Neural modeling and imaging of the cortical interactions underlying syllable production

This paper describes a neural model of speech acquisition and production that accounts for a wide range of acoustic, kinematic, and neuroimaging data concerning the control of speech movements. The model is a neural network whose components correspond to regions of the cerebral cortex and cerebellum, including premotor, motor, auditory, and somatosensory cortical areas. Computer simulations of the model verify its ability to account for compensation to lip and jaw perturbations during speech. Specific anatomical locations of the model's components are estimated, and these estimates are used to simulate fMRI experiments of simple syllable production.     

An especial skill: Support for a learned parameters hypothesis

We tested the ‘learned parameters’ hypothesis as an explanation of the ‘especial skill effect’. Outcome attainment and movement kinematics were recorded for 10 expert and 10 novice players performing basketball free-throw shots at five distances (11-19 ft) with a regular and heavy weight basketball. As predicted, experts performed better than expected relative to the regression equation at the 15 ft, free-throw line with the regular basketball, supporting the ‘especial skill effect’. This effect was not present for the experts when shooting with the heavy ball. Novices did not show an advantage at the free-throw line when performing with either ball. Although the outcome attainment scores support the ‘learned parameters’ hypotheses, kinematic analysis failed to identify differences in the movement pattern for the especial skill, suggesting that these skills (i.e., shooting at different distances) are not governed by separate motor programs.     

Connectionism and Self: James,Mead, and the Stream of Enculturated Consciousness

William James conceptualized I, the self as subject as a stream of consciousness. When this conception is augmented with George Herbert Mead's view of self as a radically socialized and enculturated process, a result is the James-Mead model of dynamic self as a stream of enculturated consciousness. In this paper, we argue that connectionism is best suited to theorize this challenging notion. Based on the view that a connectionist model should describe psychological processes that carry out psychological functions grounded in a biological living system, we propose the I-SELF (Imitative and Sequence Learning Functional) model, which is designed to capture the temporal dynamics of a stream of consciousness whose content can be acquired via symbolically mediated social interaction with others in society. We identify four implications of the James-Mead model of dynamic self (embodiment, narrative and self, individual and collective self, and culture and self), and report computer simulations to show the utility of I-SELF in conceptualizing the dynamic self-processes in the contemporary social psychological literature. Theoretical and metatheoretical implications of the connectionist approach to self are discussed.     

Perceptual Estimates of Motor Skill Proficiency Are Constrained by the Stability of Coordination Patterns

This study demonstrated that motor skill proficiency ratings are constrained by the same order parameter dynamics that constrain action production and action perception processes. Participants produced rhythmic actions simulated by an animated stick figure of the human arm. The primary finding was that participants’ proficiency ratings covaried most with relative phase (φ) variability compared to mean relative phase. In-phase (φ = 0°) was produced with the least variability and received the highest proficiency rating, whereas the patterns φ = ±150° were attempted with the most variability and received the lowest proficiency ratings. A temporal delay in attempting to produce the animated pattern had a large impact on produced relative phase, yet had little impact on the proficiency ratings. Proprioceptive processes provide individuals information on motor skill proficiency. The lead or lag motion of the hand to forearm segment of the animated arm was identified consistently through visual processes and revealed asymmetries in the mapping of visual input to motor output. The results are consistent with concepts from the dynamic pattern theory of coordination and are discussed with regard to relative phase as an informational variable that constraints the perception-action system across many levels.     

Sit-to-stand movement in children: A longitudinal study based on kinematics data

Although the ability to stand from a seated posture is relevant for clinical practice, there are few studies investigating the process of acquisition and refinement of the motor components involved in sit-to-stand movement (STS) in children. Therefore, this longitudinal study aims to describe kinematic characteristics of the STS movement in children from 12 to 18 months, and also to investigate the relationship between changes in STS movement and childrens’ daily-life mobility. Ten healthy children were evaluated at 12,13,14,15 and 18 months of age. A motion analysis system was used to measure total duration of STS movement and angular movements of each joint, and frequencies of successful and unsupported STS were obtained. The Pediatric Evaluation of Disability Inventory was used to assess childrens’ daily-life mobility. Results showed that children tend to increase the frequency of successful trials over the months by reducing the total duration and decreasing peak ankle dorsiflexion and trunk flexion during STS. Children also started to stand up from chair with decreased trunk flexion angle among ages. At the end of the STS, we observed decreases in trunk flexion and knee flexion over age. Furthermore, kinematic characteristics that reflect improvements in STS movement are related to better performance of functional skills and decreased level of assistance provided by the caregiver in daily-life mobility of younger children. However, the strength of these associations decreases from 14 months of age onwards.     

Mirroring,imitation, identification: the sense of self in relation to the mother's internal world

The phenomenon of neonatal imitation, and the use of mutual imitation by mother and baby in the service of attunement, are considered in relation to psychoanalytic theories of mirroring, imitation and identification. Material from infant observation and from the treatment of two children on the autistic spectrum is discussed in terms of the suggestion that developmental imitation implies a perceived position of balance between the external baby and the mother's supposed internal occupant. This is seen as making possible introjective identification and assimilation, with the enrichment of the sense of identity, in contrast to the kind of imitation involving mimicry, in which adhesive or projective identification may be operative.     

A behavioural experiment in virtual reality to verify the role of action function in space coding

Neurophysiological data indicate that the reachable peripersonal space and the unreachable extrapersonal space are represented in segregated parietofrontal circuits and that when the unreachable space becomes reachable because of tool use, it is automatically coded by the network selective for peripersonal space. Here we directly tested the role of action's consequences in space coding. Thirty-eight participants bisected lines at either a reachable distance (60 cm) or unreachable distance (120 cm) using either a laser pointer or laser cutter. The laser cutter but not the laser pointer had an action consequence; the line broke into two pieces. The results showed that distance moderated the effect of action. At an unreachable distance, the mean bisection point was closer to the centre when participants used the laser cutter compared to when they used the laser pointer. There were no differences at a reachable distance (60 cm). This result suggests that the space in which the individual may determine a physical consequence is categorized as peripersonal space, independently from its actual distance from the individual's body.     

Correlation of motor skill,mental rotation,and working memory in 3- to 6-year-old children

A relationship between motor processes and mental rotation has been suggested by current research; however, the influence of working memory on this relationship has not yet been determined. Therefore, a correlation between motor tests, paper–pencil and chronometric mental rotation tests, and working memory tests were conducted in 3- to 6-year-old children. A stepwise multiple-regression showed that 55.5% of the variance was explained by the working memory tests: digit span forward and Corsi forward. This indicates that working memory and executive functions may play an important role in mental rotation and motor processes.     

Early and persistent motor difficulties in infants at-risk of developing autism spectrum disorder: A prospective study

Analyses were conducted in order to investigate motor development in younger siblings of children diagnosed with autism spectrum disorder (ASD). Infants at familial risk and low risk of developing ASD were tested longitudinally between the ages of 7 and 36 months. Data were analysed from motor scales on the Mullen Scales of Early Learning and the Vineland Adaptive Behaviour Scales at each age point. Significantly lower motor scores in at-risk infants were evident from the age of 7 months compared to the low-risk group. Infants who were later diagnosed with ASD demonstrated significantly poorer Fine Motor skills at 36 months than at-risk infants without any developmental difficulties. In addition, Gross Motor scores were highly correlated across the two measures for low-risk infants and infants who later developed ASD. Early motor difficulties may be an early indicator of a number of neurodevelopmental disorders, including ASD.