The functional significance of arm movements in neonates

Handedness as a major determinant of lateral bias in human functional cradling

Studies examining infant cradling have almost uniformly concluded with a general human left-side bias for cradling, indicating that people prefer to hold an infant to the left of their body. Explanations for the notion of the left-side cradling bias have traditionally been searched for in a variety of factors, for example, in terms of maternal heartbeat, genetic factors, in the form of an ear asymmetry where auditory information is perceived faster through the left ear, as a result of a right hemispheric functional specialization for perception of emotions and faces, and in identifying a motor bias of the infant, such as the tendency of newborn infants to lie with the face to the right when placed supine. Interestingly, handedness is generally considered an inadequate explanation for the lateralized cradling bias, despite it being an intuitively plausible one. In this brief review, I put forward the cradler's handedness as the most convincing and elegant determinant of the cradling bias. This explanation is consistent with a developmental cascades' framework where the cradling bias can be understood as the result of a multitude of factors across a range of levels and systems.

Biological and environmental factors may affect children's executive function through motor and sensorimotor development: Preterm birth and cerebral palsy

Disruptive biological and environmental factors may undermine the development of children's motor and sensorimotor skills. Since the development of cognitive skills, including executive function, is grounded in early motor and sensorimotor experiences, early delays or impairments in motor and sensorimotor processing often trigger dynamic developmental cascades that lead to suboptimal executive function outcomes. The purpose of this perspective paper is to link early differences in motor/sensorimotor processing to the development of executive function in children born preterm or with cerebral palsy. Uncovering such links in clinical populations would improve our understanding of developmental pathways and key motor and sensorimotor skills that are antecedent and foundational for the development of executive function. This knowledge will allow the refinement of early interventions targeting motor and sensorimotor skills with the goal of proactively improving executive function outcomes in at-risk populations.

How babies use their hands to learn about objects: Exploration, reach-to-grasp, manipulation, and tool use

Object play is essential for infant learning, and infants spend most of their day with objects. Young infants learn about objects and their properties through multimodal exploration facilitated by caregivers. They figure out how to transport their hands to where objects are, and how to grasp objects in increasingly complex ways. Building on earlier experiences, they learn how to use their hands collaboratively to act on objects, and how to use objects to act on other objects in instrumental ways. These changes in how infants use their hands occur during the most rapid period of motor development and may have important downstream implications for other domains. Recent research findings have established the importance of effective fine motor skills for later academic skills, yet our understanding of the factors that influence the early development of hand skills is sparse at best. Latest research on reaching, grasping, object manipulation, hands collaboration, and tool use is reviewed and connections among these developments are explained from the perspective of developmental cascades. This article is categorized under: Psychology > Motor Skill and Performance Psychology > Development and Aging.

Early, concurrent, and consistent hand preferences predict stacking in toddlerhood

Stacking is a hallmark of fine motor skill development and requires skilled hand use. One mechanism for children to gain manual proficiency involves establishing a hand preference that creates practice differences between the hands as the preferred hand is used more often and in different ways than the other. Prior work found that stacking skill emerged earlier for infants with an identifiable hand preference. However, it is not known how hand preference relates to later toddler stacking performance. This study examined the effects of early hand preference (infant pattern), concurrent hand preference (toddler pattern), and consistent hand preference (infant to toddler pattern) on toddler stacking skills. Sixty-one toddlers, whose hand preferences as infants were known, were assessed for their toddler hand preference and their stacking skill across 7 monthly visits from 18 to 24 months of age. Using multilevel Poisson longitudinal analysis, children with hand preferences that were consistent across both infancy and toddlerhood were more successful at stacking, compared to those with inconsistent preferences across the infant and toddler periods. Thus, consistency of hand preferences during the first 2 years likely contributes toward individual differences in the development of fine motor skills.

Dynamical systems model of development of the action differentiation in early infancy: a requisite of physical agency

Young infants are sensitive to whether their body movements cause subsequent events or not during the interaction with the environment. This ability has been revealed by empirical studies on the reinforcement of limb movements when a string is attached between an infant limb and a mobile toy suspended overhead. A previous study reproduced the experimental observation by modeling both the infant's limb and a mobile toy as a system of coupled oscillators. The authors then argued that emergence of agency could be explained by a phase transition in the dynamical system: from a weakly coupled state to a state where the both movements of the limb and the toy are highly coordinated. However, what remains unexplained is the following experimental observation: When the limb is connected to the mobile toy by a string, the infant increases the average velocity of the arm's movement. On the other hand, when the toy is controlled externally, the average arm's velocity is greatly reduced. Since young infants produce exuberant spontaneous movements even with no external stimuli, the inhibition of motor action to suppress the formation of spurious action-perception coupling should be also a crucial sign for the emergence of agency. Thus, we present a dynamical system model for the development of action differentiation, to move or not to move, in the mobile task. In addition to the pair of limb and mobile oscillators for providing positive feedback for reinforcement in the previous model, bifurcation dynamics are incorporated to enhance or inhibit self-movements in response to detecting contingencies between the limb and mobile movements. The results from computer simulations reproduce experimental observations on the developmental emergence of action differentiation between 2 and 3 months of age in the form of a bifurcation diagram. We infer that the emergence of physical agency entails young infants' ability not only to enhance a specific action-perception coupling, but also to decouple it and create a new mode of action-perception coupling based on the internal state dynamics with contingency detection between self-generated actions and environmental events.

Newborns modulate their crawling in response to their native language but not another language

Human newborns can propel themselves to their mother's breast when positioned skin to skin on her abdomen just after birth. For decades, researchers have considered this primitive crawling behavior a spinal reflex, immune to supra spinal control. However, recent research suggests that neonatal crawling is already responsive to visual and olfactory stimuli processed at a supra spinal level. Here we report that a few hours post birth, French newborns can also modulate their crawling in response to their native language - a source of information that is processed supra-spinally. The crawling patterns of 23 French-born newborns were recorded on video and via an infrared motion capture system during two randomly ordered 2-min trials. The newborns were secured on a mini skateboard to facilitate arm and leg movements during their crawling propulsion. They heard a repetitive sequence of the same sentences either in French, their native language, or in English, a rhythmically different and hence discriminable unfamiliar language, on each trial. In French, compared to English, crawling was enhanced, with significantly more arm and leg steps and significantly more and larger trunk rotations in the cephalo-caudal axis. Moreover, newborns rotated their heads and trunk toward the appropriate loud speaker when hearing French but not English. These preliminary findings suggest that newborn crawling is not a simple stereotyped reflex under spinal control, but a complex pattern that can be modulated in response to higher-order, supra-spinally processed stimuli. The findings open fascinating questions about the range of stimuli to which newborn crawling is responsive.

Learning limb-specific contingencies in early infancy

Most research with the mobile paradigm has the underlying assumption that young infants can selectively move the limb causing the contingent feedback from the mobile while avoiding irrelevant motor responses. Contrary to this long-held belief, others have argued that such differentiation ability is not fully developed early in life. In the current study, we revisited the traditional mobile paradigm with a contemporary research approach (using high-precision motion capture techniques, a yoked-control design, and a large sample size) to investigate whether response differentiation ability emerges before 5 months of age. The data collected from 76 infants (aged between 115 and 159 days) revealed that infants can learn sensorimotor contingencies by increasing the movement of the connected leg relative to their baseline level. However, they did not differentially increase the movement of the leg causing an effect in the environment compared with that of other limbs. Our results illustrate that response differentiation ability emerges later than previously suggested.

Neonatal manual specialization in language and music conditions: Consistency with the hemispheric specialization adult model

The main purpose of this study was to test in neonates the influence of the sound environment, i.e., language versus music, on asymmetric hand movement activity in the presence of a target object. Based on hemispheric specialization, our hypothesis was that infants would use their right hand more in the speech context (left hemisphere) and their left hand more in the music context (right hemisphere). The study involved 19 full-term 3-day-old neonates. An object was presented successively in the two sound environments in counterbalance order for 120 s each. Left and right movements and mouth activity were scored during the target object presentation. Results show that neonates moved their left hand twice as much as their right hand in the music condition than in the language condition, and they moved their right hand a longer time in the language condition than in the music condition. The average number of sucking bursts was significantly higher in the language condition than in the music condition. We discuss the results in terms of manual specialization in relation to the development of hemispheric specialization.

From Hemispheric Asymmetry through Sensorimotor Experiences to Cognitive Outcomes in Children with Cerebral Palsy

Recent neuroimaging studies allowed us to explore abnormal brain structures and interhemispheric connectivity in children with cerebral palsy (CP). Behavioral researchers have long reported that children with CP exhibit suboptimal performance in different cognitive domains (e.g., receptive and expressive language skills, reading, mental imagery, spatial processing, subitizing, math, and executive functions). However, there has been very limited cross-domain research involving these two areas of scientific inquiry. To stimulate such research, this perspective paper proposes some possible neurological mechanisms involved in the cognitive delays and impairments in children with CP. Additionally, the paper examines the ways motor and sensorimotor experience during the development of these neural substrates could enable more optimal development for children with CP. Understanding these developmental mechanisms could guide more effective interventions to promote the development of both sensorimotor and cognitive skills in children with CP.

Infants exploring objects: A cascades perspective

Infants spend much of their time exploring objects (Herzberg et al., 2021), and object exploration is linked to learning and development in various domains (e.g., social, cognitive, motor). But how does exploration develop in the first place, and how, exactly, does exploration promote learning? One way to approach these process-oriented questions is with a developmental cascades perspective, which holds that new skills emerge from earlier-developing ones and that various interactions with people and objects accumulate over time to influence multiple domains of development (Masten & Cicchetti, 2010). In this chapter, we describe object exploration from a developmental cascades perspective. In Section 2, we describe typical and atypical trajectories of exploration behaviors, noting how these behaviors emerge from earlier-developing cognitive and motor skills. In Section 3, we discuss how object exploration opens the door for new types of learning opportunities. In Section 4, we discuss early experiences that may shape the development of object exploration. Altogether, we aim to convey that new developments in exploration skills are extensions of earlier-developing skills, and that seemingly insignificant exploratory behaviors (e.g., shaking a rattle) may result in numerous and varied consequences for the developing infant.

Great apes' understanding of biomechanics: eye-tracking experiments using three-dimensional computer-generated animations

Visual processing of the body movements of other animals is important for adaptive animal behaviors. It is widely known that animals can distinguish articulated animal movements even when they are just represented by points of light such that only information about biological motion is retained. However, the extent to which nonhuman great apes comprehend the underlying structural and physiological constraints affecting each moving body part, i.e., biomechanics, is still unclear. To address this, we examined the understanding of biomechanics in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), following a previous study on humans (Homo sapiens). Apes underwent eye tracking while viewing three-dimensional computer-generated (CG) animations of biomechanically possible or impossible elbow movements performed by a human, robot, or nonhuman ape. Overall, apes did not differentiate their gaze between possible and impossible movements of elbows. However, some apes looked at elbows for longer when viewing impossible vs. possible robot movements, which indicates that they may have had knowledge of biomechanics and that this knowledge could be extended to a novel agent. These mixed results make it difficult to draw a firm conclusion regarding the extent to which apes understand biomechanics. We discuss some methodological features that may be responsible for the results, as well as implications for future nonhuman animal studies involving the presentation of CG animations or measurement of gaze behaviors.

Making the World Behave: A New Embodied Account on Mobile Paradigm

In this review article, we describe the mobile paradigm, a method used for more than 50 years to assess how infants learn and remember sensorimotor contingencies. The literature on the mobile paradigm demonstrates that infants below 6 months of age can remember the learning environment weeks after when reminded periodically and integrate temporally distributed information across modalities. The latter ability is only possible if events occur within a temporal window of a few days, and the width of this required window changes as a function of age. A major critique of these conclusions is that the majority of this literature has neglected the embodied experience, such that motor behavior was considered an equivalent developmental substitute for verbal behavior. Over recent years, simulation and empirical work have highlighted the sensorimotor aspect and opened up a discussion for possible learning mechanisms and variability in motor preferences of young infants. In line with this recent direction, we present a new embodied account on the mobile paradigm which argues that learning sensorimotor contingencies is a core feature of development forming the basis for active exploration of the world and body. In addition to better explaining recent findings, this new framework aims to replace the dis-embodied approach to the mobile paradigm with a new understanding that focuses on variance and representations grounded in sensorimotor experience. Finally, we discuss a potential role for the dorsal stream which might be responsible for guiding action according to visual information, while infants learn sensorimotor contingencies in the mobile paradigm.

Newborn crawling and rooting in response to maternal breast odor

A growing literature shows that perception and action are already tightly coupled in the newborn. The current study aimed to examine the nature of the coupling between olfactory stimuli from the mother and the newborn's crawling and rooting (exploratory movements of the head). To examine the coupling, the crawling and rooting behavior of 28 2-day-old newborns were studied while they were supported prone on a mobility device shaped like a mini skateboard, the Crawliskate®, their head positioned directly on top of a pad infused with either their mother's breast odor (Maternal) or the odor of water (Control). Video and 3D kinematic analyses of the number and types of limb movements and quantification of displacement across the surface revealed that newborns are significantly more efficient crawlers when they smell the maternal odor, moving greater distances although performing fewer locomotor movements. In addition, the newborns made significantly more head rooting movements in the presence of the maternal odor. These findings suggest that the circuitry underlying quadrupedal locomotion and exploratory movements of the head is already adaptable to olfactory information via higher brain processing. Moreover, the coupling between olfaction and the two action systems, locomotion and rooting, is already differentiated. As crawling enables the newborn to move toward the mother's breast immediately after birth and facilitates mother-infant interaction, the results of this study highlight the potential value of using maternal odors to stimulate mobility in infants at risk of motor delay and/or deprived of this odor when born prematurely.

The Development of Bimanual Coordination Across Toddlerhood

As one of the hallmarks of human activity and cultural achievement, bimanual coordination has been the focus of research efforts in multiple fields of inquiry. Since the seminal work of Cohen (1971) and Kelso and colleagues (Haken, Kelso, & Bunz, 1985; Kelso, Southard, & Goodman, 1979), bimanual action has served as a model system used to investigate the role of cortical, perceptual, cognitive, and situational underpinnings of coordinated movement sequences (e.g., Bingham, 2004; Oliveira & Ivry, 2008). This work has been guided primarily by dynamical systems theory in general, and by the formal Haken-Kelso-Bunz (HKB; 1985) model of bimanual coordination, in particular. The HKB model describes the self-organizing relationship between a coordinated movement pattern and the underlying parameters that support that pattern, and can also be used to conceptualize and test predictions of how changes in coordination occur. Much of the work investigating bimanual control under the HKB model has been conducted with adults who are acting over time periods of a few seconds to a few days. However, there are also changes in bimanual control that occur over far longer time spans, including those that emerge across childhood and into adolescence (e.g., Wolff, Kotwica, & Obregon, 1998). Using the formal HKB model as a starting point, we analyzed the ontogenetic emergence of a particular pattern of bimanual coordination, specifically, the anti-phase (or inverse oscillatory motion) coordination pattern between the upper limbs in toddlers who are performing a drumming task (see Brakke, Fragaszy, Simpson, Hoy, & Cummins-Sebree, 2007). This study represents a first attempt to document the emergence of the anti-phase pattern by examining both microgenetic and ontogenetic patterns of change in bimanual activity. We report the results of a longitudinal study in which seven toddlers engaged monthly in a bimanual drumming task from 15 to 27 months of age. On some trials, an adult modeled in-phase or anti-phase action; on other trials, no action was modeled. We documented the motion dynamics accompanying the emergence of the anti-phase bimanual coordination pattern by assessing bout-to-bout and month-to-month changes in several movement parameters-oscillation frequency, amplitude ratio of the drumsticks, initial position of the limbs to begin bouts, and primary arm-joint involvement. These parameters provided a good starting point to understand how toddlers explore movement space in order to achieve greater stability in performing the anti-phase coordination pattern. Trained research assistants used Motus software to isolate each bout of drumming and to digitize the movement of the two drumstick heads relative to the stationary drum surface. Because we were primarily interested in the vertical movement of the drumsticks that were held in the child's hands, we relied on two-dimensional analyses and analyzed data that were tracked by a single camera. We used linear mixed effects analyses as well as qualitative analyses for each participant to help elucidate the emergence and stability of the child's use of anti-phase coordination. This approach facilitated descriptions of individual pathways of behavior that are possible only with longitudinal designs such as the one used here. Our analyses indicated that toddlers who were learning to produce anti-phase motion in this context employed a variety of strategies to adjust the topography of their action. Specifically, as we hypothesized, toddlers differentially exploited oscillation frequency and movement amplitude to support change to anti-phase action, which briefly appeared as early as 15 months of age but did not become relatively stable until approximately 20 months of age. We found evidence that many toddlers reduced oscillation frequency before transitioning from in-phase to anti-phase drumming. Toddlers also used different means of momentarily modulating the amplitude ratio between limbs to allow a change in coordination from in-phase to anti-phase. Nevertheless, these oscillation-frequency and amplitude-ratio strategies were interspersed by periods of nonsystematic exploration both within and between bouts of practice. We also observed that toddlers sometimes changed their initial limb positions to start a bout or altered which primary arm joints they used when drumming. When they enacted these changes, the toddlers increased performance of the anti-phase coordination pattern in their drumming. However, we found no evidence of systematic exploration with these changes in limb position and joint employment, suggesting that the toddlers did not intentionally employ these strategies to improve their performance on the task. Although bimanual drumming represents a highly specific behavior, our examination of the mechanisms underlying emergence of the anti-phase coordination pattern in this context is one of the missing pieces needed to understand the development of motor coordination more broadly. Our results document that the anti-phase coordination pattern emerges and stabilizes through modulation of the dynamics of the movement and change of the attractor landscape (i.e., the motor repertoire). Consistent with literatures in motor control, motor learning, and skill development, our results suggest that the acquisition of movements in ontogenetic development can be thought of as exploration of the emergent dynamics of perception and action. This conclusion is commensurate with a systemic approach to motor development in which functional dynamics, rather than specific structures, provide the basis for understanding developmental changes in skill. Based on our results as well as the relevant previous empirical literature, we present a conceptual model that incorporates developmental dynamics into the HKB model. This conceptual model calls for new investigations using a dynamical systems approach that allows direct control of movement parameters, and that builds on the methods and phenomena that we have described in the current work.

The Developing Bodily Self: How Posture Constrains Body Representation in Childhood

Adults' body representation is constrained by multisensory information and knowledge of the body such as its possible postures. This study (N = 180) tested for similar constraints in children. Using the rubber hand illusion with adults and 6- to 7-year olds, we measured proprioceptive drift (an index of hand localization) and ratings of felt hand ownership. The fake hand was either congruent or incongruent with the participant's own. Across ages, congruency of posture and visual-tactile congruency yielded greater drift toward the fake hand. Ownership ratings were higher with congruent visual-tactile information, but unaffected by posture. Posture constrains body representation similarly in children and adults, suggesting that children have sensitive, robust mechanisms for maintaining a sense of bodily self.

The teleological stance: Past, present, and future

We review the support for, and criticisms of, the teleological stance theory, often described as a foundation for goal-directed action understanding early in life. A major point of contention in the literature has been how teleological processes and assumptions of rationality are represented and understood in infancy, and this debate has been largely centered on three paradigms. Visual habituation studies assess infant's abilities to retrospectively assess teleological processes; the presence of such processes is supported by the literature. Rational imitation is a phenomenon that has been questioned both theoretically and empirically, and there is currently little support for this concept in the literature. The involvement of teleological processes in action prediction is unclear. To date, the ontology of teleological processes remains unspecified. To remedy this, we present a new action-based theory of teleological processes (here referred to as the embodied account of teleological processes), based on the development of goal-directed reaching with its origin during the fetal period and continuous development over the first few months of life.

Sensorimotor Contingencies as a Key Drive of Development: From Babies to Robots

Much current work in robotics focuses on the development of robots capable of autonomous unsupervised learning. An essential prerequisite for such learning to be possible is that the agent should be sensitive to the link between its actions and the consequences of its actions, called sensorimotor contingencies. This sensitivity, and more particularly its role as a key drive of development, has been widely studied by developmental psychologists. However, the results of these studies may not necessarily be accessible or intelligible to roboticians. In this paper, we review the main experimental data demonstrating the role of sensitivity to sensorimotor contingencies in infants' acquisition of four fundamental motor and cognitive abilities: body knowledge, memory, generalization, and goal-directedness. We relate this data from developmental psychology to work in robotics, highlighting the links between these two domains of research. In the last part of the article we present a blueprint architecture demonstrating how exploitation of sensitivity to sensorimotor contingencies, combined with the notion of "goal," allows an agent to develop new sensorimotor skills. This architecture can be used to guide the design of specific computational models, and also to possibly envisage new empirical experiments.

Development of body knowledge as measured by arm differentiation in infants: From global to local?

The ability to sense and use the body parts in an organized and differentiated manner is a precursor of body knowledge in infancy. To acquire this ability, the infant's brain might explore the perceptual consequences of its bodily actions. Undifferentiated body movements would gradually be replaced by more precise actions. Only a very few studies have tested this ‘global‐to‐local’ hypothesis, and none of them have so far been replicated. In this study, we assessed arm differentiation in 4‐, 6‐, and 8‐month‐old infants using a new contingency detection task in which infants have to detect a contingency between one of their arms’ activity and an audiovisual stimulus on a screen. We found that 4‐ to 8‐month‐old infants seem to be able to use their arms in a differentiated manner. However, surprisingly, we were not able to show a developmental trend in arm differentiation between 4 and 8 months of age.

The role of sensorimotor experience in the development of mimicry in infancy

During social interactions we often have an automatic and unconscious tendency to copy or 'mimic' others' actions. The dominant view on the neural basis of mimicry appeals to an automatic coupling between perception and action. It has been suggested that this coupling is formed through associative learning during correlated sensorimotor experience. Although studies with adult participants have provided support for this hypothesis, little is known about the role of sensorimotor experience in supporting the development of perceptual-motor couplings, and consequently mimicry behaviour, in infancy. Here we investigated whether the extent to which an observed action elicits mimicry depends on the opportunity an infant has had to develop perceptual-motor couplings for this action through correlated sensorimotor experience. We found that mothers' tendency to imitate their 4-month-olds' facial expressions during a parent-child interaction session was related to infants' facial mimicry as measured by electromyography. Maternal facial imitation was not related to infants' mimicry of hand actions, and instead we found preliminary evidence that infants' tendency to look at their own hands may be related to their tendency to mimic hand actions. These results are consistent with the idea that mimicry is supported by perceptual-motor couplings that are formed through correlated sensorimotor experience obtained by observing one's own actions and imitative social partners.

Self-Unity as Ground Zero of Learning and Development

Contrary to the suggestion that we are born in a state of confusion and primordial state of a-dualism with the environment, infancy research of the past 40 years shows that from the outset, infants are objective perceivers guided by rich evolved survival values of approach and avoidance in relation to specific resources in the environment such as faces, food, or smell. This starting-state competence drives and organizes their behavior. Evidence-based ascription of self-unity at birth is discussed. Selected findings are presented suggesting that self-unity is a primordial human experience, the main organizer of behavior from the outset. Self-unity is the necessary ground zero enabling the rapid learning and development taking place early in human life.

Learning and Acting in Peripersonal Space: Moving, Reaching, and Grasping

The young infant explores its body, its sensorimotor system, and the immediately accessible parts of its environment, over the course of a few months creating a model of peripersonal space useful for reaching and grasping objects around it. Drawing on constraints from the empirical literature on infant behavior, we present a preliminary computational model of this learning process, implemented and evaluated on a physical robot. The learning agent explores the relationship between the configuration space of the arm, sensing joint angles through proprioception, and its visual perceptions of the hand and grippers. The resulting knowledge is represented as the peripersonal space (PPS) graph, where nodes represent states of the arm, edges represent safe movements, and paths represent safe trajectories from one pose to another. In our model, the learning process is driven by a form of intrinsic motivation. When repeatedly performing an action, the agent learns the typical result, but also detects unusual outcomes, and is motivated to learn how to make those unusual results reliable. Arm motions typically leave the static background unchanged, but occasionally bump an object, changing its static position. The reach action is learned as a reliable way to bump and move a specified object in the environment. Similarly, once a reliable reach action is learned, it typically makes a quasi-static change in the environment, bumping an object from one static position to another. The unusual outcome is that the object is accidentally grasped (thanks to the innate Palmar reflex), and thereafter moves dynamically with the hand. Learning to make grasping reliable is more complex than for reaching, but we demonstrate significant progress. Our current results are steps toward autonomous sensorimotor learning of motion, reaching, and grasping in peripersonal space, based on unguided exploration and intrinsic motivation.

Prospective organization of neonatal arm movements: A motor foundation of embodied agency, disrupted in premature birth

Prospective motor control moves the body into the future, from where one is to where one wants to be. It is a hallmark of intentionality. But its origin in development is uncertain. In this study, we tested whether or not the arm movements of newborn infants were prospectively controlled. We measured the spatiotemporal organization of 480 full-term neonatal arm movements and 384 arm movements of prematurely born infants at-risk for neurodevelopmental disorder. We found 75% of healthy term-birth neonatal movements and 68% of prematurely born infant movements conformed to the τG -coupling model of prospective sensorimotor control. Prospective coupling values were significantly reduced in the latter (p = .010, r = .087). In both cases prospectively controlled movements were tightly organized by fixed-duration units with a base duration of 218 ms and additional temporal units of 145 ms. Yet distances remained constant. Thus, we demonstrate for the first time a precise prospective spatiotemporal organization of neonatal arm movements and demonstrate that at-risk infants exhibit reduced sensorimotor control. Prospective motor control is a hallmark of primary sensorimotor intentionality and gives a strong embodied foundation to conscious motor agency.

Hand Recognition Obtained by Simulation of Hand Regard

Eye-hand coordination of an infant is observed during the early months of their development. Hand regard, which is an example of this coordination, occurs at about 2 months. It is considered that after experiencing hand regard, an infant may recognize their own hands. However, it is unknown how an infant recognizes their hands through hand regard. Accordingly, the process by which an infant recognizes their hands and distinguishes between their hands and other objects was simulated. A simple neural network was trained with a modified real-time recurrent learning (RTRL) algorithm to deal with time-varying input and output during hand regard. The simulation results show that information about recognition of the modeled hands of an infant is stored in cell assemblies, which were self-organized. Cell assemblies appear during the phase of U-shaped developments of hand regard, and the configuration of the cell assemblies changes with each U-shaped development. Furthermore, movements like general movements (GMs) appear during the phase of U-shaped developments of hand regard.

Physical Growth, Body Scale, and Perceptual-Motor Development

In this chapter we consider from the theoretical framework of the ecological approach to perception and action, the relations between physical growth and body scale in the context of children's perceptual-motor development. Body scale and the timescale of its change through growth are shown to relate to the emergence and dissolution of the fundamental skills in infancy, the perception of what an environment affords functionally for action, together with the emergent pattern of movement coordination. A central issue in typical and atypical motor development is the mapping of the timescale of adaptive change in the acquisition of perceptual-motor skill to the accompanying timescale of change in physical growth.

The Development of Sensorimotor Intelligence in Infants

Infancy is the most dynamic part of human development. During this period, all basic sensorimotor and cognitive abilities are established. In this chapter, we will trace some of the important achievements of this development with a focus on how infants achieve predictive control of actions, i.e., how they come to coordinate their behavior with the ongoing events in the world without lagging behind. With the maturation of the brain, new possibilities that have profound effects on cognition open up. Some of them are core abilities, i.e., they function at birth or very early in development. Important examples are the structured perception of objects and surfaces and the control of arm movements. Closely after birth, infants move their arms to the vicinity of objects in front of them demonstrating that they have some control of their arms and indicating that they perceive objects as such. Another example is the rapid onset of smooth-pursuit eye movements during the second month of life and the emerging ability to predict when and where an occluded moving object will reappear. At 4months of age, out of sight is no longer of mind. The child's sensorimotor system is especially designed to facilitate the extraction of knowledge about the world including other people. In addition, the infant is endowed with motives that ensure that the innate predispositions are transformed into a system of knowledge for guiding actions predictively. By perceiving and acting on the world, infants develop their cognition and through developmental studies; we can learn more about these processes.

Inherited and Acquired Choreas

Chorea is a symptom of a broad array of genetic, structural, and metabolic disorders. While chorea can result from systemic illness and damage to diverse brain structures, injury to the basal ganglia, especially the putamen or globus pallidus, appears to be a uniting features of these diverse neuropathologies. The timing of onset, rate of progression, and the associated neurological or systemic symptoms can often narrow the differential diagnosis to a few disorders. Recognizing the correct etiology for childhood chorea is critical, as numerous disorders in this category are potentially curable, or are remediable, with early treatment.

Which limb is it? Responses to vibrotactile stimulation in early infancy

This study focuses on how the body schema develops during the first months of life, by investigating infants’ motor responses to localized vibrotactile stimulation on their limbs. Vibrotactile stimulation was provided by small buzzers that were attached to the infants’ four limbs one at a time. Four age groups were compared cross‐sectionally (3‐, 4‐, 5‐, and 6‐month‐olds). We show that before they actually reach for the buzzer, which, according to previous studies, occurs around 7–8 months of age, infants demonstrate emerging knowledge about their body's configuration by producing specific movement patterns associated with the stimulated body area. At 3 months, infants responded with an increase in general activity when the buzzer was placed on the body, independently of the vibrator's location. Differentiated topographical awareness of the body seemed to appear around 5 months, with specific responses resulting from stimulation of the hands emerging first, followed by the differentiation of movement patterns associated with the stimulation of the feet. Qualitative analyses revealed specific movement types reliably associated with each stimulated location by 6 months of age, possibly preparing infants’ ability to actually reach for the vibrating target. We discuss this result in relation to newborns’ ability to learn specific movement patterns through intersensory contingency.

Statement of contribution

what is already known on infants’ sensorimotor knowledge about their own bodies

3‐month‐olds readily learn to produce specific limb movements to obtain a desired effect (movement of a mobile).

infants detect temporal and spatial correspondences between events involving their own body and visual events.

what the present study adds

until 4–5 months of age, infants mostly produce general motor responses to localized touch.

this is because in the present study, infants could not rely on immediate contingent feedback.

we propose a cephalocaudal developmental trend of topographic differentiation of body areas.

Autism is associated with reduced ability to interpret grasping actions of others

We investigated the ability of children with ASD to discriminate a small cylinder from a large cube by observing a point-light movie of an actor grasping the object, either from an allocentric or egocentric viewpoint (observing action of others or self). Compared with typically developing controls, high functioning autistic children showed a strong selective impairment in this task, but only with the allocentric viewpoint, where thresholds were twice as high: egocentric thresholds were similar to age- and ability-matched controls. The magnitude of the impairment correlated strongly with the degree of symptomology (R2 = 0.5). The results suggest that children with ASD might be impaired in their ability to predict and infer the consequences of others' movements, which could be related to the social-communicative deficits often reported in autism.

Self-defense: Deflecting Deflationary and Eliminativist Critiques of the Sense of Ownership

I defend a phenomenological account of the sense of ownership as part of a minimal sense of self from those critics who propose either a deflationary or eliminativist critique. Specifically, I block the deflationary critique by showing that in fact the phenomenological account is itself a deflationary account insofar as it takes the sense of ownership to be implicit or intrinsic to experience and bodily action. I address the eliminativist view by considering empirical evidence that supports the concept of pre-reflective self-awareness, which underpins the sense of ownership. Finally, I respond to claims that phenomenology does not offer a positive account of the sense of ownership by showing the role it plays in an enactivist (action-oriented) view of embodied cognition.

Eye-Hand-Mouth Coordination in the Human Newborn

BACKGROUND

There have been several studies concerning rudimentary coordination of the eyes, hands, and mouth in the human newborn. The author attempted to clarify the ontogenetic significance of the coordination during the earliest period of human life through a systematic review. The neural mechanism underlying the coordination was also discussed based on the current knowledge of cognitive neuroscience.

METHODS

Searches were conducted on PubMed and Google Scholar from their inception through March 2017.

RESULTS

Studies have demonstrated that the coordination is a visually guided goal-directed motor behavior with intension and emotion. Current cognitive research has proved that feeding requires a large-scale neural network extending over several cortices.

CONCLUSION

The eye-hand-mouth coordination in the newborn can be regarded as a precursor of subsequent self-feeding, and the coordination is very likely mediated through the underdeveloped but essentially the same network interconnecting cortices as in the adult.

When the Sound Becomes the Goal. 4E Cognition and Teleomusicality in Early Infancy

In this paper we explore early musical behaviors through the lenses of the recently emerged "4E" approach to mind, which sees cognitive processes as Embodied, Embedded, Enacted, and Extended. In doing so, we draw from a range of interdisciplinary research, engaging in critical and constructive discussions with both new findings and existing positions. In particular, we refer to observational research by French pedagogue and psychologist François Delalande, who examined infants' first "sound discoveries" and individuated three different musical "conducts" inspired by the "phases of the game" originally postulated by Piaget. Elaborating on such ideas we introduce the notion of "teleomusicality," which describes the goal-directed behaviors infants adopt to explore and play with sounds. This is distinguished from the developmentally earlier "protomusicality," which is based on music-like utterances, movements, and emotionally relevant interactions (e.g., with primary caregivers) that do not entail a primary focus on sound itself. The development from protomusicality to teleomusicality is discussed in terms of an "attentive shift" that occurs between 6 and 10 months of age. This forms the basis of a conceptual framework for early musical development that emphasizes the emergence of exploratory, goal-directed (i.e., sound-oriented), and self-organized musical actions in infancy. In line with this, we provide a preliminary taxonomy of teleomusical processes discussing "Original Teleomusical Acts" (OTAs) and "Constituted Teleomusical Acts" (CTAs). We argue that while OTAs can be easily witnessed in infants' exploratory behaviors, CTAs involve the mastery of more specific and complex goal-directed chains of actions central to musical activity.

Examining the Spatiotemporal Disruption to Gaze When Using a Myoelectric Prosthetic Hand

The aim of this study was to provide a detailed account of the spatial and temporal disruptions to eye-hand coordination when using a prosthetic hand during a sequential fine motor skill. Twenty-one able-bodied participants performed 15 trials of the picking up coins task derived from the Southampton Hand Assessment Procedure with their anatomic hand and with a prosthesis simulator while wearing eye-tracking equipment. Gaze behavior results revealed that when using the prosthesis, performance detriments were accompanied by significantly greater hand-focused gaze and a significantly longer time to disengage gaze from manipulations to plan upcoming movements. The study findings highlight key metrics that distinguish disruptions to eye-hand coordination that may have implications for the training of prosthesis use.

An Embodied Account of Early Executive-Function Development

The importance of executive functioning for later life outcomes, along with its potential to be positively affected by intervention programs, motivates the need to find early markers of executive functioning. In this study, 18-month-olds performed three executive-function tasks-involving simple inhibition, working memory, and more complex inhibition-and a motion-capture task assessing prospective motor control during reaching. We demonstrated that prospective motor control, as measured by the peak velocity of the first movement unit, is related to infants' performance on simple-inhibition and working memory tasks. The current study provides evidence that motor control and executive functioning are intertwined early in life, which suggests an embodied perspective on executive-functioning development. We argue that executive functions and prospective motor control develop from a common source and a single motive: to control action. This is the first demonstration that low-level movement planning is related to higher-order executive control early in life.

Using senses to encourage head and upper limb voluntary movement in young infants: Implications for early intervention

PRIMARY OBJECTIVE

It has long been suggested that a neonate's movement and responses to external stimuli are the product of reflexive reactions rather than purposeful movements. However, several studies have demonstrated that this is not the case. Rationale of literature included: This study seeks to review reports showing that sensory stimuli resulted in newborns recognising and responding to different stimuli with active head or upper limb movements. We also discuss this in the context of current literature about early training on the advancement of movement and brain development. Results and outcomes: Taken together, it is clear that early active experience shapes learning in newborns.

CONCLUSIONS

The impact of this research is most exciting for applications that would induce infants to make purposeful movements, especially as a means for early intervention and rehabilitation for the treatment of infants with or at high risk for developmental delay.

The Extended Mirror Neuron Network

Mirror neurons (MNs) are a fascinating class of cells originally discovered in the ventral premotor cortex (PMv) and, subsequently, in the inferior parietal lobule (IPL) of the macaque, which become active during both the execution and observation of actions. In this review, I will first highlight the mounting evidence indicating that mirroring others’ actions engages a broad system of reciprocally connected cortical areas, which extends well beyond the classical IPL-PMv circuit and might even include subcortical regions such as the basal ganglia. Then, I will present the most recent findings supporting the idea that the observation of one’s own actions, which might play a role in the ontogenetic origin and tuning of MNs, retains a particular relevance within the adult MN system. Finally, I will propose that both cortical and subcortical mechanisms do exist to decouple MN activity from the motor output, in order to render it exploitable for high-order perceptual, cognitive, and even social functions. The findings reviewed here provide an original framework for envisaging the main challenges and experimental directions of future neurophysiological and neuroanatomical studies of the monkey MN system.

The Corticospinal System: From Development to Motor Control

The corticospinal system is the principal motor system for controlling movements that require the greatest skill and flexibility. It is the last motor system to develop. The pattern of termination of corticospinal axons, as they grow into the spinal gray matter, bears little resemblance to the pattern later in development and in maturity. Refinement of corticospinal terminations occurs during a protracted postnatal period and includes both elimination of transient terminations and growth to new targets. This refinement is driven by neural activity in the motor cortical areas and by limb motor experience. Developing corticospinal terminals compete with each other for synaptic space on spinal neurons. More active terminals are more competitive and are able to secure more synaptic space than their less active counterparts. Corticospinal terminals can activate spinal neurons from very early in development. The importance of this early synaptic activity appears to be more for refining corticospinal connections than for transmitting signals to spinal motor circuits for movement control. The motor control functions of the corticospinal system are not expressed until development of connectional specificity with spinal cord neurons, a strong capacity for corticospinal synapses to facilitate spinal motor circuits, and the formation of the cortical motor map.

Eye-Mouth Associated Movement in the Human Newborn and Very Young Infant

BACKGROUND

The aim of this study is to demonstrate that goal-directed eye-mouth associated movement exists in the newborn and very young infant.

METHODS

The participants were 17 healthy term newborns or very young infants whose ages at the time of the first examination ranged from 1 to 24 days. The examiner held the tip of an index finger 20 to 30 cm in front of a participant's mouth, then suddenly moved it directly toward the mouth. Thirteen of the participants were also examined with the examiner's palm as the visual stimulus. The response was judged to be positive if clear mouth opening was elicited as the fingertip or palm was approaching the mouth.

RESULTS

In the examinations using a fingertip, the frequency of a positive response as to the total number of examinations in the different age groups within the first two months of life ranged between 43.9% and 48.8%, and precipitously decreased to 6.3% at two months of age. A positive response was not elicited from age three months. On the other hand, in the examinations using a palm, the frequency of a positive response was 5.0% in the newborns, and 6.7% in the infants aged between seven days and one month. A positive response was never obtained from two months of age.

CONCLUSION

This study demonstrated that visually guided mouth opening toward an approaching target exists in the human newborn. The eye-mouth associated movement may be controlled through rudimentary but functional visuomotor circuits in the brain interconnecting different cortices.

Assessing the Impact of Movement Consequences on the Development of Early Reaching in Infancy

Prior research on infant reaching has shown that providing infants with repeated opportunities to reach for objects aids the emergence and progression of reaching behavior. This study investigated the effect of movement consequences on the process of learning to reach in pre-reaching infants. Thirty-five infants aged 2.9 months at the onset of the study were randomly assigned to 1 of 3 groups. Two groups received a 14-day intervention to distinct reaching tasks: (1) in a contingent group, a toy target moved and sounded upon contact only, and (2) in a continuous group, the toy moved and sounded continuously, independent of hand-toy contact. A third control group did not receive any intervention; this group's performance was assessed only on 2 days at a 15-day interval. Results revealed that infants in the contingent group made the most progress over time compared to the two other groups. Infants in this group made significantly more overall contacts with the sounding/moving toy, and they increased their rate of visually attended target contacts relative to non-visually attended target contacts compared to the continuous and control groups. Infants in the continuous group did not differ from the control group on the number of hand-toy contacts nor did they show a change in visually attended target versus non-visually attended target contacts ratio over time. However, they did show an increase in movement speed, presumably in an attempt to attain the moving toy. These findings highlight the importance of contingent movement consequences as a critical reinforcer for the selection of action and motor learning in early development. Through repeated opportunities to explore movement consequences, infants discover and select movements that are most successful to the task-at-hand. This study further demonstrates that distinct sensory-motor experiences can have a significant impact on developmental trajectories and can influence the skills young infants will discover through their interactions with their surroundings.

Fetal Behavioural Responses to Maternal Voice and Touch

Background

Although there is data on the spontaneous behavioural repertoire of the fetus, studies on their behavioural responses to external stimulation are scarce.

Aim, Methods

The aim of the current study was to measure fetal behavioural responses in reaction to maternal voice; to maternal touch of the abdomen compared to a control condition, utilizing 3D real-time (4D) sonography. Behavioural responses of 23 fetuses (21st to 33rd week of gestation; N = 10 in the 2nd and N = 13 in the 3rd trimester) were frame-by-frame coded and analyzed in the three conditions.

Results

Results showed that fetuses displayed more arm, head, and mouth movements when the mother touched her abdomen and decreased their arm and head movements to maternal voice. Fetuses in the 3rd trimester showed increased regulatory (yawning), resting (arms crossed) and self-touch (hands touching the body) responses to the stimuli when compared to fetuses in the 2nd trimester.

Conclusion

In summary, the results from this study suggest that fetuses selectively respond to external stimulation earlier than previously reported, fetuses actively regulated their behaviours as a response to the external stimulation, and that fetal maturation affected the emergence of these differential responses to the environment.

Which way to take? Infants select an efficient path to their goal

In two experiments, we examined the development of the ability to select efficient means in order to attain a goal in 1.5- and 2-year-olds (N = 79) using a setup in which two paths led to a goal. One of the paths was shorter, and thus more efficient, than the other path. Experiment 1 showed a strong tendency in both age groups to choose the shorter path. In Experiment 2, the shorter path was initially blocked and became available only after infants repeatedly took the longer path. Children demonstrated increasing use of the more efficient path over time. The results of both experiments point to some abilities of efficient action selection in infants.

Evolutionary aspects of self- and world consciousness in vertebrates

Although most aspects of world and self-consciousness are inherently subjective, neuroscience studies in humans and non-human animals provide correlational and causative indices of specific links between brain activity and representation of the self and the world. In this article we review neuroanatomic, neurophysiological and neuropsychological data supporting the hypothesis that different levels of self and world representation in vertebrates rely upon (i) a “basal” subcortical system that includes brainstem, hypothalamus and central thalamic nuclei and that may underpin the primary (or anoetic) consciousness likely present in all vertebrates; and (ii) a forebrain system that include the medial and lateral structures of the cerebral hemispheres and may sustain the most sophisticated forms of consciousness [e.g., noetic (knowledge based) and autonoetic, reflective knowledge]. We posit a mutual, bidirectional functional influence between these two major brain circuits. We conclude that basic aspects of consciousness like primary self and core self (based on anoetic and noetic consciousness) are present in many species of vertebrates and that, even self-consciousness (autonoetic consciousness) does not seem to be a prerogative of humans and of some non-human primates but may, to a certain extent, be present in some other mammals and birds

Early gait development in human infants: Plasticity and clinical applications

In this paper we focus on how a developmental perspective on plasticity in the control of human movement can promote early therapy and improve gait acquisition in infants with developmental disabilities. Current knowledge about stepping development in healthy infants across the first year of life highlights strong plasticity, both in behavioral outcome and in underlying neuro-muscular activation. These data show that stepping, like other motor skills, emerges from the interaction between infant's maturation and the environment. This view is reinforced by showing that infants with different internal resources (like genetic disorder or neural tube defect) show unique developmental trajectories when supported on a treadmill, yet do respond. Moreover, we will show that their behavior can be improved by context manipulations (mostly sensory stimulation) or practice. Overall, plasticity in the neural, skeletal, and muscle tissues create new opportunities for optimizing early intervention by creatively tapping into the same developmental processes experienced by healthy infants.

Embodied intersubjective engagement in mother-infant tactile communication: a cross-cultural study of Japanese and Scottish mother-infant behaviors during infant pick-up

This study examines the early development of cultural differences in a simple, embodied, and intersubjective engagement between mothers putting down, picking up, and carrying their infants between Japan and Scotland. Eleven Japanese and ten Scottish mothers with their 6- and then 9-month-old infants participated. Video and motion analyses were employed to measure motor patterns of the mothers’ approach to their infants, as well as their infants’ collaborative responses during put-down, pick-up, and carry phases. Japanese and Scottish mothers approached their infants with different styles and their infants responded differently to the short duration of separation during the trial. A greeting-like behavior of the arms and hands was prevalent in the Scottish mothers’ approach, but not in the Japanese mothers’ approach. Japanese mothers typically kneeled before making the final reach to pick-up their children, giving a closer, apparently gentler final approach of the torso than Scottish mothers, who bent at the waist with larger movements of the torso. Measures of the gap closure between the mothers’ hands to their infants’ heads revealed variably longer duration and distance gap closures with greater velocity by the Scottish mothers than by the Japanese mothers. Further, the sequence of Japanese mothers’ body actions on approach, contact, pick-up, and hold was more coordinated at 6 months than at 9 months. Scottish mothers were generally more variable on approach. Measures of infant participation and expressivity indicate more active participation in the negotiation during the separation and pick-up phases by Scottish infants. Thus, this paper demonstrates a culturally different onset of development of joint attention in pick-up. These differences reflect cultures of everyday interaction.