted as an internal representation of the intentionality relation itself. We try to show how such a more complex form of representational content, once it is in place, can later function as the building block for social cognition and a for more complex, consciously experienced representation of the first-person perspective as well. The motor system may therefore play a decisive role in understanding how the functional ontology of the human brain could be gradually extended into the subjective and social domains. (shrink)

This paper concerns how motor actions are neurally represented and coded. Action planning and motor preparation can be studied using a specific type of representational activity, motor imagery. A close functional equivalence between motor imagery and motor preparation is suggested by the positive effects of imagining movements on motor learning, the similarity between the neural structures involved, and the similar physiological correlates observed in both imaging and preparing. The content of motor representations can (...) be inferred from motor images at a macroscopic level, based on global aspects of the action and the motor rules and constraints which predict the spatial path and kinematics of movements. A more microscopic neural account calls for a representation of object-oriented action. Object attributes are processed in different neural pathways depending on the kind of task the subject is performing. During object-oriented action, a pragmatic representation is activated in which object affordances are transformed into specific motor schemas. Animal as well as human clinical data implicate the posterior parietal and premotor cortical areas in schema instantiation. A mechanism is proposed that is able to encode the desired goal of the action and is applicable to different levels of representational organization. (shrink)

Objective: Basic temporal dysfunctions have been described in patients with schizophrenia, which may impact their ability to connect and synchronize with the outer world. The present study was conducted with the aim to distinguish between interval timing and synchronization difficulties and more generally the spatial-temporal organization disturbances for voluntary actions. A new sensorimotor synchronization task was developed to test these abilities. Method: Twenty-four chronic schizophrenia patients matched with 27 controls performed a spatial-tapping task in which finger taps were to (...) be produced in synchrony with a regular metronome to six visual targets presented around a virtual circle on a tactile screen. Isochronous (time intervals of 500 ms) and non-isochronous auditory sequences (alternated time intervals of 300/600 ms) were presented. The capacity to produce time intervals accurately versus the ability to synchronize own actions (tap) with external events (tone) were measured. Results: Patients with schizophrenia were able to produce the tapping patterns of both isochronous and non-isochronous auditory sequences as accurately as controls producing inter-response intervals close to the expected interval of 500 and 900 ms, respectively. However, the synchronization performances revealed significantly more positive asynchrony means (but similar variances) in the patient group than in the control group for both types of auditory sequences. Conclusion: The patterns of results suggest that patients with schizophrenia are able to perceive and produce both simple and complex sequences of time intervals but are impaired in the ability to synchronize their actions with external events. These findings suggest a specific deficit in predictive timing, which may be at the core of early symptoms previously described in schizophrenia. (shrink)

Posterior parietal cortex has traditionally been considered to be a sensory association area in which higher-order processing and intermodal integration of incoming sensory information occurs. In this paper, evidence from clinical reports and from lesion and behavioral-electrophysiological experiments using monkeys is reviewed and discussed in relation to the overall functional organization of posterior parietal association cortex, and particularly with respect to a proposed posterior parietal mechanism concerned with the initiation and control of certain classes of eye and limb movements. (...) Preliminary data from studies of the effects of posterior parietal lesions on oculomotor control in monkeys are reported.The behavioral effects of lesions of posterior parietal cortex in monkeys have been found to be similar to those which follow analogous damage of the minor hemisphere in humans, while behavioral-electrophysiological experiments have disclosed classes of neurons in this area which have functional properties closely related to the behavioral acts that are disrupted by lesions of the area. On the basis of current data from these areas of study, it is proposed that the sensory association model of posterior parietal function is inadequate to account for the complexities of the present evidence. Instead, it now appears that many diverse neural mechanisms are locatedin partin parietal cortex, that some of these mechanisms are involved in sensory processing and perceptual functions, but that others participate in motor control, and that still others are involved in attentional, motivational, or emotional processes. It is further proposed that the elementary units of these various neural mechanisms are distributed within posterior parietal cortex according to the columnar hypothesis of Mountcastle. (shrink)

This work is descriptive observational, with transversal design, was to analyze the time of motor commitment in Physical Education classes in three subsystems of Venezuelan education. The analysis unit consisted of a discretionary sample of 6 Physical Education classes between initial education, basic education and secondary education, at the rate of 2 classes for each subsystem. The number of students participating was 192. For the observation and registration, was used, the temporal variables were recorded, and in the second instance, (...) the classes were recorded considering variables associated with: organization of groups, activities, disposition of materials, use and distribution of physical space. The results confirm the little use of the Physical Education class to favor the motor development; none of the observed classes managed to accumulate 50% of the time of motor commitment, thus confirming the trend of other investigations. (shrink)

Current views of the control of complex, purposeful movements acknowledge that organizational processes must reconcile multiple concerns. The central priority is of course accomplishing the actor's goal. But in specifying the manner in which this occurs, the action plan must accommodate such factors as the interaction of mechanical forces associated with the motion of a multilinked system (classical mechanics) and, in many cases, intrinsic bias toward preferred movement patterns, characterized by so‐called “coordination dynamics.” The most familiar example of the latter (...) is the symmetry constraint, where spatial trajectories and/or temporal landmarks (e.g., reversal points) of concurrentlymoving body segments (limbs, digits, etc.) exhibit mutual attraction. The natural coordination tendencies that emerge through these constraints can facilitate or hinder motor control, depending on the degree of congruency with the desired movement pattern. Motor control theorists have long recognized the role of classical mechanics in theories of movement organization, but an appreciation of the importance of intrinsic interlimb bias has been gained only recently.Although detailed descriptions of temporal coordination dynamics have been provided, systematic attempts to identify additional salient dimensions of interlimb constraint have been lacking. We develop and implement here a novel method for examining this problem by exploiting two robust principles of psychomotor behavior, the symmetry constraint and the Two‐Thirds Power Law. Empirical evidence is provided that the relative spatial patterns of concurrently moving limbs are naturally constrained in much the same manner as previously identified temporal constraints and, further, that apparent velocity interference is an indirect, secondary consequence of primary spatial assimilation. The theoretical implications of spatial interference are elaborated with respect to movement organization and motor learning. The need to carefully consider the appropriate dimensions with which to characterize coordination dynamics is also discussed. (shrink)

Current views of the control of complex, purposeful movements acknowledge that organizational processes must reconcile multiple concerns. The central priority is of course accomplishing the actor's goal. But in specifying the manner in which this occurs, the action plan must accommodate such factors as the interaction of mechanical forces associated with the motion of a multilinked system (classical mechanics) and, in many cases, intrinsic bias toward preferred movement patterns, characterized by so-called “coordination dynamics.” The most familiar example of the latter (...) is the symmetry constraint, where spatial trajectories and/or temporal landmarks (e.g., reversal points) of concurrentlymoving body segments (limbs, digits, etc.) exhibit mutual attraction. The natural coordination tendencies that emerge through these constraints can facilitate or hinder motor control, depending on the degree of congruency with the desired movement pattern. Motor control theorists have long recognized the role of classical mechanics in theories of movement organization, but an appreciation of the importance of intrinsic interlimb bias has been gained only recently.Although detailed descriptions of temporal coordination dynamics have been provided, systematic attempts to identify additional salient dimensions of interlimb constraint have been lacking. We develop and implement here a novel method for examining this problem by exploiting two robust principles of psychomotor behavior, the symmetry constraint and the Two-Thirds Power Law. Empirical evidence is provided that the relative spatial patterns of concurrently moving limbs are naturally constrained in much the same manner as previously identified temporal constraints and, further, that apparent velocity interference is an indirect, secondary consequence of primary spatial assimilation. The theoretical implications of spatial interference are elaborated with respect to movement organization and motor learning. The need to carefully consider the appropriate dimensions with which to characterize coordination dynamics is also discussed. (shrink)

A growing body of evidence in cognitive psychology and neuroscience suggests a deep interconnection between sensory-motor and language systems in the brain. Based on recent neurophysiological findings on the anatomo-functional organization of the fronto-parietal network, we present a computational model showing that language processing may have reused or co-developed organizing principles, functionality, and learning mechanisms typical of premotor circuit. The proposed model combines principles of Hebbian topological self-organization and prediction learning. Trained on sequences of either motor (...) or linguistic units, the network develops independent neuronal chains, formed by dedicated nodes encoding only context-specific stimuli. Moreover, neurons responding to the same stimulus or class of stimuli tend to cluster together to form topologically connected areas similar to those observed in the brain cortex. Simulations support a unitary explanatory framework reconciling neurophysiological motor data with established behavioral evidence on lexical acquisition, access, and recall. (shrink)

Central question of this essay is, whether it is possible to relate specific aspects of the organization of sensorimotor systems to specific aspects of the behaviour. The role of the auditory system as part of a system for vocalization or as part of a system for prey localization and the different roles of the trigeminal system in the feeding behaviour of different birds are considered. The ascending sensory systems seem to possess a comparable organization in the various species. (...) Also the descending motor pathways from archistriatum and paleostriatal complex seem to be basically similar. Behavioural specialization may be expressed particularly in the organization of the intratelencephalic circuits and thus in the involvement of specific regions of neostriatum and hyperstriatum ventrale. In discussions on cerebralisation it will be necessary to take such differences in intratelencephalic organization into account. (shrink)

Performance of bimanual motor actions requires coordinated and integrated bilateral communication, but in some bimanual tasks, neural interactions and crosstalk might cause bilateral interference. The level of interference probably depends on the proportions of bilateral interneurons connecting homologous areas of the motor cortex in the two hemispheres. The neuromuscular system for proximal muscles has a higher number of bilateral interneurons connecting homologous areas of the motor cortex compared to distal muscles. Based on the differences in neurophysiological (...) class='Hi'>organization for proximal vs. distal effectors in the upper extremities, the purpose of the present experiment was to evaluate how the level of bilateral interference depends on whether the bilateral interference task is performed with homologous or non-homologous effectors as the primary task. Fourteen participants first performed a unilateral primary motor task with the dominant arm with proximal and distal controlled joysticks. Performance in the unilateral condition with the dominant arm was compared to the same effector’s performance when two different bilateral interference tasks were performed simultaneously with the non-dominant arm. The two different bilateral interference tasks were subdivided into homologous and non-homologous effectors. The results showed a significant decrease in performance for both proximal and distal controlled joysticks, and this effect was independent of whether the bilateral interference tasks were introduced with homologous or non-homologous effectors. The overall performance decrease as a result of bilateral interference was larger for proximal compared to distal controlled joysticks. Furthermore, a proximal bilateral interference caused a larger performance decrement independent of whether the primary motor task was controlled by a proximal or distal joystick. A novel finding was that the distal joystick performance equally interfered with either homologous or non-homologous interference tasks performed simultaneously. The results indicate that the proximal–distal distinction is an important organismic constraint on motor control and for understanding bilateral communication and interference in general and, in particular, how bilateral interference caused by homologous vs. non-homologous effectors impacts motor performance for proximal and distal effectors. The results seem to map neuroanatomical and neurophysiological differences for these effectors. (shrink)

Unless one embraces activities as foundational, understanding activities in mechanisms requires an account of the means by which entities in biological mechanisms engage in their activities—an account that does not merely explain activities in terms of more basic entities and activities. Recent biological research on molecular motors exemplifies such an account, one that explains activities in terms of free energy and constraints. After describing the characteristic “stepping” activities of these molecules and mapping the stages of those steps onto the stages (...) of the motors’ hydrolytic cycles, researchers pieced together from images of the molecules in different hydrolyzation states accounts of how the chemical energy in ATP is transformed in the constrained environments of the motors into the characteristic activities of the motors. We argue that New Mechanism’s standard set of analytic categories—entities, activities, and organization—should be expanded to include constraints and energetics. Not only is such an expansion required descriptively to capture research on molecular motors but, more importantly from a philosophical point of view, it enables a non-regressive account of activities in mechanisms. In other words, this expansion enables a philosophical account of mechanistic explanation that avoids a regress of entities and activities “all the way down.” Rather, mechanistic explanation bottoms out in constraints and energetics. (shrink)

Schistosomes are parasitic blood flukes, responsible for significant human disease in tropical and developing nations. Here we review information on the organization of the cytoskeleton and associated motor proteins of schistosomes, with particular reference to the organization of the syncytial tegument, a unique cellular adaptation of these and other neodermatan flatworms. Extensive EST databases show that the molecular constituents of the cytoskeleton and associated molecular systems are likely to be similar to those of other eukaryotes, although there (...) are potentially some molecules unique to schistosomes and platyhelminths. The biology of some components, particular those contributing to host–parasite interactions as well as chemotherapy and immunotherapy are discussed. Unresolved questions in relation to the structure and function of the tegument relate to dynamic organization of the syncytial layer. BioEssays 26:752–765, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

To what extent is the neural organization of language dependent on factors specific to the modalities in which language is perceived and through which it is produced? That is, is the left-hemisphere dominance for language a function of a linguistic specialization or a function of some domain-general specialization(s), such as temporal processing or motor planning? Investigations of the neurobiology of signed language can help answer these questions. As with spoken languages, signed languages of the deaf display complex grammatical (...) structure but are perceived and produced via radically different modalities. Thus, by mapping out the neurological similarities and differences between signed and spoken language, it is possible to identify modality-specific contributions to brain organization for language. Research to date has shown a significant degree of similarity in the neurobiology of signed and spoken languages, suggesting that the neural organization of language is largely modality-independent. (shrink)

Hyundai Motor Company (HMC) has departed from the general tendency in the neoliberal era toward labor casualization. Nonregular workers at HMC have succeeded in having their employment status converted from precarious to permanent. I investigate why informal workers at HMC have been more successful in regularizing their status than informal workers in the shipbuilding industry. I contend that the deskilled labor process in automobile production provides favorable conditions for informal workers to organize themselves and stage disruptive protests. These differences (...) in the labor process, however, cannot fully explain the success of HMC given the failure in other automobile factories. I argue that self-organization and protests led by rank-and-file informal workers as well as solidarity from left-leaning formal workers played decisive roles in formalizing informal workers at HMC. I conclude by stressing the importance of structural conditions and workers’ collective actions in explaining the divergent outcomes in limiting dualization. (shrink)

Seemingly small changes in brain organization can have revolutionary consequences for function. An example is evolution's application of the primate action-planning mechanism to the management of communicative sequences. When feedback from utterances reaches the brain again through a mechanism that evolved to monitor action sequences, it makes another pass through the brain, amplifying the human power of thinking.

It is now generally accepted that the motor system is not purely dedicated to the control of behavior, but also has cognitive functions. Mirror neurons have provided a new perspective on how sensory information regarding others’ actions and gestures is coupled with the internal cortical motor representation of them. This coupling allows an individual to enrich his interpretation of the social world through the activation of his own motor representations. Such mechanisms have been highly preserved in evolution (...) as they are present in humans, apes and monkeys. Recent neuroanatomical data showed that there are two different connectivity patterns in mirror neuron networks in the macaque: one is concerned with sensorimotor transformation in relation to reaching and hand grasping within the traditional parietal-premotor circuits; the second one is linked to the mouth/face motor control and the new data show that it is connected with limbic structures. The mouth mirror sector seems to be wired not only for ingestive behaviors but also for orofacial communicative gestures and vocalizations. Notably, the hand and mouth mirror networks partially overlap, suggesting the importance of hand-mouth synergies not only for sensorimotor transformation, but also for communicative purposes in order to better convey and control social signals. (shrink)

A review of the scanty Gestaltist literature on motor behaviour indicates that a genuine Gestalt theoretic approach to motor behaviour can be characterized by three research questions: (1) What are the natural units of motor behaviour? (2) What characterizes the self-organization in motor behaviour? (3) What are the conditions for invariance in motor behaviour? Tentative answers to these questions can be found by analysing the parallels between Gestalt theory and Bernstein's theory of motor (...) actions and by showing that Gestalt theory can be regarded as a specific approach to non-linear dynamics as exemplified by synergetics (Haken, 1991). The congruence between the Gestalt theoretic approach and synergetics becomes apparent in the analysis of how a complex motor task is learned [1]. (shrink)

We review studies that indicate a dissociation between the perceptual estimate and the resulting cognitive representation of given properties of a seen object, on the one hand, and the motor action exerted on the same object. We propose that there exist multiple levels of organization of sensorimotor loops and that internal models may be made accessible to one level of organization while remaining inaccessible to another level.

The cellular processes of transport, division and, possibly, early development all involve microtubule‐based motors. Recent work shows that, unexpectedly, many of these cellular functions are carried out by different types of kinesin and kinesin‐related motor proteins. The kinesin proteins are a large and rapidly growing family of microtubule‐motor proteins that share a 340‐amino‐acid motor domain. Phylogenetic analysis of the conserved motor domains groups the kinesin proteins into a number of subfamilies, the members of which exhibit a (...) common molecular organization and related functions. The kinesin proteins that belong to different subfamilies differ in their rates and polarity of movement along microtubules, and probably in the particles/organelles that they transport. The kinesins arose early in eukaryotic evolution and gene duplication has allowed functional specialization to occur, resulting in a surprisingly large number of different classes of these proteins adapted for intracellular transport of vesicles and organelles, and for assembly and force generation in the meiotic and mitotic spindles. (shrink)

To what extent is the neural organization of language dependent on factors specific to the modalities in which language is perceived and through which it is produced? That is, is the left-hemisphere dominance for language a function of a linguistic specialization or a function of some domain-general specialization, such as temporal processing or motor planning? Investigations of the neurobiology of signed language can help answer these questions. As with spoken languages, signed languages of the deaf display complex grammatical (...) structure but are perceived and produced via radically different modalities. Thus, by mapping out the neurological similarities and differences between signed and spoken language, it is possible to identify modality-specific contributions to brain organization for language. Research to date has shown a significant degree of similarity in the neurobiology of signed and spoken languages, suggesting that the neural organization of language is largely modality-independent. (shrink)

Although the following essay is literary-philosophical, it arose from a practical interest. I have been struck by how widespread today is the complaint about the ‘inadequate father’. Of course a father may be inadequate in diverse ways, either absconding, absent and weak, or overbearing, bullying, and tyrannical, or some combination of these. Further, I am not restricting the term ‘father’ to its narrow biological sense, but using it rather as a metaphor for any institution or structure which an individual or (...) a group feels should have been in place to guide, direct, and protect them in important situations, but did not do its job properly. Consequently they are willing to concede they are not all they could have been, but they insist it is not their fault, rather the fault of the ‘father’ who should have done his job better. This ties in with the fashionable appeal of ‘victimhood’. Everybody today seems to want to cast themselves as a ‘victim’, for reasons similar to those mentioned above. If you are a ‘victim’, then there must be an ‘oppressor’– and some ‘parent’ organization that should have guided, directed, and protected you against the oppressor, but again did not do its job adequately. It is striking how many individuals and groups around the world today choose to perceive themselves, and to present themselves to others, as ‘victims’; it has indeed become a preferred characterization of our age, for it carries with it a rhetorical advantage that trumps all others. If you are able to cast yourself as a ‘victim’, and have others accept this, you disarm and neutralize criticism, not only of what you are, but of what you are currently doing – because the latter can be presented as a just ‘compensation’ for what you have suffered. As with guilt, there is no built-in quota or statute of limitations. This rhetoric was not as common thirty or forty years ago.There is an added factor here in America and the New World generally where, according to a whispered criticism, as our ancestors crossed the ocean, they experienced a ‘drop in civilization’. Life here was initially without some of the structures and institutions which had evolved over thousands of years in the Old World, which could thus be presumed there but here were absent. As we won with difficulty our independence, we unconsciously repudiated much of the ‘higher culture’ of the colonial master, throwing out the baby with the bathwater. As the ‘economic bubble’ of having won the Second World War has gradually dissipated, we discover we are handicapped by an absence of the forms of maturation and self-realization that arise in and are necessary for dealing with prolonged peace. In our ‘ideology of liberty’, our adults become essentially grown children, unschooled in anything higher, and thus have particular difficulty assuming the responsibilities of parenthood. They are forced to fall back upon a military style of giving orders, because on this side of the water, ‘final causes’ in the form of commonly admired or agreed on goals for striving are not in place. In this sense there is an absence of the ‘adequate father’. Further, as ‘American Culture’ expands through publicity and the media, we spread the same disease.There is another relevant factor, the ‘celebrity-liberationist’ lifestyle that has been diffused into the general population since the 1960's and has become a default secular ethic of our time, replacing the traditional Judeo-Christian decalogue. The former is invoked as a justification for aggressively seeking fame and fortune, and making no attempt to conceal this; rather than worrying that such an attitude will cause offense, it is worn proudly and defiantly in the hope that others will identify with it, thereby branding the performer a cultural hero. This popular strategy towards fulfilment itself rests on a metaphysic of ‘expressive individualism’, a position that holds that the supreme ethical imperative to which other obligations must be subordinated is for each to bring forward their hidden noumenal core, the only source of value, into phenomenal appearances where it may be admired and benefit others and such that creation will for the first time be complete. This change in Western culture made possible by greater affluence and security represents a trickle-down phenomenon and democritization of the awe reserved for the artist revered as a genius during the nineteenth century, now spread to the entire population. Anything that constrains this expansion, which interrupts or limits this transfer, is to be rejected as parental abuse, psychological repression, or cultural imperialism. (shrink)

For patients with multiple sclerosis, deficits in gait significantly reduce the quality of life. Using the concept of muscle synergies, this study investigated the modular organization of motor control during level and inclined walking in MS patients compared with healthy participants to identify the potential demand-specific adjustments in motor control in MSP. We hypothesized a widening of the time-dependent activation patterns in MSP to increase the overlap of temporally-adjacent muscle synergies, especially during inclined walking, as a strategy (...) to increase the robustness of motor control, thus compensating pathology-related deficits. We analyzed temporal gait parameters and muscle synergies from myoelectric signals of 13 ipsilateral leg muscles using non-negative matrix factorization. Compared with HP, MSP demonstrated a widening in the time-dependent coefficients, as well as altered relative muscle contribution, in certain synergies during level and inclined walking. Moreover, inclined walking revealed a demand-specific adjustment in the modular organization in MSP, resulting in an extra synergy compared with HP. This further increased the overlap of temporally-adjacent muscle synergies to provide sufficient robustness in motor control to accomplish the more demanding motor task while coping with pathology-related motor deficits during walking. (shrink)

Aging is characterized by the decline and deterioration of functional cells and results in a wide variety of molecular damages and reduced physical and mental capacity. The knowledge on aging process is important because life expectancy is expected to rise until 2050. Aging cannot be considered a homogeneous process and includes different trajectories characterized by states of fitness, frailty, and disability. Frailty is a dynamic condition put between a normal functional state and disability, with reduced capacity to cope with stressors. (...) This geriatric syndrome affects physical, neuropsychological, and social domains and is driven by emotional and spiritual components. Sarcopenia is considered one of the determinants and the biological substrates of physical frailty. Physical and cognitive frailty are separately approached during daily clinical practice. The concept of motoric cognitive syndrome has partially changed this scenario, opening interesting windows toward future approaches. Thus, the purpose of this manuscript is to provide an excursus on current clinical practice, enforced by aneddoctical cases. The analysis of the current state of the art seems to support the urgent need of comprehensive organizational model incorporating physical and cognitive spheres in the same umbrella. (shrink)

This book is a selection of papers from a conference which took place at the University of Keele in July 1982. The conference was an extraordinarily enjoyable one, and we would like to take this opportunity of thanking all participants for helping to make it so. The conference was intended to allow scholars working on different aspects of symbolic behaviour to compare findings, to look for common ground, and to identify differences between the various areas. We hope that it was (...) successful in these aims: the assiduous reader may judge for himself. Several themes emerged during the course of the conference. Some of these were: 1. There is a distinction to be made between those symbol systems which attempt, more or less directly, to represent a state of affairs in the world (e. g. language, drawing, map and navigational skill) and those in which the representational function is complemented, if not overshadowed, by properties of the symbol system itself, and the systematic inter-relations that symbols can have to one another (e. g. music, mathematics). The distinction is not absolute, for the nature of all symbolic skills is, in part, a function of the structure of the symbolic system employed. Nonetheless, this distinction helps us to understand some common acquisition difficulties, such as that experienced in mathematics, where mental manipulation of symbols can go awry if a child assumes too close a correspondence between mathematical symbols and the world they represent. 2. (shrink)

Precise timing of muscle contractions is an important prerequisite for motor control and one to which the cerebellum contributes. Braitenberg et al.'s detailed timing hypotheses relate only to a subset of the known features of the organisation of the cerebellum. However, the cerebellar architecture clearly supports the that are central to the authors' proposal and such tidal waves are very likely to contribute to its functions.

Voluntary acts are preceded by electrophysiological (RPs). With spontaneous acts involving no preplanning, the main negative RP shift begins at about200 ms. Control experiments, in which a skin stimulus was timed (S), helped evaluate each subject's error in reporting the clock times for awareness of any perceived event.

Studies have shown that in the mammalian neuromuscular system stretch reflexes are localized within individual muscles. Neuromuscular compartmentalization, the partitioning of sensory output from muscles, and the partitioning of segmental pathways to motor nuclei have also been demonstrated. This evidence indicates that individual motor nuclei and the muscles they innervate are not homogeneous functional units. An analysis of the functional significance of reflex localization and partitioning suggests that segmental control mechanisms are based on subdivisions of motor nuclei–muscle (...) complexes. A partitioned organization of segmental control mechanisms could utilize (1) the potential functional diversity of muscle fiber types, (2) the variety of mechanical actions of individual muscles arising from their distributed origins and insertions, and (3) diverse architectural features such as intramuscular variations in pinnation and complex in-series and in-parallel arrangements of muscle fibers. The differentiated activity observed in some muscles during natural movements also calls for localized segmental control mechanisms. Partitioning may also play a role in mechanical interactions between contracting motor units and in increasing the stability of neuromuscular systems. The functional advantages of reflex localization and partitioning suggest they are probably common features of segmental systems, whose organization reflects the structure and function of their associated neuromuscular systems. (shrink)

Today, in a post-pandemic space, all types of art, comprehending, due to their figurative specificity, certain spheres of objective reality, already as a result of this, circumstances have their own, only inherent laws. Using the inexhaustible possibilities of the plasticity of the human body, choreography has refined and developed expressive dance movements for many centuries. As a result of this complex process, a system of choreographic movements arose, that is, a special artistic and expressive speech of plastics, constitutes the creative (...) material of dance imagery. Choreographic art includes various types of arts: music, choreography itself, drama, painting. Each of them, changing in accordance with the requirements of this type of art, becomes a necessary component of choreographic figurative thinking. Each type of art is achieved thanks to its own figurative specificity, patterns and certain pictorial and expressive means. Choreographic activity dictates its own laws of reflection of reality, is based not on the correspondence of life and artistic material, but on the degree of devotion to the metaphorical reflection of life. A comprehensive study of social constituting dance art in today's post-pandemic space is a complex and versatile task, it mainly involves the study of all its components. Moreover, each of them should be considered not in isolation, but in the general system of their internal connections - in the aspect of their rhythmic and metric, that is, motor organization. (shrink)

Organisation studies based on qualitative methodologies continually seek legitimacy in relation to positivist research formulating nomological knowledge on administrative practices. One of the key features regularly praised in qualitative research is the idea of reflexivity, the ability of the qualitative researcher to critically examine his or her own analysis. This paper argues that the notion of reflexivity is an uncontested area of qualitative organisation research which merits critical study. In contrast to the reflexivity model which assumes an autopoietic double hermeneutic (...) of the examined empirical material, it draws on Kierkegaard’s notion of subjective thinking. For Kierkegaard it is not reflexivity that serves as the primus motor for subjective thinking but doubt, paradox and passion. A critique of the notion of reflexivity opens up alternative accounts of qualitative research which need not assume self-correcting and self-directed analysis. (shrink)

Unlike Dickens’s novel, this is not a tale of light and darkness, order and chaos, good and evil… It is, though, a story worth to be told about two standpoints about games and sports, teaching and research, physical education simply put, that have pursued similar interests on parallel tracks for too long, despite their apparent closeness and expected shared cultural grounds. The objective of this conceptual analysis is to try and reconcile two perspectives, namely motor praxeology and teaching games (...) for understanding (TGfU), born in the last third of the XX century in France and England with the intention to rethink the foundations of physical education (PE) and sports teaching. Pierre Parlebas, from the French side of the English Channel, claimed in 1967 that sports make part of PE, that team sports must be considered from a specific, sociomotor point of view, and that motor conducts (i.e. the significative organization of motor behaviour), not sports techniques, are the corner-stone of PE and sports coaching. In the early 1980s, from the English side of La Manche, Almond, Thorpe, and Bunker made a plea for a shift in the way to teach games (sporting collective duels mostly), deeply concerned by the negative impact of the traditional technics-centred approach on motivation, competence and attained level of the least able in school situations. Our conclusion is that TGfU, or game-based approaches to sports coaching and teaching, can take great advantage of the motor-praxeological rationale for three reasons: firstly, because concepts like understanding, game sense and action principles are operatively, semiotically linked to the reality of the playing process; secondly, because the inner structures of the games that constrain players and guide their motor conducts, permit to integrate games in the general system of sporting games, no matter their level of institutionalisation; finally, because the intervention practice is better thought of and more systematically developed upon the operational concepts of internal logic and expected practical effects of game playing. This time, Paris could be the place to go to in search of solutions, not the city to run away from in hope of consolation. (shrink)