ABSTRACTThe seeming distinction between motor and cognitive skills has hinged on the fact that the former are automatic and non-propositional, whereas the latter are slow and deliberative. Here, the physiological and behavioral phenomenon of long-latency stretch reflexes is used to show that “knowing-that” can be incorporated into “knowing-how,” either immediately or through learning. The experimental demonstration that slow computations can, with practice, be cached for fast retrieval, without the need for re-computation, dissolves the intellectualist/anti-intellectualist distinction: All complex human (...) tasks, at any level of expertise, are a combination of intelligent reflexes and deliberative decisions. (shrink)

Functional electrical stimulation (FES), a method for inducing muscle contraction, has been successfully used in gait rehabilitation for patients with deficits after neurological disorders and several clinical studies have found that it can improve gait function after stroke and spinal cord injury. However, FES gait training is not suitable for patients with walking difficulty, such as those with severe motor paralysis of the lower limbs. We have previously shown that action observation combined with motor imagery (AO + MI) (...) of walking induces walking-related cortical activity. Therefore, we combined FES, which alternately generates dorsiflexion and plantar flexion, with AO + MI as an alternative to gait training. The present study investigates the transient effects of 20-min of FES simultaneously with and without AO + MI of walking on corticospinal and spinal reflex excitability in able-bodied participants. We measured motor evoked potentials and Hoffmann-reflexes to assess corticospinal and spinal reflex excitability at rest before and after the 20-min FES with and without the AO + MI. Our results show that FES without AO + MI did not change excitability (p > 0.05), while FES with AO + MI facilitated corticospinal excitability (p < 0.05). This facilitation likely occurred due to the synchronization of sensory inputs from FES and cortical activity during AO + MI. Facilitation was observed only in the dorsiflexor but not the plantar flexor muscle (p < 0.05), suggesting muscle specificity of the facilitation. These results demonstrate the effectiveness of combining FES with AO + MI and pave the way for novel neurorehabilitation strategies for patients with neurological gait deficits. (shrink)

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)

BackgroundReflexive pitch perturbation experiments are commonly used to investigate the neural mechanisms underlying vocal motor control. In these experiments, the fundamental frequency–the acoustic correlate of pitch–of a speech signal is shifted unexpectedly and played back to the speaker via headphones in near real-time. In response to the shift, speakers increase or decrease their fundamental frequency in the direction opposing the shift so that their perceived pitch is closer to what they intended. The goal of the current work is to (...) develop a quantitative model of responses to reflexive perturbations that can be interpreted in terms of the physiological mechanisms underlying the response and that captures both group-mean data and individual subject responses.MethodsA model framework was established that allowed the specification of several models based on Proportional-Integral-Derivative and State-Space/Directions Into Velocities of Articulators (DIVA) model classes. The performance of 19 models was compared in fitting experimental data from two published studies. The models were evaluated in terms of their ability to capture both population-level responses and individual differences in sensorimotor control processes.ResultsA three-parameter DIVA model performed best when fitting group-mean data from both studies; this model is equivalent to a single-rate state-space model and a first-order low pass filter model. The same model also provided stable estimates of parameters across samples from individual subject data and performed among the best models to differentiate between subjects. The three parameters correspond to gains in the auditory feedback controller’s response to a perceived error, the delay of this response, and the gain of the somatosensory feedback controller’s “resistance” to this correction. Excellent fits were also obtained from a four-parameter model with an additional auditory velocity error term; this model was better able to capture multi-component reflexive responses seen in some individual subjects.ConclusionOur results demonstrate the stereotyped nature of an individual’s responses to pitch perturbations. Further, we identified a model that captures population responses to pitch perturbations and characterizes individual differences in a stable manner with parameters that relate to underlying motor control capabilities. Future work will evaluate the model in characterizing responses from individuals with communication disorders. (shrink)

The vestibulo-ocular reflex (VOR) adaptation is an ideal model for investigating how the neurosteroid 17 beta-estradiol (E2) contributes to the modification of behavior by regulating synaptic activities. We hypothesized that E2 impacts VOR adaptation by affecting cerebellar synaptic plasticity at the parallel fiber–Purkinje cell (PF) synapse. To verify this hypothesis, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in adaptation of the VOR in male rats using an oral dose (2.5 mg/kg) of the aromatase (...) inhibitor letrozole. We also assessed the effect of letrozole on synaptic plasticity at the PF synapse in vitro, using cerebellar slices from male rats. We found that letrozole acutely impaired both gain increases and decreases adaptation of the VOR without altering basal ocular-motor performance. Moreover, letrozole prevented long-term potentiation at the PF synapse (PF-LTP) without affecting long-term depression (PF-LTD). Thus, in male rats neurosteroid E2 has a relevant impact on VOR adaptation and affects exclusively PF-LTP. These findings suggest that E2 might regulate changes in VOR adaptation by acting locally on cerebellar and extra-cerebellar synaptic plasticity sites. (shrink)

The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behaviour against the volitional control of a goal-directed behaviour. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behaviour and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following two weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following two weeks of training; however this increased (...) speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions. (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)

The output from motor neuron pools is influenced by the integration of synaptic inputs originating from descending corticomotor and spinal reflex pathways. In this study, using paired non-invasive brain and peripheral nerve stimulation, we investigated how descending corticomotor pathways influence the physiologic recruitment order of the soleus Hoffmann reflex. Eleven neurologically unimpaired adults completed an assessment of transcranial magnetic stimulation -conditioning of the soleus H-reflex over a range of peripheral nerve stimulation intensities. Unconditioned H-reflex recruitment curves were obtained by (...) delivering PNS pulses to the posterior tibial nerve. Subsequently, TMS-conditioned H-reflex recruitment curves were obtained by pairing PNS with subthreshold TMS at short and long intervals. We evaluated unconditioned and TMS-conditioned H-reflex amplitudes along the ascending limb, peak, and descending limb of the H-reflex recruitment curve. Our results revealed that, for long-interval facilitation, TMS-conditioned H-reflex amplitudes were significantly larger than unconditioned H-reflex amplitudes along the ascending limb and peak of the H-reflex recruitment curve. Additionally, significantly lower PNS intensities were needed to elicit peak H-reflex amplitude for long-interval facilitation compared to unconditioned. These findings suggest that the influence of descending corticomotor pathways, particularly those mediating long-interval facilitation, contribute to changing the recruitment gain of the motor neuron pool, and can inform future methodological protocols for TMS-conditioning of H-reflexes. By characterizing and inducing short-term plasticity in circuitry mediating short- and long-interval TMS-conditioning of H-reflex amplitudes, future studies can investigate supraspinal and spinal circuit contributions to abnormal motor control, as well as develop novel therapeutic targets for neuromodulation. (shrink)

Neurosteroid 17 beta-estradiol (E2) is a steroid synthesized de novo in the nervous system that might influence neuronal activity and behavior. Nevertheless, the impact of E2 on the functioning of those neural systems in which it is slightly synthesized is less questioned. The vestibulo-ocular reflex (VOR) adaptation, may provide an ideal arena for investigating this issue. Indeed, E2 modulates cerebellar parallel fiber-Purkinje cell synaptic plasticity that underlies encoding of VOR adaptation. Moreover, aromatase expression in the cerebellum of adult rodents is (...) maintained at very low levels and localized to Purkinje cells. The significance of age-related maintenance of low levels of aromatase expression in the cerebellum on behavior, however, has yet to be explored. Our aim in this study was to determine whether E2 synthesis exerts an effective and persistent modulation of VOR adaptation in adult male rats. To answer this question, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in VOR adaptation using an oral dose (2.5 mg/kg) of the aromatase inhibitor Letrozole in peri-pubertal and post-pubertal male rats. We found that Letrozole acutely impaired gain increases and decreases in VOR adaptation without altering basal ocular-motor performance and that these effects were similar in peri-pubertal and post-pubertal rats. Thus, in adult male rats neurosteroid E2 effectively modulates VOR adaptation in both of the periods studied. These findings imply that the adult cerebellum uses E2 synthesis for modulating motor memory formation and suggest that low and extremely localized E2 production may play a role in adaptive phenomena. (shrink)

PET studies using classical conditioning paradigms are reported. It is emphasized that PET studies show and not in learning paradigms. The importance of dissociating motor performance and learning deficits in human lesions studies is demonstrated in two exemplary studies. The different role of the cerebellum in adaptation of postural reflexes and learning of complex voluntary arm movements is discussed, [THACH].

The lambda model provides a physiologically grounded terminology for describing muscle function and emphasizes the important influence of environmental and reflex-mediated effects on final states. However, lambda itself is only a convenient point on the length-tension curve; its importance should not be overemphasized. Ascribing movement to changes in a lambda-based frame of reference is generally valid, but it leaves unanswered a number of questions concerning mechanisms.

In a previous paper it was suggested that specific concepts are needed in the psychological sciences and the basic mental triad was described as a useful tool to further our understanding of mentation. It was stated that the sensori-motor reflex principle cannot describe and explain mental phenomena, because the reflex is basically a mechanistic occurrence, while mental phenomena differ in essence from mechanisms. Since conditioned reflexes can be conceived as sensori-motor reflexes with another, non-mechanistic factor superimposed, (...) similarities and contrasts between reflexes and conditioned reflexes were taken as the material from which one can develop new thoughts about mentation. Reflex shutting of the eyelid, caused by direct contact between cornea and a small, invisible foreign body was compared with and contrasted to shutting the eye before a large, visible object thrusting toward the eye. It was shown that reflexes occur in response to a stimulus after the stimulus has been applied, while conditioned reflexes seem to anticipate the stimulus. This was taken as evidence that conditioned reflexes have a protensive character, have a relationship to the future, which sensori-motor reflexes lack. This difference in time relationship was developed into the statement that the difference between mechanisms and mental phenomena lies in their different relationship to the future. The need for specific concepts to describe mental phenomena stems from the inability of the reflex principle to deal with the protensive tendency of mental phenomena and to fill this need the concept of the basic mental triad was offered. This principle consists of three interdependent, interwoven phases: the triad connects with the past through condensation of some of the subject's past experience into a vaguely formed conglomerate; it connects with the future by projecting the condensed past into the future; the central phase of the triad is the act within the present instant, where a synthesis of past, present and future is accomplished. (shrink)

This target article draws together two groups of experimental studies on the control of human movement through peripheral feedback and centrally generated signals of motor commands. First, during natural movement, feedback from muscle, joint, and cutaneous afferents changes; in human subjects these changes have reflex and kinesthetic consequences. Recent psychophysical and microneurographic evidence suggests that joint and even cutaneous afferents may have a proprioceptive role. Second, the role of centrally generated motor commands in the control of normal movements (...) and movements following acute and chronic deafferentation is reviewed. There is increasing evidence that subjects can perceive their motor commands under various conditions, but that this is inadequate for normal movement; deficits in motor performance arise when the reliance on proprioceptive feedback is abolished either experimentally or because of pathology. During natural movement, the CNS appears to have access to functionally useful input from a range of peripheral receptors as well as from internally generated command signals. The unanswered questions that remain suggest a number of avenues for further research. (shrink)

This article presents the pedagogical paradigm of reflexive interaction and its application in the field of technology-enhanced learning and children’s musical creativity. The main feature of reflexive interaction is the repetition-variation mechanism: something is repeated and varied during the interaction, through a continual process of imitation and variation. In the context of the MIROR project (EU-ICT Project), we exploited the educational potential of the reflexive interaction paradigm and implemented the MIROR platform, an educational device consisting of a set of softwares (...) that implement the reflexive paradigm not only in music improvisation (as was the case for the first interactive reflexive system), but also in the field of music composition and dance. The platform was conceived as a tool to stimulate and develop musical and motor creativity in children, although it can also be used to teach a specific musical instrument. The hypothesis of the MIROR project was that reflexive interaction sustains and promotes the learning and creative expression processes of music and movement. This initial hypothesis, which stemmed mainly from the pilot study in which we observed children who were interacting with the first prototype of the interactive reflexive musical system, was subjected to a series of empirical studies conducted within the MIROR project, and was theoretically defined in order to lay down the foundations of the reflexive interaction paradigm and its pedagogical implications. This article summarizes the state-of-the-art of the project and brings together, in a comprehensive overview, the theoretical framework, the pedagogical concepts, the empirical studies, and the description of the MIROR platform, with the aim to reflect on the results achieved so far and point out the contribution of the reflexive perspective to the field of children’s instrumental learning and creativity. (shrink)

Most conceptual models of the organization of the cardiovascular system begin with the premise that the nervous system regulates the metabolic and nonmetabolic reflex adjustments of the circulation. These models assume that all the neurally mediated responses of the circulation are reactive, i.e., reflexes elicited by adequate stimuli. This target article suggests that the responses of the circulation are conditional in three senses. First, as Sherrington argued, reflexes are conditional in that they never operate in a vacuum but (...) in a context together with other reflexes. Guided by functional utility, they interact rather than add. Second, as Pavlov argued, stimuli acquire meanings as a result of experience. This notion of stimulus effect plus the Sherringtonian notion of conditionality suggest that association is one of the ways stimuli eliciting cardiovascular reflexes acquire their meanings and thus their relative strengths. Finally, as Skinner and others have argued, operants are responses that act upon the environment to obtain consequences – that is, stimuli. As operants, cardiovascular responses fulfill a major biological need, functioning proactively. The cardiovascular response is an integral component of the animal's behavior regardless of whether it is an elicited reflex or the eliciting stimulus acquired its properties as a result of the genetic inheritance of the animal or through experience, or the cardiovascular response is emitted in anticipation of an environmental consequence. The main theses of this essay are: (1) behavior is an integrated set of responses and the circulation is one of the response systems comprising behavior; (2) behavior is, in part, determined by its functional significance within a context; (3) the contextual factors operative at the time of the behavior have a major role in determining which of the set of possible responses will determine the final act, that is, which behavior will be the effective response and which other behaviors will be concomitants. (shrink)

Complex regional pain syndromes (reflex sympathetic dystrophy, causalgia) are often characterized by pain and autonomic and motor abnormalities. Pathophysiological mechanisms are in the central and peripheral nervous system. Differences in skin temperature and may be used as diagnostic criteria. Sympathetic blocks relieve pain and other symptoms in a subgroup of patients (sympathetically maintained pain, SMP).[blumberg et al.].

Western science claims to provide unique, objective information about the world. This is supported by the observation that peoples across cultures will agree upon a common description of the physical world. Further, the use of scientific instruments and mathematics is claimed to enable the objectification of science. In this work, carried out by reviewing the scientific literature, the above claims are disputed systematically by evaluating the definition of physical reality and the scientific method, showing that empiricism relies ultimately upon the (...) human senses for the evaluation of scientific theories and that measuring instruments cannot replace the human sensory system. Nativist and constructivist theories of human sensory development are reviewed, and it is shown that nativist claims of core conceptual knowledge cannot be supported by the findings in the literature, which shows that perception does not simply arise from a process of maturation. Instead, sensory function requires a long process of learning through interactions with the environment. To more rigorously define physical reality and systematically evaluate the stability of perception, and thus the basis of empiricism, the development of the method of dimension analysis is reviewed. It is shown that this methodology, relied upon for the mathematical analysis of physical quantities, is itself based upon empiricism, and that all of physical reality can be described in terms of the three fundamental dimensions of mass, length and time. Hereafter the sensory modalities that inform us about these three dimensions are systematically evaluated. The following careful analysis of neuronal plasticity in these modalities shows that all the relevant senses acquire from the environment the capacity to apprehend physical reality. It is concluded that physical reality is acquired rather than given innately, and leads to the position that science cannot provide unique results. Rather, those it can provide are sufficient for a particular environmental setting. (shrink)

In his interesting commentary, Joshua Shepherd raises two points—one related to epistemology, the other to ethics—about our article on human cerebral organoids.1 2 From the epistemological standpoint, he calls into question the need for a theory of consciousness. A theory of consciousness, for him, is not necessary because of the lack of consensus about the very nature of consciousness. Shepherd suggests that ‘given widespread disagreement, applying a theory of consciousness may not be helpful when attempting to diagnose the presence of (...) consciousness in cerebral organoids’. In Shepherd’s view, it would be better to transfer ‘concepts already under development in work on the presence and structure of consciousness in difficult marginal cases involving traumatic brain injury’.2 We could not agree more on this last point; detecting a minimal capacity for consciousness in the brain of comatose patients is a very similar challenge to inferring the presence of consciousness in cerebral organoids. Every day, as a by-product of saving many lives, intensive care medicine artificially produces thousands of brains that may remain isolated, split or fragmented; in the worst case, cortical islands, or an archipelago of islands, may survive while being disconnected from the outside world. Can these islands host some form of consciousness? That is, does it feel like anything to be a large piece of human cortex? Addressing this difficult question requires the development of general, objective brain-based indices of consciousness that are independent of sensory processing, executive functions and motor outputs.3 Consider, for example, a patient showing reflexive spontaneous behaviour, no response to command and no ability to communicate. In her brain, afferent pathways are damaged, thereby impairing the recruitment of cortical areas in response to sensory stimulation; basal ganglia, as well as other frontal structures supporting executive functions, are impaired. However, resting metabolism and significant electroencephalography …. (shrink)

In this paper we focus on a kind of perceptual states that we call perceptual motivations, that is, perceptual experiences that plausibly motivate us to act, such as itching, perceptual salience and pain. Itching seems to motivate you to scratch, perceiving a stimulus as salient seems to motivate you to attend to it and feeling a pain in your hand seems to motivate actions such as withdrawing from the painful stimulus. Five main accounts of perceptual motivation are available: Descriptive, Conative, (...) Imperativist, Reflexive and Dual Content views. Some of these have been developed in detail and others are natural extensions of existing views. However, we argue that none provides a satisfactory account of the target perceptual states. Driven by the failings of each account, we identify three conditions that any satisfactory theory of perceptual motivation must meet: Direct Motivational Force, Non-Obligatory Force and Intention-Independent Influence. Then we offer an account that attempts to fulfil these conditions: the Affordance Model. This model of perceptual motivation is premised on the claim that each of the target states involves the perception of a specific affordance for action and the triggering of Automatic Motor Initiations (AMIs). We suggest that AMIs can explain the motivational force of these perceptual states. (shrink)

The Hoffmann reflex (H-wave) is produced by alpha-motoneuron activation in the spinal cord. A feature of this electromyography response is that it exhibits fluctuations in amplitude even during repetitive stimulation with the same intensity of current. We herein explore the hypothesis that physical training induces plastic changes in the motor system. Such changes are evaluated with the fractal dimension (FD) analysis of the H-wave amplitude-fluctuations (H-wave FD) and the cross-covariance (CCV) between the bilateral H-wave amplitudes. The aim of this (...) study was to compare the H-wave FD as well as the CCV before and after track training in sedentary individuals and athletes. The training modality in all subjects consisted of running three times per week (for 13 weeks) in a concrete road of 5 km. Given the different physical condition of sedentary vs. athletes, the running time between sedentary and athletes was different. After training, the FD was significantly increased in sedentary individuals but significantly reduced in athletes, although there were no changes in spinal excitability in either group of subjects. Moreover, the CCV between bilateral H-waves exhibited a significant increase in athletes but not in sedentary individuals. These differential changes in the FD and CCV indicate that the plastic changes in the complexity of the H-wave amplitude fluctuations as well as the synaptic inputs to the Ia-motoneuron systems of both legs were correlated to the previous fitness history of the subjects. Furthermore, these findings demonstrate that the FD and CCV can be employed as indexes to study plastic changes in the human motor system. (shrink)

The projection of conscious content is a central feature of Max Velmans' theory of consciousness, implying that conscious experiences are built within a conversation of minds and worlds in which they form a 'reflexive' unity – as stated in his reflexive monism theory. What are the neurobiological structures and functions that underpin the experience of conscious contents being located in a spatio-temporal frame outside the nervous system that instantiates them? In this paper I offer informed speculation about these neurobiological structures (...) on the basis of the concept of projection within the psychophysical 'egocentric space', having the central nervous system at the origin of coordinates and the interface with the environment as the horizon. The reasoning is based on the work of several neuroscientists on feedback signals from the motor to sensory neuron systems, building a picture of how they support the projective process. I also call attention to the integrative role of glial cells in the generation of localized sensations and other conscious contents. (shrink)

The use of upper limb vibration during exercise and rehabilitation continues to gain popularity as a modality to improve function and performance. Currently, a lack of knowledge of the pathways being altered during ULV limits its effective implementation. Therefore, the aim of this study was to investigate whether indirect ULV modulates transmission along spinal and corticospinal pathways that control the human forearm. All measures were assessed under CONTROL and ULV conditions while participants maintained a small contraction of the right flexor (...) carpi radialis muscle. To assess spinal pathways, Hoffmann reflexes elicited by stimulation of the median nerve were recorded from FCR with motor response amplitudes matched between conditions. An H-reflex conditioning paradigm was also used to assess changes in presynaptic inhibition by stimulating the superficial radial nerve 37 ms prior to median nerve stimulation. Cutaneous reflexes in FCR elicited by stimulation of the SR nerve at the wrist were also recorded. To assess corticospinal pathways, motor evoked potentials elicited by transcranial magnetic stimulation of the contralateral motor cortex were recorded from the right FCR and biceps brachii. ULV significantly reduced H-reflex amplitude by 15.7% for both conditioned and unconditioned reflexes. Therefore, ULV inhibits cutaneous and H-reflex transmission without influencing corticospinal excitability of the forearm flexors suggesting increased presynaptic inhibition of afferent transmission as a likely mechanism. A general increase in inhibition of spinal pathways with ULV may have important implications for improving rehabilitation for individuals with spasticity. (shrink)

To controlforceaccurately under a wide range of behavioral conditions, the central nervous system would either require a detailed, continuously updated representation of the state of each muscle (and the load against which each is acting) or else force feedback with sufficient gain to cope with variations in the properties of the muscles and loads. The evidence for force feedback with adequate gain or for an appropriate central representation is not sufficient to conclude that force is the major controlled variable in (...) normal limb movements.Morton's hypothesis, thatlengthis controlled by a follow-up servo, has a number of difficulties related to the delays, gains, variability, and specificity in feedback pathways comprising potential servo loops. However, experimental evidence is consistent with these pathways providing servo assistance for some movements produced by coactivation of α- and static γ-motoneurons. Dynamic γ-motoneurons may provide an additional input for adaptive control of different types of movements.The idea that feedback is used to compensate for changes in musclestiffnesshas received experimental support under static postural conditions. However, reflexes tend to increase rather than decrease the range of variation in muscle stiffness during some cyclic movements. Theoretical problems associated with the regulation of stiffness are also discussed. The possibilities of separate control systems forvelocityorviscosityare considered, but the evidence is either negative or lacking. I conclude that different physical variables can be controlled depending on the type of limb movement required. The concept of stiffness regulation is also useful under some conditions, but should probably be extended to the regulation of the visco-elastic properties (i.e., the mechanical impedance) of a muscle or joint. (shrink)

Previous research has suggested that bodily signals from internal organs are associated with diverse cortical and subcortical processes involved in sensory-motor functions, beyond homeostatic reflexes. For instance, a recent study demonstrated that the preparation and execution of voluntary actions, as well as its underlying neural activity, are coupled with the breathing cycle. In the current study, we investigated whether such breathing-action coupling is limited to voluntary motor action or whether it is also present for mental actions not (...) involving any overt bodily movement. To answer this question, we recorded electroencephalography (EEG), electromyography (EMG), and respiratory signals while participants were conducting a voluntary action paradigm including self-initiated motor execution (ME), motor imagery (MI), and visual imagery (VI) tasks. We observed that the voluntary initiation of ME, MI, and VI are similarly coupled with the respiration phase. In addition, EEG analysis revealed the existence of readiness potential (RP) waveforms in all three tasks (i.e., ME, MI, VI), as well as a coupling between the RP amplitude and the respiratory phase. Our findings show that the voluntary initiation of both imagined and overt action is coupled with respiration, and further suggest that the breathing system is involved in preparatory processes of voluntary action by contributing to the temporal decision of when to initiate the action plan, regardless of whether this culminates in overt movements. -/- . (shrink)

Motivation: Classical definitions of information, such as the Shannon information, are designed for open loop systems because they define information on a channel which has an input and an output. The main motivation of this paper is to present a closed loop information measure which is compatible with constructivist thinking. Design: Our information measure for a closed loop system reflects how additional sensor inputs are utilised to establish additional sensor-motor loops during learning. Our information measure is based on the (...) assumption that it is not optimal to stay reactive and that it is beneficial to become proactive through increased learning about the environment. Consequently our information measure gauges the utilisation of new sensor inputs to generate anticipatory actions. We call this information measure "predictive information" (PI). Findings: Our PI is zero if the organism uses only its reflex reactions. It grows when the organism is able to use other sensor inputs to preempt reflex reactions and is able to replace reflexes by anticipatory reactions. This has been demonstrated with a real robot that had to learn to avoid obstacles. Conclusion: PI is a new measure which is able to quantify anticipatory learning and, in contrast to the Shannon information, is calculated only at the inputs of an agent. This information measure has been successfully applied to a simple robot task but its application is neither limited to a certain task nor to a certain learning rule. (shrink)

Die Entwicklung der Rationalität ist eine Erfolgsgeschichte. Denn die Rationalität war und ist der Motor der abendländischen Kultur und der Grund dafür, dass sie in der Neuzeit allen anderen Weltkulturen machtpolitisch überlegen ist. Zwischen dem 8. und 6. Jahrhundert v. Chr. formierte sich das logische Denken gleich auf mehreren Feldern: Durch die Erfindung der philosophischen Wissenschaft, die Geometrisierung des Raumes und der Schlachtordnung, die Berechnung der Zeit, durch die Geldwirtschaft und die neuen Organisationsformen des Politischen wurde Rationalität zum Synonym (...) für Fortschritt. Auch die Begriffe Freiheit und Demokratie gehören in diesen Zusammenhang. Silvio Vietta zeichnet diese Erfolgsgeschichte nach, beschreibt aber auch ihre Gefahren und Kurzschlüsse. In der Konsequenz entwickelt er eine : ndere9 aisthetisch rückgebundene und reflexive Rationalität, die uns aus den gegenwärtigen Krisen herausführen könnte. (shrink)

Representational and embodied approaches to cognitive science are often presented in opposition to one another, with Merleau-Ponty serving as a historical precursor to embodied approaches. We argue that the two approaches are compatible and complementary, and that both can be used to interpret Merleau-Ponty's (and Husserl's) work. To support our arguments, we describe two forms of representation associated with two distinct processes. Motor intentionality is a process of direct embodied interaction (reflexes, habits, skilled behaviors) which use mediating representations (...) to bind sensory information together and guide behavior. These internal states reliably indicate specific stimuli (even if just during a transient episode), are associated with a determinate phenomenal character (a “typical physiognomy”), and correspond to what Husserl describes as passive synthesis. Higher-level processes like reasoning make use of more explicit representations (what Husserl calls active processes), which are associated with focused attention and “explicated” propositional contents. The two kinds of process can occur independently, but are often fully woven together, as for example when a friend makes explicit suggestions while the two of you cook. We also discuss Merleau-Ponty’s famous Schneider case, which makes vivid what happens when both types of processes (motor intentionality and high-level reasoning; passive and active synthesis) are intact, but when some explicit representations are damaged. A certain stratum of virtual or projected space is lost, and so a certain kind of abstractly guided behavior is unavailable to him. (shrink)

SummaryProfessor Wallon stresses here the difficulties which have entangled the Study of personality in European countries, because of the subjective and idealistic line of thought which was suggested by philosophers like Descartes, Taine, Bergson, and more recently the existentialists. Their method results in cutting off the solidarity which really exists between the organic and the psychic sides of personality, as also between personality itself and the environment.He then applies these remarks to the special case of emotional behavior, the analysis of (...) which has cost him so much time and work. Contrary to other modes of behavior, which consist in overt movements and aim at modifying the physical world, emotion is an expressive and subject‐moulding process, whereby reacting to à given situation the individual provokes among social partners similar or complementary attitudes.This interaction between the Self and the social milieu, is one of the chief factors which govern the progressive construction of personality. Through alternating identification and opposition, it takes à dialectical character, and shows the essential complementarity of the subject and the environment, contrary to the substantialistic and scholastic view of the past, which, reifying separately these non‐autonomous entities, tried then vainly to reconcile and reunite them.It should be pointed out that, according to Dr Wallon, emotion corresponds to one of the four levels of behavior which progressively appear in the growing child, and form in the adult à hierarchical organisation:1. Impulsive behavior: reflex and automatic actions.2. Emotional behavior.3. Sensori‐motor behavior.4. Projective behavior.More details on these four stages can be found in tome VIII of Encyclopidie francaise, La vie mentale, composed under Dr Wallon's supervision. (shrink)

The implicit activities of the living body in sports (such as heart rate, involuntary gestures, stress, reflex, emotional regulation and interaction expressions) emerge in the consciousness of the lived body without our voluntary control. We demonstrate physiological emersion, and how, including in dramaturgical perception, physiological flows and processes collide with the image of a whole body. In this paper, we introduce corporeal non-property as the missing (?) link between phenomenology and neuroscience, renewed by research on the cerebral unconscious and the (...) perception of their lived body. Rather than mindfulness, physical activity obliges the subject to learn the unconscious and his motor skills from his living body: a new psychoanalysis of sport is thus established by studying what emerges from the activity of the living body up to the level of the conscious description of motor action. In this paper, we explain why that awareness occurs, and why it matters for the understanding of unconscious activity of the athlete’s living body. This is potentially interesting, although it needs, as a theory, to overcome the obvious reliance of the body on unconscious or habitual/automated physiological processes. But the incorporation of body techniques forms a habitus. (shrink)

Most mainstream attempts to understand the “placebo effect” invoke expectancy theory, arguing that expecting certain outcomes from a treatment or intervention can manifest those outcomes. Expectancy theory is incompatible with the phenomena of placebo responses, more appropriately named “meaning responses.” The expectancy account utilizes reflexive consciousness to connect a world of conceptual representations to mechanical physiology. An alternative account based upon Merleau-Ponty's motor intentionality argues that the body understands and is capable of responding to meanings without the need for (...) any conceptual or linguistic content. A motor intentional framework of meaning poses dramatic implications for the interpretation of clinical trials and in the clinical practice of medicine. Most strongly, it argues that the empathic physician can facilitate the physiologic effects of treatments through skillful participation and manipulation of the meaning response. (shrink)

Davon ausgehend, dass Natur und Kultur das gemeinsame Erbe des Menschen bilden, wird dargestellt, was wir unter dem Anthropozän verstehen. Es werden die ungewollten Wirkungen der Industrialisierung und Modernisierung untersucht. Dazu gehören der Klimawandel, die Zerstörung der Biodiversität, die gestörten biogeochemischen Kreisläufe, die Versauerung der Ozeane und die Verschmutzung des Planeten mit der Gefahr der Zerstörung der Lebensgrundlagen der Menschen, Tiere und Pflanzen. Welche Rolle spielen in diesem Prozess die Maschinen? Ohne ihre Erfindung wäre es nicht zu diesem Prozess mit (...) seinen zahlreichen Nebenwirkungen gekommen. Ihre Entwicklung reicht von der Dampfmaschine über die Prothetik bis zur Robotik. Ein wichtiger Motor der Entwicklung sind heute die digitale Kultur und die Künstlichen Intelligenz. Lassen sich diese auch für die nachhaltige Entwicklung nutzen? Ohne die Digitalisierung wäre es nicht zu den Entwicklungen der Gentechnologie gekommen. Mit der Erfindung und Nutzung der CRISPR-Technologie werden Eingriffe in die Evolution möglich, die sich als eine Zuspitzung der Dynamik des Anthropozäns begreifen lassen. Gibt es Möglichkeiten, die Gefährdungen und die negativen Auswirkungen dieser Entwicklungen zu vermeiden oder sie sogar zu kompensieren? Hier entstehen viele nicht einfach beantwortbare anthropologische Fragen, die für ein historisch und kulturell reflexives (Selbst-)Verständnis des Menschen von zentraler Bedeutung sind. (shrink)

In Action in Perception, Alva Noë provides a persuasive account of the “enactive” approach to perception, according to which perception is not simply based on the processing of sensory information, or on the construction of internal representations, but is fundamentally shaped by the motor possibilities of the perceiving body. As John Dewey put it in 1896, in his essay, “The Reflex Arc Concept in Psychology”.

In the Tractatus Russell’s caveat against linguistic reflexivity becomes a caveat against reflective thought. The paper explores the relation between these. There is a connection, perhaps exemplified by 1789, between reflection on one’s assumptions and change. The same connection may be exemplified by violation of Russell’s system of levels. Even though Russell never explored this area, they will be violated by interactions of the macroscopic and microscopic. These interactions, like the philosophical questioning of assumptions, are a source of change and (...) instability, of the failure of assumptions or presuppositions, and with it of aporia. Russell’s system of levels precludes these. An aim of avoiding presupposition failure links type theory to “On Denoting.” It is likely that the resistance to reflexivity has its origin in Russell’s rejection of the philosophy of Hegel where reflective thought is the motor of historical development. (shrink)

Recent work on skin-brain thesis suggests the possibility of empirical evidence that empiricism is false. It implies that early animals need no traditional sensory receptors to be engaged in cognitive activity. The neural structure required to coordinate extensive sheets of contractile tissue for motility provides the starting point for a new multicellular organized form of sensing. Moving a body by muscle contraction provides the basis for a multicellular organization that is sensitive to external surface structure at the scale of the (...) animal body. In other words, the nervous system first evolved for action, not for receiving sensory input. Thus, sensory input is not required for minimal cognition; only action is. The whole body of an organism, in particular its highly specific animal sensorimotor organization, reflects the bodily and environmental spatiotemporal structure. The skin-brain thesis suggests that, in contrast to empiricist claims that cognition is constituted by sensory systems, cognition may be also constituted by action-oriented feedback mechanisms. Instead of positing the reflex arc as the elementary building block of nervous systems, it proposes that endogenous motor activity is crucial for cognitive processes. In the paper, I discuss the issue whether the skin-brain thesis and its supporting evidence can be really used to overthrow the main tenet of empiricism empirically, by pointing out to cognizing agents that fail to have any sensory apparatus. (shrink)

Some patients awaken from their coma but only show reflex motor activity. This condition of wakeful (eyes open) unawareness is called the vegetative state. In 2002, a new clinical entity coined ‘‘minimally conscious state’’ defined patients who show more than reflex responsiveness but remain unable to communicate their thoughts and feelings. Emergence from the minimally conscious state is defined by functional recovery of verbal or nonverbal communication.1 Our empirical medical definitions aim to propose clearcut borders separating disorders of consciousness (...) such as coma, vegetative state and minimally conscious state but clinical reality shows that these boundaries can often be fuzzy (fig 1). Recent clinical, electrophysiological and neuroimaging studies are shedding light on these challenging limits of consciousness encountered following severe acute brain damage. At the patient’s bedside, it is very challenging to differentiate reflex or automatic motor behaviour from movements indicating signs of consciousness, and hence some minimally conscious patients might be misdiagnosed as being vegetative. For some motor responses (eg, blinking to visual threat, brief fixation, normal flexion response to pain, etc) it remains unclear whether they truly are voluntary or willed because we lack convincing scientific evidence. We also lack consensus on how to practically assess some of these behavioural responses. For example, there is no agreement on what stimulus to employ in the assessment of visual pursuit movements— often one of the first clinical signs heralding the transition from the vegetative to the minimally conscious state. Vanhaudenhuyse and colleagues2 recently studied visual pursuit in 51 post-comatose patients comparing eye tracking of a moving object, person or mirror. It was shown that more.. (shrink)

The target article discusses various aspects of the relationship between the sympathetic system and pain. To this end, the patients under study are divided into three groups. In the first group, called (RSD), the syndrome can be characterized by a triad of autonomic, motor, and sensory symptoms, which occur in a distally generalized distribution. The pain is typically felt deeply and diffusely, has an orthostatic component, and is suppressed by the ischemia test. Under those circumstances, the pain is likely (...) to respond to sympatholytic interventions. In a second group, called (SMP) syndrome, the principal symptoms are spontaneous pain, which is felt superficially and has no orthostatic component, and allodynia. These symptoms, typically confined to the zone of a lesioned nerve, may also be relieved by sympathetic blocks. Since the characteristics of the pain differ between RSD and SMP, the underlying kind of sympathetic–sensory coupling may also vary between these cases. A very small third group of patients exhibits symptoms of both RSD and SMP. The dependence or independence of pain on sympathetic function reported in most published studies seems to be questionable because the degree of technical success of the block remains uncertain. Therefore, pain should not be reported as sympathetic function independent until the criteria for a complete sympathetic block have been established and satisfied. (shrink)