We outline some ways in which motor neglect (the underutilization of a limb despite adequate strength) and hysterical paralysis (failure to move a limb despite no relevant structural damage or disease) may throw light on the pathophysiology of catatonia. We also comment on the manifold inadequacies of distinguishing too firmly between symptoms of “neurologic origin” and of “psychiatric origin.”.

What triggers the execution of actions? What happens in that moment when an action is triggered? What mental state is there at the moment of action-execution that was not there a second before? My aim is to highlight the importance of a thus far largely ignored kind of mental state in the discussion of these old and much-debated questions: motor imagery. While there have been a fair amount of research in psychology and neuroscience on motor imagery in the (...) last 30 years or so, it is only recently that we start to understand the important role motor imagery plays in action initiation. And if, as these findings suggest, motor imagery plays an important role in action initiation, we can make progress not only in understanding action initiation in general but also in understanding what goes wrong in akratic actions and in relapse actions. Finally, this new picture of action-initiation also has far-reaching consequences for the relation between motivation and causation in naturalistic action-explanations. (shrink)

What are the most detailed descriptions under which subjects intend to perform bodily actions? According to Pacherie (2006), these descriptions may be found by looking into motor representations—action representations in the brain that determine the movements to be performed. Specifically, for any motor representation guiding an action, its subject has an M‐intention representing that action in as much detail. I show that some M‐intentions breach the constraints that intentions should meet. I then identify a set of intentions—motor (...) intentions—that represent actions in as much detail as some motor representations while meeting the constraints that intentions should meet. (shrink)

I argue that Merleau-Ponty’s use of the case of Schneider in his arguments for the existence of non-conconceptual and non-representational motor intentionality contains a problematic methodological ambiguity. Motor intentionality is both to be revealed by its perspicuous preservation and by its contrastive impairment in one and the same case. To resolve the resulting contradiction I suggest we emphasize the second of Merleau-Ponty’s two lines of argument. I argue that this interpretation is the one in best accordance both with (...) Merleau-Ponty’s general methodology and with the empirical case of Schneider as it was described by Gelb and Goldstein. (shrink)

There is a long‐standing project in psychology the goal of which is to explain our ability to perceive speech. The project is motivated by evidence that seems to indicate that the cognitive processing to which speech sounds are subjected is somehow different from the normal processing employed in hearing. The Motor Theory of speech perception was proposed in the 1960s as an attempt to explain this specialness. The first part of this essay is concerned with the Motor Theory's (...) explanandum. It shows that it is rather hard to give a precise account of what the Motor Theory is a theory of. The second part of the essay identifies problems with the theory's explanans: There are difficulties in finding a plausible account of what the content of the Motor Theory is supposed to be. (shrink)

Our ability to acknowledge and recognise our own identity - our 'self' - is a characteristic doubtless unique to humans. Where does this feeling come from? How does the combination of neurophysiological processes coupled with our interaction with the outside world construct this coherent identity? We know that our social interactions contribute via the eyes, ears etc. However, our self is not only influenced by our senses. It is also influenced by the actions we perform and those we see others (...) perform. Our brain anticipates the effects of our own actions and simulates the actions of others. In this way, we become able to understand ourselves and to understand the actions and emotions of others. -/- This book is the first to describe the new field of 'Motor Cognition' - one to which the author's contribution has been seminal. Though motor actions have long been studied by neuroscientists and physiologists, it is only recently that scientists have considered the role of actions in building the self. How consciousness of action is part of self-consciousness, how one's own actions determine the sense of being an agent, how actions performed by others impact on ourselves for understanding others, differentiating ourselves from them and learning from them: these questions are raised and discussed throughout the book, drawing on experimental, clinical, and theoretical bases. -/- The advent of new neuroscience techniques, like neuroimaging and direct electrical brain stimulation, together with a renewal of behavioral methods in cognitive psychology, provide new insights into this area. Mental imagery of action, self-recognition, consciousness of actions, imitation can be objectively studied using these new tools. The results of these investigations shed light on clinical disorders in neurology, psychiatry and in neuro-development. -/- This is a major new work that will lay down the foundations for the field of motor cognition. (shrink)

A full account of purposive action must appeal not only to propositional attitude states like beliefs, desires, and intentions, but also to motor representations, i.e., non-propositional states that are thought to represent, among other things, action outcomes as well as detailed kinematic features of bodily movements. This raises the puzzle of how it is that these two distinct types of state successfully coordinate. We examine this so-called “Interface Problem”. First, we clarify and expand on the nature and role of (...) motor representations in explaining intentional action. Next, we characterize the respective functions of intentions and motor representations, the differences in representational format and content that these imply, and the interface challenge these differences in turn raise. We then evaluate Butterfill and Sinigaglia’s recent answer to this interface challenge, according to which intentions refer to action outcomes by way of demonstrative deference to motor representations. We present some worries for this proposal, arguing that, among other things, it implicitly presupposes a solution to the problem, and so cannot help to resolve it. Finally, we suggest that we may make some progress on this puzzle by positing a “content-preserving causal process” taking place between intentions and motor representations, and we offer a proposal for how this might work. (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 control of action has traditionally been described as "automatic". In particular, movement control may occur without conscious awareness, in contrast to normal visual perception. Studies on rapid visuomotor adjustment of reaching movements following a target shift have played a large part in introducing such distinctions. We suggest that previous studies of the relation between motor performance and perceptual awareness have confounded two separate dissociations. These are: (a) the distinction between motoric and perceptual representations, and (b) an orthogonal distinction (...) between conscious and unconscious processes. To articulate these differences more clearly, we propose a new measure of motor awareness, based on subjects' ability to reproduce the spatial details of reaching movements they have just made. Here we focus on the dissociation between motor awareness and perceptual awareness that may occur when subjects make rapid visuomotor adjustments to reaching movements following a target shift. In experiment 1, motor awareness was dissociated from perceptual awareness of a target shift during reaching movement. Participants' reproduction of movement endpoints following visuomotor adjustment was independent of whether they saw the target shift or not. Experiment 2 replicated this result, and further showed that neither motor awareness nor motor performance were disrupted by TMS over the parietal cortex. The neural mechanisms underlying motor awareness, and the implications for theories of consciousness, are discussed. (shrink)

Recent advances in the cognitive neuroscience of action have considerably enlarged our understanding of human motor cognition. In particular, the activity of the mirror system, first discovered in the brain of non-human primates, provides an observer with the understanding of a perceived action by means of the motor simulation of the agent's observed movements. This discovery has raised the prospects of a motor theory of social cognition. Since human social cognition includes the ability to mindread, many (...) class='Hi'>motor theorists of social cognition try to bridge the gap between motor cognition and mindreading by endorsing a simulation account of mindreading. Here, we express our skepticism about the motor theory of social cognition. (shrink)

Maurice Merleau-Ponty is often interpreted as claiming that opportunities for action are directly present in perceptual experience. However, he does not provide much evidence for how or why this would occur, and one can doubt that this is an appropriate interpretation of his phenomenological descriptions. In particular, it could be argued the Merleau-Pontyian descriptions mistakenly attribute pre-perceptual or post-perceptual elements such as allocation of attention or judgment to the perceptual experience itself. This paper argues for the Merleau-Pontyian idea that opportunities (...) for action are present in perceptual experience. It further argues that the phenomenological descriptions can be supported and explained via reference to contemporary research on motor imagery. In particular, it will be argued that non-conscious, covert motor imagery is used to prepare for and regulate skilled actions, and that it is plausible that this imagery combines with perception (likely vision) to create a single experience of the environment as enabling action. The paper will also show that contemporary views on motor imagery are broadly compatible with Merleau-Ponty’s aims. (shrink)

& The functional equivalence of overt movements and dynamic imagery is of fundamental importance in neuroscience. Here, we investigated the participation of the neocortical motor areas in a classic task of dynamic imagery, Shepard and Metzler's mental rotation task, by time-resolved single-trial functional Magnetic Resonance Imaging (fMRI). The subjects performed the mental-rotation task 16 times, each time with different object pairs. Functional images were acquired for each pair separately, and the onset times and..

People walk, build, paint and otherwise act together with a purpose in myriad ways. What is the relation between the actions people perform in acting together with a purpose and the outcome, or outcomes, to which their actions are directed? We argue that fully characterising this relation will require appeal not only to intention, knowledge and other familiar philosophical paraphernalia but also to another kind of representation involved in preparing and executing actions, namely motor representation. If we are right, (...) motor representation plays a central role in the story of acting together. (shrink)

Much indirect evidence supports the hypothesis that transformations of mental images are at least in part guided by motor processes, even in the case of images of abstract objects rather than of body parts. For example, rotation may be guided by processes that also prime one to see results of a specific motor action. We directly test the hypothesis by means of a dual-task paradigm in which subjects perform the Cooper-Shepard mental rotation task while executing an unseen (...) class='Hi'>motor rotation in a given direction and at a previously learned speed. Four results support the inference that mental rotation relies on motor processes. First, motor rotation that is compatible with mental rotation results in faster times and fewer errors in the imagery task than when the two rotations are incompatible. Second, the angle through which subjects rotate their mental images, and the angle through which they rotate a joystick handle are correlated, but only if the directions of the two rotations are compatible. Third, motor rotation modifies the classical inverted V-shaped mental rotation response time function, favoring the direction of the motor rotation; indeed, in some cases motor rotation even shifts the location of the minimum of this curve in the direction of the motor rotation. Fourth, the preceding effect is sensitive not only to the direction of the motor rotation, but also to the motor speed. A change in the speed of motor rotation can correspondingly slow down or speed up the mental rotation. (shrink)

Dynamic stability of the knee and weakness of the extensor muscles are considered to be the most important functional limitations after anterior cruciate ligament injury, probably due to changes at the central level of motor control rather than at the peripheral level. Despite general technological advances, fewer contraindicative surgical procedures, and extensive postoperative rehabilitation, up to 65% of patients fail to return to their preinjury level of sports, and only half were able to return to competitive sport. Later, it (...) becomes clear that current rehabilitation after knee surgery is not sufficient to address the functional limitations after ACL reconstruction even years after surgery. Therefore, new therapeutic tools targeting the central neural system, i.e., the higher centers of motor control, should be investigated and integrated into current rehabilitation practice. To improve motor performance when overt movement cannot be fully performed, several techniques have been developed to increase physical and mental activation without the need to perform overt movements. Among the most popular cognitive techniques used to increase physical performance are motor imagery and action observation practices. This review, which examines the available evidence, presents the underlying mechanisms of the efficacy of cognitive interventions and provides guidelines for their use at home. (shrink)