The order of attentional focus instructions affects how postural control processes compensate for multisensory mismatch: a crossover study.

Directing attention during balance training can have an immediate and lasting impact on a patient's balance and ultimately decrease the risk of future falls. However, it is unclear how attention can best be utilized to improve postural control. The current study uses a 2 × 2 crossover design to investigate the potential impact of receiving multiple verbal instructions during a single session of sensorimotor control testing for balance. Twenty-eight healthy adults were tasked to balance on a rocker board while immersed in virtual reality (VR). The VR created a multisensory mismatch between visual VR motion and body motion. The strength of the relationship between visual motion and body motion was measured to assess visual dependence. Alpha and theta frequency bands in electroencephalography (EEG) recordings were also analyzed to identify potential neural correlates of visual dependence and postural stability. Participants were randomized into two groups: one group was first instructed to keep the board leveled (external focus) and then instructed to keep both feet leveled (internal focus) to help maintain stability. The other group was given these two instructions in reverse order. Analyses focused on time, instruction, and group effects from receiving multiple instructions. Results revealed that when participants are given external focus first, and internal focus second, they are more likely to demonstrate lower visual dependence and better postural stability throughout the entire session than participants given internal focus first and external focus second. However, channel-level EEG analyses did not reveal differences between the groups. Current findings suggest that the order of attentional focus instructions may influence how the postural control system resolves sensory incongruence during a single testing session.

Anticipation across modalities in children and adults: Relating anticipatory alpha rhythm lateralization, reaction time, and executive function.

The development of the ability to anticipate-as manifested by preparatory actions and neural activation related to the expectation of an upcoming stimulus-may play a key role in the ontogeny of cognitive skills more broadly. This preregistered study examined anticipatory brain potentials and behavioral responses (reaction time; RT) to anticipated target stimuli in relation to individual differences in the ability to use goals to direct action (as indexed by measures of executive function; EF). A cross-sectional investigation was conducted in 40 adults (aged 18-25 years) and 40 children (aged 6-8 years) to examine the association of changes in the amplitude of modality-specific alpha-range rhythms in the electroencephalogram (EEG) during anticipation of lateralized visual, tactile, or auditory stimuli with inter- and intraindividual variation in RT and EF. Children and adults exhibited contralateral anticipatory reductions in the mu rhythm and the visual alpha rhythm for tactile and visual anticipation, respectively, indicating modality and spatially specific attention allocation. Variability in within-subject anticipatory alpha lateralization (the difference between contralateral and ipsilateral alpha power) was related to single-trial RT. This relation was more prominent in adults than in children, and was not apparent for auditory stimuli. Multilevel models indicated that interindividual differences in anticipatory mu rhythm lateralization contributed to the significant association with variability in EF, but this was not the case for visual or auditory alpha rhythms. Exploratory microstate analyses were undertaken to cluster global field power (GFP) into a distribution-free temporal analysis examining developmental differences across samples and in relation to RT and EF. Anticipation is suggested as a developmental bridge construct connecting neuroscience, behavior, and cognition, with anticipatory EEG oscillations being discussed as quantifiable and potentially malleable indicators of stimulus prediction.

Genes, genomes, and developmental process.

The view advanced by Madole & Harden falls back on the dogma of a gene as a DNA sequence that codes for a fixed product with an invariant function regardless of temporal and spatial contexts. This outdated perspective entrenches the metaphor of genes as static units of information and glosses over developmental complexities.

The impact of external and internal focus of attention on visual dependence and EEG alpha oscillations during postural control.

BACKGROUND: The ability to maintain upright posture requires successful integration of multiple sensory inputs (visual, vestibular, and somatosensory). When one or more sensory systems become unreliable, the postural control system must "down-weight" (or reduce the influence of) those senses and rely on other senses to maintain postural stability. As individuals age, their ability to successfully reweight sensory inputs diminishes, leading to increased fall risk. The present study investigates whether manipulating attentional focus can improve the ability to prioritize different sensory inputs for postural control. METHODS: Forty-two healthy adults stood on a balance board while wearing a virtual reality (VR) head-mounted display. The VR environment created a multisensory conflict amongst the different sensory signals as participants were tasked with maintaining postural stability on the balance board. Postural sway and scalp electroencephalography (EEG) were measured to assess visual weighting and cortical activity changes. Participants were randomized into groups that received different instructions on where to focus their attention during the balance task. RESULTS: Following the instructions to direct attention toward the movement of the board (external focus group) was associated with lower visual weighting and better balance performance than when not given any instructions on attentional focus (control group). Following the instructions to direct attention towards movement of the feet (internal focus group) did not lead to any changes in visual weighting or balance performance. Both external and internal focus groups exhibited increased EEG alpha power (8-13 Hz) activity over the occipital cortex as compared to the control group. CONCLUSIONS: Current results suggest that directing one's attention externally, away from one's body, may optimize sensory integration for postural control when visual inputs are incongruent with somatosensory and vestibular inputs. Current findings may be helpful for clinicians and researchers in developing strategies to improve sensorimotor mechanisms for balance.

Exploring developmental changes in infant anticipation and perceptual processing: EEG responses to tactile stimulation.

There is an increasing interest in alpha-range rhythms in the electroencephalogram (EEG) in relation to perceptual and attentional processes. The infant mu rhythm has been extensively studied in the context of linkages between action observation and action production in infancy, but less is known about the mu rhythm in relation to cross-modal processes involving somatosensation. We investigated differences in mu responses to cued vibrotactile stimulation of the hand in two age groups of infants: From 6 to 7 months and 13 to 14 months. We were also interested in anticipatory neural responses in the alpha frequency range prior to tactile stimulation. Tactile stimulation of infants' left or right hand was preceded by an audiovisual cue signaling which hand would be stimulated. In response to the tactile stimulus, infants demonstrated significant mu desynchronization over the central areas contralateral to the hand stimulated, with higher mu peak frequency and greater contralateral mu desynchronization for older infants. Prior to the tactile stimulus, both age groups showed significant bilateral alpha desynchronization over frontocentral sites, which may be indicative of generalized anticipation of an upcoming stimulus. The findings highlight the potential of examining the sensorimotor mu rhythm in the context of infant attentional development.

Individual differences in anticipatory mu rhythm modulation are associated with executive function and processing speed.

There is increasing interest in the role of brain oscillations in the regulation and control of behavior. The current study examined the relations between specific cognitive abilities and changes in brain oscillatory activity during anticipation of, and in response to, tactile stimulation of the hand. The oscillation of interest was the sensorimotor mu rhythm (8-14 Hz) at central electrode sites. The electroencephalogram (EEG) was recorded during a task in which a visuospatial cue directed adults (N = 40) that a tactile stimulus would be delivered to their left or right hand. Lateralized changes in mu power following tactile stimulation were associated with reaction time to the tactile stimulus. The extent of a contralateral anticipatory reduction in mu power during the 500 ms before the tactile stimulus was associated with performance on a separate processing speed task. Changes in ipsilateral mu power during anticipation of the tactile stimulus were associated with performance on a flanker task and were marginally correlated with performance on a card sort task. Regression analyses further indicated the specificity of these relations to anticipatory changes in mu power. In summary, mu rhythm modulation during anticipation of tactile stimulation to a specific bodily location was related to a broad measure of processing speed and to variability in the broader ability to regulate behavior in a goal-directed manner. Implications are discussed in terms of the foundational role of anticipatory attention in cognitive processes and the utility of selective attention to the body as an index of attentional control more broadly.

Body maps in the infant brain: implications for neurodevelopmental disabilities.

This review and synthesis discusses recent work that has utilized brain imaging methods, such as the electroencephalogram (EEG) and magnetoencephalogram, to provide insights into the ways that the body is represented in the infant brain. One aspect of body representation concerns somatotopic maps of the body surface in somatosensory cortex. A good deal is known about the properties of these maps in adults, but there has been relatively little developmental work. Recent studies have provided new insights into the organization of infant neural body maps and have laid the foundations for examining their plasticity in relation to behavioral development. Other work has suggested that neural body maps may be involved in the registration of correspondences between self and other, with implications for early social development. Here, body representations are discussed in the context of preterm birth and autism spectrum disorder, providing novel perspectives relevant to developmental medicine and child neurology. WHAT THIS PAPER ADDS: ●Somatotopic body maps develop prenatally through intrinsic and activity-dependent mechanisms. ●There is increasing interest in understanding postnatal plasticity in body maps. ●Body representations may be involved in the registration of preverbal, interpersonal relationships.

Neural representations of the body in 60-day-old human infants.

The organization of body representations in the adult brain has been well documented. Little is understood about this aspect of brain organization in human infancy. The current study employed electroencephalography (EEG) with 60-day-old infants to test the distribution of brain responses to tactile stimulation of three different body parts: hand, foot, and lip. Analyses focused on a prominent positive response occurring at 150-200 ms in the somatosensory evoked potential at central and parietal electrode sites. The results show differential electrophysiological signatures for touch of these three body parts. Stimulation of the left hand was associated with greater positive amplitude over the lateral central region contralateral to the side stimulated. Left foot stimulation was associated with greater positivity over the midline parietal site. Stimulation of the midline of the upper lip was associated with a strong bilateral response over the central region. These findings provide new insights into the neural representation of the body in infancy and shed light on research and theories about the involvement of somatosensory cortex in infant imitation and social perception.

Neuropsychology of Human Body Parts: Exploring Categorical Boundaries of Tactile Perception Using Somatosensory Mismatch Responses.

The focus of the current study is on a particular aspect of tactile perception: categorical segmentation on the body surface into discrete body parts. The MMN has been shown to be sensitive to categorical boundaries and language experience in the auditory modality. Here we recorded the somatosensory MMN (sMMN) using two tactile oddball protocols and compared sMMN amplitudes elicited by within- and across-boundary oddball pairs. Both protocols employed the identity MMN method that controls for responsivity at each body location. In the first protocol, we investigated the categorical segmentation of tactile space at the wrist by presenting pairs of tactile oddball stimuli across equal spatial distances, either across the wrist or within the forearm. Amplitude of the sMMN elicited by stimuli presented across the wrist boundary was significantly greater than for stimuli presented within the forearm, suggesting a categorical effect at an early stage of somatosensory processing. The second protocol was designed to investigate the generality of this MMN effect, and involved three digits on one hand. Amplitude of the sMMN elicited by a contrast of the third digit and the thumb was significantly larger than a contrast between the third and fifth digits, suggesting a functional boundary effect that may derive from the way that objects are typically grasped. These findings demonstrate that the sMMN is a useful index of processing of somatosensory spatial discrimination that can be used to study body part categories.

Touching lips and hearing fingers: effector-specific congruency between tactile and auditory stimulation modulates N1 amplitude and alpha desynchronization.

Understanding the interactions between audition and sensorimotor processes is of theoretical importance, particularly in relation to speech processing. Although one current focus in this area is on interactions between auditory perception and the motor system, there has been less research on connections between the auditory and somatosensory modalities. The current study takes a novel approach to this omission by examining specific auditory-tactile interactions in the context of speech and non-speech sound production. Electroencephalography was used to examine brain responses when participants were presented with speech syllables (a bilabial sound /pa/ and a non-labial sound /ka/) or finger-snapping sounds that were simultaneously paired with tactile stimulation of either the lower lip or the right middle finger. Analyses focused on the sensory-evoked N1 in the event-related potential and the extent of alpha band desynchronization elicited by the stimuli. N1 amplitude over fronto-central sites was significantly enhanced when the bilabial /pa/ sound was paired with tactile lip stimulation and when the finger-snapping sound was paired with tactile stimulation of the finger. Post-stimulus alpha desynchronization at central sites was also enhanced when the /pa/ sound was accompanied by tactile stimulation of the lip. These novel findings indicate that neural aspects of somatosensory-auditory interactions are influenced by the congruency between the location of the bodily touch and the bodily origin of a perceived sound.

Infant brain responses to felt and observed touch of hands and feet: an MEG study.

There is growing interest concerning the ways in which the human body, both one's own and that of others, is represented in the developing human brain. In two experiments with 7-month-old infants, we employed advances in infant magnetoencephalography (MEG) brain imaging to address novel questions concerning body representations in early development. Experiment 1 evaluated the spatiotemporal organization of infants' brain responses to being touched. A punctate touch to infants' hands and feet produced significant activation in the hand and foot areas of contralateral primary somatosensory cortex as well as in other parietal and frontal areas. Experiment 2 explored infant brain responses to visually perceiving another person's hand or foot being touched. Results showed significant activation in early visual regions and also in regions thought to be involved in multisensory body and self-other processing. Furthermore, observed touch of the hand and foot activated the infant's own primary somatosensory cortex, although less consistently than felt touch. These findings shed light on aspects of early social cognition, including action imitation, which may build, at least in part, on infant neural representations that map equivalences between the bodies of self and other.

Neural body maps in human infants: Somatotopic responses to tactile stimulation in 7-month-olds.

A large literature has examined somatotopic representations of the body in the adult brain, but little attention has been paid to the development of somatotopic neural organization in human infants. In the present study we examined whether the somatosensory evoked potential (SEP) elicited by brief tactile stimulation of infants' hands and feet shows a somatotopic response pattern at 7months postnatal age. The tactile stimuli elicited a prominent positive component in the SEP at central sites that peaked around 175ms after stimulus onset. Consistent with a somatotopic response pattern, the amplitude of the response to hand stimulation was greater at lateral central electrodes (C3 and C4) than at the midline central electrode (Cz). As expected, the opposite pattern was obtained to foot stimulation, with greater peak amplitude at Cz than at C3 and C4. These results provide evidence of somatotopy in human infants and suggest that the developing body map can be delineated using readily available methods such as EEG. These findings open up possibilities for further work investigating the organization and plasticity of infant body maps.

What makes Simon Says so difficult for young children?

Compared with conceptually similar response inhibition tasks, the game of Simon Says is particularly challenging for young children. However, possible reasons for this difference have not been systematically investigated. Here we tested the relative influence of two dissociable characteristics of the standard Simon Says task: receiving both inhibition and activation commands from the same experimenter and seeing the experimenter perform the movement along with the commands. A sample of 74 children (mean age = 55 months) were randomly assigned to complete one of five possible tasks. Four of the five tasks were variations of Simon Says involving combinations of one or two experimenters and the presence versus absence of the experimenter's movements. The fifth task was Bear-Dragon, a commonly used executive function task in which one experimenter employed two puppets to give action commands to children. Analyses revealed that children's performance was significantly worse on the one-person Simon Says tasks compared with the two-person tasks and the Bear-Dragon task. The presence of the experimenters' movements alongside their commands did not have a significant effect on children's performance. The requirement to respond to one person who is changing how different rules apply to similar actions appears to be an important determinant of the difficulty of Simon Says for young children. In terms of implications, inconsistency in how an adult applies rules to children's actions may be a detrimental social influence on the development of cognitive control during early childhood.

Electrophysiological responses to digit stimulation in a tactile oddball paradigm.

Sensory memory traces are assessed via oddball paradigms in which deviant (infrequent) stimuli are interspersed into a string of standard (frequent) stimuli. Once a memory trace for the standard is established, the deviant spurs a change detection response measured via the resulting event related potential (ERP). Response magnitude is sensitive to the differences in stimuli properties or categories and influenced by individual experience. The goal of the present study was to use ERPs to test the relation between individual digits in the somatosensory cortex and the extent to which digit representations are influenced by individual differences in experience such as independent mobility and playing video games. The present study of 60 undergraduates utilized a passive tactile oddball paradigm, stimulating the thumb, middle, and little fingers. The oddball paradigm was fully matched with each digit serving as the standard and deviant. A temporal principal component analysis (tPCA) identified factors that matched three a priori ERP components: N80, somatosensory mismatch negativity (sMMN), and P300. Analyses confirmed the anticipated differences between standards and deviants and provided some support for prior ERP work suggesting the thumb is in a different functional category than the other digits. Independent control of individual digits (such as the little finger) was positively related to only one aspect of the ERP (P3a) while video game experience was not associated with ERP differences. Cumulatively, these results provide a more nuanced examination of tactile oddball paradigms and how ERP methods can shed light on the relations between different digits.

Coping with complexity: developmental systems and multilevel analyses in developmental psychopathology.

Developmental psychopathology is not characterized by adherence to one specific theory but instead serves as an organizational framework in which research is driven by a number of key assumptions. In the developmental psychopathology approach, two primary assumptions emphasize the importance of systems thinking and the utility of multilevel analyses. As will be illustrated here, these emphases are inextricably linked: a systems approach necessitates a multilevel approach, such that a level of organization must bring coherence to a level of mechanisms. Given this assumption, coming to an integrative understanding of the relation between levels is of central importance. One broad framework for this endeavor is relational developmental systems, which has been proposed by certain theorists as a new paradigm for developmental science. The implications of embracing this framework include the potential to connect developmental psychopathology with other approaches that emphasize systems thinking and that take an integrative perspective on the problem of levels of analysis.

Ethical considerations in child-robot interactions.

Social robots hold promise in augmenting education, rehabilitative care, and leisure activities for children. Despite findings suggesting various benefits of social robot use in schools, clinics, and homes, stakeholders have voiced concerns about the potential social and emotional effects of children engaging in long-term interactions with robots. Given the challenges of conducting large long-term studies of child-robot interaction (CRI), little is known about the impact of CRI on children's socio-emotional development. Here we summarize the literature on predictions and expectations of teachers, parents, therapists, and children regarding the effects of CRI on children's socio-emotional functioning and skill building. We then highlight the limited body of empirical research examining how CRI affects children's social behavior and emotional expression, and we provide a summary of available questionnaires for measuring socio-emotional constructs relevant to CRI. We conclude with design recommendations for research studies aimed at better understanding the effects of CRI, before social robots become ubiquitous. This review is relevant to researchers, educators, roboticists, and clinicians interested in designing and using social robots with developmental populations.

Neural correlates of action observation and execution in 14-month-old infants: an event-related EEG desynchronization study.

There is increasing interest in neurobiological methods for investigating the shared representation of action perception and production in early development. We explored the extent and regional specificity of EEG desynchronization in the infant alpha frequency range (6-9 Hz) during action observation and execution in 14-month-old infants. Desynchronization during execution was restricted to central electrode sites, while action observation was associated with a broader desynchronization across frontal, central, and parietal regions. The finding of regional specificity in the overlap between EEG responses to action execution and observation suggests that the rhythm seen in the 6-9 Hz range over central sites in infancy shares certain properties with the adult mu rhythm. The magnitude of EEG desynchronization to action perception and production appears to be smaller for infants than for adults and older children, suggesting developmental change in this measure.

Does motor interference arise from mirror system activation? The effect of prior visuo-motor practice on automatic imitation.

Action perception may involve a mirror-matching system, such that observed actions are mapped onto the observer's own motor representations. The strength of such mirror system activation should depend on an individual's experience with the observed action. The motor interference effect, where an observed action interferes with a concurrently executed incongruent action, is thought to arise from mirror system activation. However, this view was recently challenged. If motor interference arises from mirror system activation, this effect should be sensitive to prior sensorimotor experience with the observed action. To test this prediction, we measured motor interference in two groups of participants observing the same incongruent movements. One group had received brief visuo-motor practice with the observed incongruent action, but not the other group. Action observation induced a larger motor interference in participants who had practiced the observed action. This result thus supports a mirror system account of motor interference.

The Shared Origins of Embodiment and Development.

As a domain of study centering on the nature of the body in the functioning of the individual organism, embodiment encompasses a diverse array of topics and questions. One useful organizing framework places embodiment as a bridge construct connecting three standpoints on the body: the form of the body, the body as actively engaged in and with the world, and the body as lived experience. Through connecting these standpoints, the construct of embodiment shows that they are not mutually exclusive: inherent in form is the capacity for engagement, and inherent in engagement is a lived perspective that confers agency and meaning. Here, we employ this framework to underscore the deep connections between embodiment and development. We begin with a discussion of the origins of multicellularity, highlighting how the evolution of bodies was the evolution of development itself. The evolution of the metazoan (animal) body is of particular interest, because most animals possess complex bodies with sensorimotor capacities for perceiving and acting that bring forth a particular sort of embodiment. However, we also emphasize that the thread of embodiment runs through all living things, which share an organizational property of self-determination that endows them with a specific kind of autonomy. This realization moves us away from a Cartesian machine metaphor and instead puts an emphasis on the lived perspective that arises from being embodied. This broad view of embodiment presents opportunities to transcend the boundaries of individual disciplines to create a novel integrative vision for the scientific study of development.

Social learning of action-effect associations: Modulation of action control following observation of virtual action's effects.

A core assumption of ideomotor theory is that learned bidirectional associations between actions and their effects enable agents to select and initiate actions by anticipating their sensory consequences. Although the acquisition of bidirectional action-effect (A-E) associations built on the experience of one's own movements has received considerable empirical support, the available evidence for A-E learning through the observation of others' actions and their effects remains limited. In two experiments, we tested whether A-E associations could be acquired through social learning in an experimental setup involving observation of virtual actions. In an acquisition phase, participants repeatedly observed finger movements on a screen, and each movement was consistently followed by a specific effect tone. In the subsequent test phase, tones were presented as imperative stimuli in a reaction-time task. In both experiments, reaction times were shorter when tones required the same response with which they had been linked in the preceding observation phase, compared with when they required a different response, revealing the impact of A-E associations acquired through observation. Similar results were obtained whether the movements observed during the acquisition phase were spatially aligned (Experiment 1) or not (Experiment 2) with participants' responses in the test phase, ruling out the possibility that the results merely reflect spatial compatibility effects. Our findings add new evidence for an acquisition of A-E associations through observation. Importantly, we generalize this acquisition process to the observation of virtual actions. These findings further confirm effect-based action control, as proposed by ideomotor theory.