Recent computational models of motor planning have relied heavily on anticipating the consequences of motor acts. Such anticipation is vital for dealing with the redundancy problem of motor control (i.e., the problem of selecting a particular motor solution when more than one is possible to achieve a goal). Computational approaches to motor planning support the Theory of Event Coding (TEC).

Vaesen asks whether goal maintenance and planning ahead are critical for innovative tool use. We suggest that these aptitudes may have an evolutionary foundation in motor planning abilities that span all primate species. Anticipatory effects evidenced in the reaching behaviors of lemurs, tamarins, and rhesus monkeys similarly bear on the evolutionary origins of foresight as it pertains to tool use.

New experimental evidence throws doubt on postulating no relationship between saccade control and visual object recognition. The control of saccades during reading depends on the perceptual system mediating object recognition.

Experimental studies of speech production involving compensations for auditory and somatosensory perturbations and adaptation after training suggest that both types of sensory information are considered to plan and monitor speech production. Interestingly, individual sensory preferences have been observed in this context: subjects who compensate less for somatosensory perturbations compensate more for auditory perturbations, and \textit{vice versa}. We propose to integrate this sensory preference phenomenon in a model of speech motor planning using a probabilistic model in which speech units (...) are characterized both in auditory and somatosensory terms. Sensory preference is implemented in the model according to two approaches. In the first approach, which is often used in motor control models accounting for sensory integration, sensory preference is attributed to the relative precision (i.e., inverse of the variance) of the sensory characterization of the speech motor goals associated with phonological units (which are phonemes in the context of this paper). In the second, ``more original’’ variant, sensory preference is implemented by modulating the sensitivity of the comparison between the predicted sensory consequences of motor commands and the sensory characterizations of the phonemes. We present simulation results using these two variants, in the context of the adaptation to an auditory perturbation, implemented in a 2-dimensional biomechanical model of the tongue. Simulation results show that both variants lead to qualitatively similar results. Distinguishing them experimentally would require precise analyses of partial compensation patterns. However, the second proposed variant implements sensory preference without changing the sensory characterizations of the phonemes. This dissociates sensory preference and sensory characterizations of the phonemes, and makes the account of sensory preference more flexible. Indeed, in the second variant the sensory characterizations of the phonemes can remain stable, when sensory preference varies as a response to cognitive or attentional control. This opens new perspectives for capturing speech production variability associated with aging, disorders and speaking conditions. (shrink)

A broad sketch for a model of speech production is outlined which describes developmental aspects of its cognitive-linguistic and sensorimotor components. A description of the emergence of phonological knowledge is a central point in our model sketch. It will be shown that the phonological form level emerges during speech acquisition and becomes an important representation at the interface between cognitive-linguistic and sensorimotor processes. Motor planning as well as motor programming are defined as separate processes in our model (...) sketch and it will be shown that both processes revert to the phonological information. Two computational simulation experiments based on quantitative implementations are undertaken to show proof of principle of key ideas of the model sketch: the emergence of phonological information over developmental stages, the adaptation process for generating new motor programs, and the importance of various forms of phonological representation in that process. Based on the ideas developed within our sketch of a production model and its quantitative spell-out within the simulation models, motor planning can be defined here as the process of identifying a succession of executable chunks from a currently activated phoneme sequence and of coding them as raw gesture scores. Motor programming can be defined as the process of building up the complete set of motor commands by specifying all gestures in detail. This full specification of gesture scores is achieved in our model by adapting motor information from phonologically similar syllables or by assembling motor programs from sub-syllabic units. (shrink)

In dynamical systems models feedforward is needed to guide planning and to process unknown and unpredictable events. Feedforward could help Theory of Event Coding (TEC) integrate control processes and could model human performance in action planning in a more flexible and powerful way.

Glover's planning–control model accommodates a substantial number of findings from subjects who have motor deficits as a consequence of brain lesions. A number of consistently observed and robust findings are not, however, explained by Glover's theory; additionally, the claim that the IPL supports planning whereas the SPL supports control is not consistently supported in the literature.

The ultimate tool, it could be said, is the brain and body. Therefore, a way to understand tool use is to study the brain's control of the body. A more manageable aim is to use the tools of cognitive science to explore the planning of physical actions. Here, I focus on two kinds of physical acts which directly or indirectly involve tool use: producing finger‐press sequences, and walking and reaching for objects. The main question is how people make choices (...) between finger‐press sequences, and how people make choices between walk‐and‐reach sequences. Are the choices made with reference to motor imagery, in which case the longer the sequences are the longer it takes to choose between them, or are shortcuts taken which rely on distinctive features of the alternatives? The reviewed experiments favor the latter alternative. The general view of action planning emerging from this work is one in which action features are highlighted and held in memory, not just to choose between potential actions but also to control the unfolding of long actions over time. Speculations are offered about tool use. (shrink)

Many activities of daily living require that we physically interact with one or more objects. Object manipulation provides an intriguing domain in which the presence and extent of manual asymmetries can be studied on a motor planning and a motor execution level. In this literature review we present a state of the art for manual asymmetries at the level of motor planning during object manipulation. First, we introduce pioneering work on grasp posture planning. We (...) then sketch the studies investigating the impact of future task demands during unimanual and bimanual object manipulation tasks in healthy adult populations. In sum, in contrast to motor execution, there is little evidence for hand-based performance differences in grasp posture planning. We discuss potential reasons for the lack of manual asymmetries in motor planning and outline potential avenues of future research. (shrink)

Evidence from optic ataxic patients with bilateral lesions to the superior parietal lobes does not support the view that there are separate planning and control mechanisms located in the IPL and SPL respectively. The aberrant reaches of patients with bilateral SPL damage towards extrafoveal targets seem to suggest a deficit in the selection of appropriate motor programmes rather than a deficit restricted to on-line control.

Several arguments suggest that motor planning may share embodied neural mechanisms with mental rotation (MR). However, it is not well established whether this overlap occurs regardless of the type of stimulus that is manipulated, in particular manipulable or non-manipulable objects and body parts. We here used high-density electroencephalography (EEG) to examine the cognitive similarity between MR of objects that do not afford specific hand actions (chairs) and bodily stimuli (hands). Participants had identical response options for both types of (...) stimuli, and they gave responses orally in order to prevent possible interference with motor imagery. MR of hands and chairs generated very similar behavioral responses, time-courses and neural sources of evoked-response potentials (ERPs). ERP segmentation analysis revealed distinct time windows during which differential effects of stimulus type and angular disparity were observed. An early period (90–160 ms) differentiated only between stimulus types, and was associated with occipito-temporal activity. A later period (290–330 ms) revealed strong effects of angular disparity, associated with electrical sources in the right angular gyrus and primary motor/somatosensory cortex. These data suggest that spatial transformation processes and motor planning are recruited simultaneously, supporting the involvement of motor emulation processes in MR. (shrink)

The human masticatory system is a complex functional unit characterized by a multitude of skeletal components, muscles, soft tissues, and teeth. Muscle activation dynamics cannot be directly measured on live human subjects due to ethical, safety, and accessibility limitations. Therefore, estimation of muscle activations and their resultant forces is a longstanding and active area of research. Reinforcement learning (RL) is an adaptive learning strategy which is inspired by the behavioral psychology and enables an agent to learn the dynamics of an (...) unknown system via policy-driven explorations. The RL framework is a well-formulated closed-loop system where high capacity neural networks are trained with the feedback mechanism of rewards to learn relatively complex actuation patterns. In this work, we are building on a deep RL algorithm, known as the Soft Actor-Critic, to learn the inverse dynamics of a simulated masticatory system, i.e., learn the activation patterns that drive the jaw to its desired location. The outcome of the proposed training procedure is a parametric neural model which acts as the brain of the biomechanical system. We demonstrate the model’s ability to navigate the feasible three-dimensional (3D) envelope of motion with sub-millimeter accuracies. We also introduce a performance analysis platform consisting of a set of quantitative metrics to assess the functionalities of a given simulated masticatory system. This platform assesses the range of motion, metabolic efficiency, the agility of motion, the symmetry of activations, and the accuracy of reaching the desired target positions. We demonstrate how the model learns more metabolically efficient policies by integrating a force regularization term in the RL reward. We also demonstrate the inverse correlation between the metabolic efficiency of the models and their agility and range of motion. The presented masticatory model and the proposed RL training mechanism are valuable tools for the analysis of mastication and other biomechanical systems. We see this framework’s potential in facilitating the functional analyses aspects of surgical treatment planning and predicting the rehabilitation performance in post-operative subjects. (shrink)

This study explored the effect of kinesthetic motor imagery training on reaching-to-grasp movement supplemented by a virtual environment in a patient with congenital bilateral transverse upper-limb deficiency. Based on a theoretical assumption, it is possible to conduct such training in this patient. The aim of this study was to evaluate whether cortical activity related to motor imagery of reaching and motor imagery of grasping of the right upper limb was changed by computer-aided imagery training in a patient (...) who was born without upper limbs compared to a healthy control subject, as characterized by multi-channel electroencephalography signals recorded before and 4, 8, and 12 weeks after CAIT. The main task during CAIT was to kinesthetically imagine the execution of reaching-to-grasp movements without any muscle activation, supplemented by computer visualization of movements provided by a special headset. Our experiment showed that CAIT can be conducted in the patient with higher vividness of imagery for reaching than grasping tasks. Our results confirm that CAIT can change brain activation patterns in areas related to motor planning and the execution of reaching and grasping movements, and that the effect was more pronounced in the patient than in the healthy control subject. The results show that CAIT has a different effect on the cortical activity related to the motor imagery of a reaching task than on the cortical activity related to the motor imagery of a grasping task. The change observed in the activation patterns could indicate CAIT-induced neuroplasticity, which could potentially be useful in rehabilitation or brain-computer interface purposes for such patients, especially before and after transplantation. This study was part of a registered experiment. (shrink)

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in (...) parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language. Key Words: efference copies; emulation theory of representation; forward models; Kalman filters; motor control; motor imagery; perception; visual imagery. (shrink)

We examined the role of verbal mediation in planning performance of English–Spanish-speaking bilingual children and monolingual English-speaking children, between the ages of 9 and 12 years. To measure planning, children were administered the Tower of London (ToL) task. In a dual-task paradigm, children completed ToL problems under three conditions: with no secondary task (baseline), with articulatory suppression, and with non-verbal motor suppression. Analyses revealed generally shorter planning times for bilinguals than monolinguals but both groups performed similarly (...) on number of moves and execution times. Additionally, bilingual children were more efficient at planning throughout the duration of the task while monolingual children showed significant gains with more practice. Children’s planning times under articulatory suppression were significantly shorter than under motor suppression as well as the baseline condition, and there was no difference in planning times between monolingual and bilingual children during articulatory suppression. These results demonstrate that bilingualism influences performance on a complex EF measure like planning, and that these effects are not related to verbal mediation. (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)

The processes underlying motor decision-making have recently caught considerable amount of scientific attention, focusing on the integration of empirical evidence from sensorimotor control research with psychological theories and computational models on decision-making. Empirical studies on motor decision-making suggest that the kinematics of goal-directed reaching movements are sensitive to the level of target uncertainty during movement planning. However, the source of uncertainty as a relevant factor influencing the process of motor decision-making has not been sufficiently considered, yet. (...) In this study, we test the assumption that the source of target uncertainty has an effect on motor decision-making, which can be proven by analyzing movement variability during the time course of movement execution. Ten healthy young adults performed three blocks with 66 trials of goal-directed reaching movements in each block, across which the source and level of reach target uncertainty at movement onset were manipulated (“no uncertainty”, “extrinsic uncertainty”, “intrinsic uncertainty”). Fingertip position of the right index finger was recorded using an optical motion tracking system. Standard kinematic measures (i.e. path length and movement duration) as well as variability of fingertip position across the time course of movement execution and at movement end were analyzed. In line with previous studies, we found that a high level of extrinsic target uncertainty leads to increased overall movement duration, which could be attributed to increased path length in this condition, as compared to intrinsic and no target uncertainty (all p <.001). Movement duration and path length did not show any differences between the latter two conditions. However, the time course analysis of movement variability revealed significant differences between these two conditions, with increased variability of fingertip position in the presence of intrinsic target uncertainty (Condition × Sampling point: p =.01), though considerably less than under high extrinsic target uncertainty (p ≤.001). These findings suggest that both the level and source of uncertainty have a significant effect on the processing of potential action plans during motor decision-making, which can be revealed through the analysis of the time course of movement variability at the end-effector level. (shrink)

The intentionality of improvisation represents surely one of the most pressing and controversial issues in contemporary action theory: how do we find the way to characterize the proper intentionality of improvisation, which is an unplanned yet intentional action? This article will address this question bringing together Merleau-Ponty’s motor intentionality and Bergson’s conception of duration. My argument will unfold in three main stages. First, I will briefly describe the traditional scheme that is used to think of intentional action in contemporary (...) action theory and discuss how the phenomenon of improvisation casts doubts on it. Second, I will outline an initial, and provisional account of improvisation by crossing the descriptions of musical improvisation provided by Jankélévitch with the testimonials of two improvisatory composers—Enrico Pieranunzi and Keith Jarrett—and reports from Charles Rosen, an American pianist and Roger Sessions, an American composer. Finally, I will refine the basic concepts and lay out a phenomenological account of improvisation, by extending and applying the phenomenological notion of motor intentionality to the examples and testimonials gathered from the observation of a specific kind of improvisatory activity—musical composition. This methodology is intended to contrast both with more standard philosophical approaches based on hypothetical examples, and with more standard laboratory-based methodologies in cognitive sciences, psychology, and experimental philosophy. Overall, this approach is intended to redress the balance of action theory—one-sided directed towards planning, as a key aspect of human agency—with an analysis of the bodily and responsive aspect of intentionality. (shrink)

The invariant left–right asymmetry of animal body plans raises fascinating questions in cell, developmental, evolutionary, and neuro‐biology. While intermediate mechanisms (e.g., asymmetric gene expression) have been well‐characterized, very early steps remain elusive. Recent studies suggested a candidate for the origins of asymmetry: rotary movement of extracellular morphogens by cilia during gastrulation. This model is intellectually satisfying, because it bootstraps asymmetry from the intrinsic biochemical chirality of cilia. However, conceptual and practical problems remain with this hypothesis, and the genetic data is (...) consistent with a different mechanism. Based on wide‐ranging data on ion fluxes and motor protein action in a number of species, a model is proposed whereby laterality is generated much earlier, by asymmetric transport of ions, which results in pH/voltage gradients across the midline. These asymmetries are in turn generated by a new candidate for “step 1”: asymmetric localization of electrogenic proteins by cytoplasmic motors. BioEssays 25:1002–1010, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

The concept of voluntary motor control(VMC) frequently appears in the neuroscientific literature, specifically in the context of cortically-mediated, intentional motor actions. For cognitive scientists, this concept of VMC raises a number of interesting questions:(i) Are there dedicated, modular-like structures within the motor system associated with VMC? Or (ii) is it the case that VMC is distributed over multiple cortical as well as subcortical structures?(iii) Is there any one place within the so-calledhierarchy of motor control where voluntary (...) movements could be said to originate? And (iv) in the current neurological literature how is the adjective voluntary in VMC being used? These questions are here considered in the context of how higher- and lower-levels of motor control, plan, initiate, coordinate, sequence, and modulate goal-directed motor outputs in response to changing internal and external inputs. Particularly relevant are the conceptual implications of current neurological modeling of VMC concerning causal agency. (shrink)

Actions shape what we see and memorize. A previous study suggested the interaction between motor and memory systems by showing that memory encoding for task-irrelevant items was enhanced when presented with motor-response cues. However, in the studies on the attentional boost effect, it has been revealed that detection of the target stimulus can lead to memory enhancement without requiring overt action. Thus, the direct link between the action and memory remains unclear. To exclude the effect of the target (...) detection process as a potential confounder, this study assessed the benefit of action for memory by separating items from the response cue in time. In our pre-registered online experiment, participants responded to visual Go cues by pressing a key or counting while ignoring No-go cues. In each trial, two task-irrelevant images were sequentially presented after the cue disappearance. After encoding the Go/No-go tasks, participants performed a surprise recognition memory test for those images. Importantly, we quantified the impact of overt execution of the action by comparing memories with and without motor response and the impact of covert motor processes by comparing memory between the motor and cognitive tasks. The results showed no memory differences between Go and No-go trials in the motor task. This means that the execution itself was not critical for memory enhancement. However, the memory performance in the motor No-go trials was higher than that in the cognitive No-go trials, only for the items presented away from the cues in time. Therefore, engaging the motor task itself could increase incidental memory for the task-irrelevant items compared to a passive viewing situation. We added empirical evidence on the online interaction between action and memory encoding. These memory advantages could be especially brought in action preparation and planning. We believe this fact may expand our present understanding of everyday memory, such as active learning. (shrink)

Autism spectrum disorders (ASD) are thought to result in part from altered cortical excitatory-inhibitory balance; this pathophysiology may impact the generation of oscillations on EEG. We investigated premotor-parietal cortical physiology associated with praxis, which has strong theoretical and empirical associations with ASD symptomatology. 25 children with high-functioning ASD (HFA) and 33 controls performed a praxis task involving the pantomiming of tool use, while EEG was recorded. We assessed task-related modulation of signal power in alpha and beta frequency bands. Compared with (...) controls, subjects with HFA showed 27% less left central (motor/premotor) beta (18-22 Hz) event-related desynchronization (ERD) (p = 0.030), as well as 24% less left parietal alpha (7-13 Hz) ERD (p = 0.046). Within the HFA group, blunting of central ERD attenuation was associated with impairments in clinical measures of praxis imitation (r = -0.4; p = 0.04) and increased autism severity (r = 0.48; p = 0.016). The modulation of central beta activity is associated, among other things, with motor imagery, which may be necessary for imitation. Impaired imitation has been associated with core features of ASD. Altered modulation of oscillatory activity may be mechanistically involved in those aspects of motor network function that relate to the core symptoms of ASD. (shrink)

Brindley proposed that we initially generate movements , under higher cerebral control. As the movement is practiced, the cerebellum learns to link within itself the context in which the movement is made to the lower level movement generators. Marr and Albus proposed that the linkage is established by a special input from the inferior olive, which plays upon an input-output element within the cerebellum during the period of the learning. When the linkage is complete, the occurrence of the context (represented (...) by a certain input to the cerebellum) will trigger (through the cerebellum) the appropriate motor response. The movement is distinguished from the conscious movement by its now being automatic, rapid, and stereotyped. The idea is still controversial, but has been supported by a variety of animal studies and, as reviewed here, is consistent with the results of a number of human PET and ablation studies. I have added to the idea of context-response linkage what I think is another important variable: novel combinations of downstream elements. With regard to the motor system and the muscles, this could explain how varied combinations of muscles may become active in precise time-amplitude specifications so as to produce coordinated movements appropriate to specific contexts. In this target article, I have further extended this idea to the premotor parts of the brain and their role in cognition. These areas receive influences from the cerebellum; they are active both in planning movements that are to be executed and in thinking about movements that are not to be executed. From recent evidence, the cerebellar output extends even to what has been characterized as the ultimate frontal planning area, the cortex, area 46. The cerebellum thus may be involved in context-response linkage, and response combination even at these higher levels. The implication would be that, through practice, an experiential context would automatically evoke a certain mental action plan. The plan would be in the realm of thought, and could lead to execution. The specific cerebellar contribution would be one of the context linkage and the shaping of the response, through trial and error learning. The prefrontal and premotor areas could still plan without the help of the cerebellum, but not so automatically, rapidly, stereotypically, so precisely linked to context, or so free of error. Nor would their activities improve optimally with mental practice. (shrink)

Non-local phonological patterns can be difficult to analyze in the context of speech production models. Some patterns – e.g., vowel harmonies, nasal harmonies – can be readily analyzed to arise from temporal extension of articulatory gestures (i.e., spreading); such patterns can be viewed as articulatorily local. However, there are other patterns – e.g., nasal consonant harmony, laryngeal feature harmony – which cannot be analyzed as spreading; instead these patterns appear to enforce agreement between features of similar segments without affecting intervening (...) segments. Indeed, there are numerous typological differences between spreading harmonies and agreement harmonies, and this suggests that there is a mechanistic difference in the ways that spreading and agreement harmonies arise. This paper argues that in order to properly understand spreading and agreement patterns, the gestural framework of Articulatory Phonology must be enriched with respect to how targets of the vocal tract are controlled in planning and production. Specifically, it is proposed that production models should distinguish between excitatory and inhibitory articulatory gestures, and that gestures which are below a selection threshold can influence the state of the vocal tract, despite not being active. These ideas are motivated by several empirical phenomena, which include anticipatory posturing before production of a word form, and dissimilatory interactions in distractor-target response paradigms. Based on these ideas, a model is developed which provides two distinct mechanisms for the emergence of non-local phonological patterns. (shrink)

Several canonical experimental paradigms (e.g., serial reaction time task, discrete sequence production task,m×ntask) have been proposed to study the typical behavioral phenomenon and the nature of learning in sequential keypress tasks. A characteristic feature of most paradigms is that they are representative ofexternally-specifiedsequencing—motor tasks where the environment or task paradigm extrinsically provides the sequence of stimuli, i.e., the responses are stimulus-driven. Previous studies utilizing such canonical paradigms have largely overlooked the learning behaviors in a more realistic class of (...) class='Hi'>motor tasks that involveinternally-guidedsequencing—where the sequence of motor actions is self-generated or internally-specified. In this work, we use the grid-navigation task as an instance of internally-guided sequencing to investigate the nature of learning in such paradigms. The participants performed Grid-Sailing Task (GST), which required navigating (by executing sequential keypresses) a 5 × 5 grid from start to goal (SG) position while using a particular key-mapping (KM) among the three cursor-movement directions and the three keyboard buttons. The participants performed two behavioral experiments—Single-SG and Mixed-SG condition. The Single-SG condition required performing GST on a single SG position repeatedly, whereas the Mixed-SG condition involved performing GST using the same KM on two novel SG positions presented in a random, inter-mixed manner. In the Single-SG condition, we show that motor learning contributes to the sequence-specific learning in GST with the repeated execution of the same trajectories. In the Mixed-SG condition, since the participants utilize the previously learned KM, we anticipate a transfer of learning from the Single-SG condition. The acquisition and transfer of a KM-specific internal model facilitates efficient trajectory planning on novel SG conditions. The acquisition of such a KM-specific internal model amounts to trajectory-independent cognitive learning in GST. We show that cognitive learning contributes to the learning in GST by showing transfer-related performance improvements in the Mixed-SG condition. In sum, we show the role of cognitive and motor learning processes in internally-guided sequencing and further make a case for using GST-like grid-navigation paradigms in investigating internally guided skill learning. (shrink)

I intend to show some of the limits of the decision-theoretic model in connection with the analysis of cognitive agency. Although the concept of maximum expected utility can be helpful for explaining the decision-making process, it is certainly not the primary motor that moves agents to action. Moreover, it has been noticed elsewhere that this model is inadequate to the analysis of single cases of practical reasoning. A theory is proposed that introduces a plan-structure as a basic idea. In (...) order to know its very conceptual scope, we need to accommodate that theory to a cognitive architecture whereby the rational and autonomous agent makes choices and deliberates between courses of action to achieve specific goals that are of its interest. The paper endeavours also to clarify the relationship between the different modules that should constitute the architecture of an agent to accomplish the requisites of efficiency and autonomy in a changeable and dynamic world. (shrink)

Consistent with the planning–control model, recent fMRI data reveal that the inferior parietal lobe, the frontal lobes, and the basal ganglia are involved in motor planning. Inconsistent with the planning–control model, however, recent behavioral data reveal a spatial repulsion effect, indicating that the visual context surrounding the target can sometimes influence the on-line control of goal-directed action.

Intelligible speakers achieve specific vocal tract constrictions in rapid sequence. These constrictions are associated in theory with speech motor goals. Adult-focused models of speech production assume that discrete phonological representations, sequenced into word-length plans for output, define these goals. This assumption introduces a serial order problem for speech. It is also at odds with children's speech. In particular, child phonology and timing control suggest holistic speech plans, and so the hypothesis of whole word production. This hypothesis solves the serial (...) order problem by avoiding it. When the same solution is applied to adult speech the problem becomes how to explain the development of highly intelligible speech. This is the problem addressed here. A modeling approach is used to demonstrate how perceptual-motor units of production emerge over developmental time with the perceptual-motor integration of holistic speech plans that are also phonological representations; the specific argument is that perceptual-motor units are a product of trajectories (nearly) crossing in motor space. The model, which focuses on the integration process, defines the perceptual-motor map as a set of linked pairs of experienced perceptual and motor trajectories. The trajectories are time-based excursions through speaker-defined perceptual and motor spaces. By hypothesis, junctures appear where motor trajectories near or overlap one another in motor space when the shared (or extremely similar) articulatory configurations in these regions are exploited to combine perceptually-linked motor paths along different trajectories. Junctures form in clusters in motor space. These clusters, along with their corresponding (linked) perceptual points, represent perceptual-motor units of production, albeit at the level of speech motor control only. The units serve as pivots in motor space during speaking; they are points of transition from one motor trajectory to another along perceptually-linked paths that are selected to produce best approximations of whole word targets. (shrink)

Current models of speech motor control rely on either trajectory-based control (DIVA, GEPPETO, ACT) or a dynamical systems approach based on feedback control (Task Dynamics, FACTS). While both approaches have provided insights into the speech motor system, it is difficult to connect these findings across models given the distinct theoretical and computational bases of the two approaches. We propose a new extension of the most widely used dynamical systems approach, Task Dynamics, that incorporates many of the strengths of (...) trajectory-based approaches, providing a way to bridge the theoretical divide between what have been two separate approaches to understanding speech motor control. The Task Dynamics (TD) model posits that speech gestures are governed by point attractor dynamics consistent with a critically damped harmonic oscillator. Kinematic trajectories associated with such gestures should therefore be consistent with a second-order dynamical system, possibly modified by blending with temporally overlapping gestures or altering oscillator parameters. This account of observed kinematics is powerful and theoretically appealing, but may be insufficient to account for deviations from predicted kinematics—i.e., changes produced in response to some external perturbations to the jaw, changes in control during acquisition and development, or effects of word/syllable frequency. Optimization, such as would be needed to minimize articulatory effort, is also incompatible with the current TD model, though the idea that the speech production systems economizes effort has a long history and, importantly, also plays a critical role in current theories of domain-general human motor control. To address these issues, we use Dynamic Movement Primitives (DMPs) to expand a dynamical systems framework for speech motor control to allow modification of kinematic trajectories by incorporating a simple, learnable forcing term into existing point attractor dynamics. We show that integration of DMPs with task-based point-attractor dynamics enhances the potential explanatory power of TD in a number of critical ways, including the ability to account for external forces in planning and optimizing both kinematic and dynamic movement costs. At the same time, this approach preserves the successes of Task Dynamics in handling multi-gesture planning and coordination. (shrink)

Developmental coordination disorder is a heterogeneous condition. Besides motor impairments, children with DCD often exhibit poor visual perceptual skills and executive functions. This study aimed to characterize the motor, perceptual, and cognitive profiles of children with DCD at the group level and in terms of subtypes. A total of 50 children with DCD and 31 typically developing peers underwent a comprehensive neuropsychological and motor assessment. The percentage of children with DCD showing impairments in each measurement was first (...) described. Hierarchical agglomerative and K-means iterative partitioning clustering analyses were then performed to distinguish the subtypes present among the complete sample of children in a data-driven way. Moderate to large percentages of children with DCD showed impaired executive functions and praxis, as well as attentional, visual perceptual, and visuomotor skills. Clustering analyses identified five subtypes, four of them mainly consisting of children with DCD and one of TD children. These subtypes were characterized by: generalized impairments, impaired manual dexterity, poor balance, planning, and alertness, impaired manual dexterity, cognitive inhibition, and poor visual perception, impaired manual dexterity and cognitive inhibition, and no impairment. Besides subtle differences, the motor and praxis measures did not enable to discriminate between the four subtypes of children with DCD. The subtypes were, however, characterized by distinct perceptual or cognitive impairments. These results highlight the importance of assessing exhaustively the perceptual and cognitive skills of children with DCD. (shrink)

Glover's planning–control model is based on his finding that visual illusions exert a larger effect in early phases than in late phases of a movement. But evidence for this dynamic illusion effect is weak, because: (a) it appears difficult to replicate; (b) Glover overestimates the accuracy of his results; and (c) he seems to underestimate the illusion effect at late phases.

Human motor skills are exceptional compared to other species, no less than their cognitive skills. In this perspective paper, we suggest that “movement matters!,” implying that motor development is a crucial driving force of cognitive development, much more impactful than previously acknowledged. Thus, we argue that to fully understand and explain developmental changes, it is necessary to consider the interaction of motor and cognitive skills. We exemplify this argument by introducing the concept of “embodied planning,” which (...) takes an embodied cognition perspective on planning development throughout childhood. From this integrated, comprehensive framework, we present a novel climbing paradigm as the ideal testbed to explore the development of embodied planning in childhood and across the lifespan. Finally, we outline future research directions and discuss practical applications of the work on developmental embodied planning for robotics, sports, and education. (shrink)

The overall goal of this target article is to demonstrate a mechanism for an embodied cognition. The particular vehicle is a much-studied, but still widely debated phenomenon seen in 7–12 month-old-infants. In Piaget's classic “A-not-B error,” infants who have successfully uncovered a toy at location “A” continue to reach to that location even after they watch the toy hidden in a nearby location “B.” Here, we question the traditional explanations of the error as an indicator of infants' concepts of objects (...) or other static mental structures. Instead, we demonstrate that the A-not-B error and its previously puzzling contextual variations can be understood by the coupled dynamics of the ordinary processes of goal-directed actions: looking, planning, reaching, and remembering. We offer a formal dynamic theory and model based on cognitive embodiment that both simulates the known A-not-B effects and offers novel predictions that match new experimental results. The demonstration supports an embodied view by casting the mental events involved in perception, planning, deciding, and remembering in the same analogic dynamic language as that used to describe bodily movement, so that they may be continuously meshed. We maintain that this mesh is a pre-eminently cognitive act of “knowing” not only in infancy but also in everyday activities throughout the life span. Key Words: cognitive development; dynamical systems theory; embodied cognition; infant development; motor control; motor planning; perception and action. (shrink)

Choice reaction tasks are performed faster when stimulus location corresponds to response location. This spatial stimulus–response compatibility effect affects performance at the level of action planning and execution. However, when response selection is completed before movement initiation, the Simon effect arises only at the planning level. The aim of this study was to ascertain whether when a precocious response selection is requested, the Simon effect can be detected on the kinematics characterizing the online control phase of a non-ballistic (...) movement. Participants were presented with red or green colored squares, which could appear on the right, left, above, or below a central cross. Depending on the square's color, participants had to release one of two buttons, then reach toward and press a corresponding lateral pad. We found evidence of the Simon effect on both action planning and on-line control. Moreover, the investigation of response conflict at the level of previous trials, a factor that might determine interference at the level of the current response, revealed a conflict adaptation process across trials. Results are discussed in terms of current theories concerned with the Simon effect and the distinction between action planning and control. (shrink)

It is well known that common objects in the environment can evoke possibilities of action, but what about their bi-dimensional representation? Do pictures or paintings that represent action-related objects evoke the same possibilities of actions of the objects that they represent? In contemporary cognitive science, there are two contrasting views on this issue. On the one hand, the ecological-dispositional approach to perception supports the idea that viewing depicted objects as endowed with the potential for action is nothing but an illusion. (...) On the other hand, recent findings show that our motor system is activated by the perception of both real and depicted action-related objects, and this activation plays a functional role in planning motor acts. A broad analysis reveals that the activation of the motor system during perceptual tasks plays a crucial rule in processing the practical meaning of the concrete objects and of the abstract representations of them. This evidence has consequences to our understanding of the way we experience pictures and paintings. (shrink)

The article considers the problem of navigating mobile robots and finding the best way to the goal in real-time in a space surrounded by unknown objects. The motor actions of the robot must be defined and adapted to changes in the environment. When using only laser scanners on mobile work, objects above or below the lasers' level will remain obstacles to the robot. Current algorithms and principles of navigation are considered. Extended the existing real-time interference detection system using lasers (...) by adding a camera that calculates the length of objects. The new system has been successfully implemented and tested in a mobile robot, ensuring the passage of the road providing collision-free paths. The obtained simulation results are presented in the article. The existing problems of navigation of mobile robots, which are moving in the particular area from their position to the specified destination on the map, were investigated. The current problem is the inability to spot objects that are not on the same level as the mobile robot's lasers. Moreover, the task is complicated when you need to recognize such objects while the robot is moving in real time. The current algorithms and principles of navigation given by previous research and publications are analyzed. As a result of the work, the existing system of recognition and avoidance of obstacles was expanded. Prior to that, the system used only odometry and information obtained from laser scanners, without obtaining data from other sources of environmental information. The idea of development was to use a camera, which was already part of the components of the researched mobile robot. It has become possible to generate a pointcloud relative to the environment, using a depth sensing camera to calculate the distance to objects. Because the density of the received data in the form of a pointcloud is too high for further processing, a downsample VoxelGrid filter was used, which reduces the density of the point cloud. VoxelGrid belongs to the PCL library. Another problem was the removal of information about unnecessary objects in the camera's field of view. These include the floor, ceiling, parts of the robot. The PassThrough filter from the PCL library was used to solve this problem. The next step is to process the filtered data using OctoMap. As a result, an octree is generated. A top-down projection is created from the octree generated in the previous step. The resulting projection must be processed and converted into polygonal obstacles. Only then they will be marked by teb_local_planner as obstacles. The developed system was successfully implemented and tested both in the Gazebo simulation and in the researche mobile robot. The path with obstacles will be completed without collisions. The paper presents the obtained test results. (shrink)

This study evaluated the effects of an exergame program combined with traditional tennis training on autonomic regulation, tennis technique, gross motor skills, clinical reaction time, and cognitive inhibitory control in children. Sixty-three children were randomized into four groups and compared at baseline, 6-month immediately post intervention and at 1-year follow-up post intervention. At 6-month post intervention the combined exergame and regular training sessions revealed: higher breathing frequency, heart rate and lower skin conductance levels during exergaming; additional benefits in the (...) point of contact and kinetic chain elements of the tennis forehand and backhand technique ; negative impact on the shot preparation and the follow-through elements ; higher ball skills ; higher percentages of clinical reaction time improvement and cognitive inhibitory control improvement in both congruent and incongruent trials. The 1-year follow-up test showed no differences in the tennis technique, clinical reaction time and cognitive inhibitory control improvement between groups with the same number of trainings per week. The findings support exergaming as an additional training tool, aimed to improve important cognitive-motor tennis skills by adding dynamics to the standardized training process. Caution should be placed to planning this training, e.g., in a mesocycle, since exergaming might decrease the improvement of specific tennis technique parts of the trainees.. (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.

COVID-19 Lockdown was particularly challenging for most mothers of people with intellectual disabilities, including those with Rett syndrome, leading to feelings of abandonment from healthcare services of their children. Within those days, telerehabilitation has represented a valid alternative to support physical activity and treatment, supporting parents in structuring their children’s daily routine at home. This article aims to describe the well-being level of two groups of mothers of girls and women with RTT who were involved in a home-based remotely supervised (...) motor rehabilitation program, respectively, before and during the COVID-19 Italian lockdown. Forty participants with classic RTT were recruited before the lockdown and randomly assigned to two groups that performed the intervention immediately before and during the lockdown, respectively. The intervention included an individualized daily physical activity program carried out for 12 weeks by participants’ parents and fortnightly supervised throughout Skype contacts to plan, monitor, and accommodate individual activities in the participant’s life at home. The short form Caregivers Well-Being Scale was collected for the mothers in each group 12 weeks before intervention, at intervention initiation, immediately after intervention termination, as well as at 12 weeks after intervention termination. Mothers of participants in the Group 1 showed a stable level of well-being across all four evaluations with a slight improvement during the lockdown, without significant change. Similarly, the well-being level of mothers in the Group 2 showed a statistically significant increase in their well-being between T2 and T3 and its reduction to the pre-intervention level between T3 and T4. The results suggest that the lockdown did not negatively affect the participants’ mothers’ well-being, leading to its improvement. Moreover, the proposed intervention could have supported the mothers in managing the new daily routine at home, positively affecting maternal well-being. (shrink)

According to Alvin Plantinga, the cornerstone of epistemology is the proper functioning of our cognitive faculties in accordance with the design plan. In this paper I will explore two aspects of the design plan that are of central relevance to the acquisition of warranted true beliefs. In the first place, perceptual beliefs were supposed to be taken in the basic way and should therefore constitute highly warranted true beliefs. Scale errors in young children pose serious problems for this argument, while (...) they show that part of the visual system may be misguided by perceptual beliefs, as a normal part of the development of the human design plan. Secondly, the ascription of mental states to other persons does not depend on deductive or inductive inference from behaviour. However, the discovery of so-called ‘mirror-neurons' suggests that motor simulation of observed behaviour plays a crucial role in understanding the intentions of others. I conclude by arguing for a refinement of the notion of ‘design plan', guided by recent approaches in cognitive science that should make Plantinga's externalist account at least falsifiable. South African Journal of Philosophy Vol. 26 (3) 2007: pp. 319-328. (shrink)

When participants are asked to make sensibility judgments on sentences that describe action toward the body (i.e., “Mark dealt the cards to you”) or away from the body (i.e., “You dealt the cards to Mark”), they are faster to respond when the response requires an arm movement in the same direction as the action described by the sentence. This congruence effect is known as the Action–Sentence Compatibility Effect (ACE). This study reports 4 experiments that extend our understanding of the ACE (...) by exploring how the time at which one prepares the motor response required for the sensibility judgment affects the magnitude of the ACE. Results show that the ACE arises only when participants have the opportunity to plan their motor response while they are processing the sentence. (shrink)