Kicking coordination captures differences between full-term and premature infants with white matter disorder

This study explores the relation of white matter disorder (WMD) to intralimb coordination patterns in premature infants with very low birth weight (VLBW). We specifically measured the temporal-spatial characteristics of intralimb coordination patterns of the legs. Three groups of infants were compared at one month corrected age (CA): 10 premature infants born VLBW and WMD (PTWMD), 10 premature infants born VLBW without WMD (PT) and 10 full term infants (FT). Using kinematic variables, we discriminate among VLBW infants with WMD from the two comparison groups. Infants born with WMD maintain patterns of tight coupling among leg joints (all flexion or all extension) while PT and FT term infants have begun to decouple leg joints by this age (combinations of flexion with extension). The coupling pattern is captured through joint correlations, discrete relative phase, and phase plane portraits. The PTWMD infants also demonstrate aberrant patterns of coordination evident through both temporal and spatial characteristics of the kicks. This is the first evidence that movement disorder associated with brain lesions can be identified and quantified with kinematic variables as early as one month of age.     

Interlimb coordination in prosthetic walking: effects of asymmetry and walking velocity

The present study focuses on interlimb coordination in walking with an above-knee prosthesis using concepts and tools of dynamical systems theory (DST). Prosthetic walkers are an interesting group to investigate from this theory because their locomotory system is inherently asymmetric, while, according to DST, coordinative stability may be expected to be reduced as a function of the asymmetry of the oscillating components. Furthermore, previous work on locomotion motivated from DST has shown that the stability of interlimb coordination increases with walking velocity, leading to the additional expectation that the anticipated destabilizing effect of the prosthesis-induced asymmetry may be diminished at higher walking velocities. To examine these expectations, an experiment was conducted aimed at comparing interlimb coordination during treadmill walking between seven participants with an above-knee prosthesis and seven controls across a range of walking velocities. The observed gait patterns were analyzed in terms of standard gait measures (i.e., absolute and relative swing, stance and step times) and interlimb coordination measures (i.e., relative phase and frequency locking). As expected, the asymmetry brought about by the prosthesis led to a decrease in the stability of the coordination between the legs as compared to the control group, while coordinative stability increased with increasing walking velocity in both groups in the absence of a significant interaction. In addition, the 2:1 frequency coordination between arm and leg movements that is generally observed in healthy walkers at low walking velocities was absent in the prosthetic walkers. Collectively, these results suggest that both stability and adaptability of coordination are reduced in prosthetic walkers but may be enhanced by training them to walk at higher velocities.     

Coordination deficits on the ipsilesional side after unilateral stroke: the effect of practice on nonisodirectional ipsilateral coordination

Previous studies have identified motor deficits on the ipsilesional side of patients recovering from a cerebro-vascular accident (CVA), including deficits in interlimb coordination. In the present study, unilateral stroke patients and a control group of healthy age-matched controls performed nonisodirectional coordination of the ipsilateral limbs across two days of practice with feedback. Findings revealed that control subjects were already quite successful at initiation of practice but further improved the coordination pattern across both days. The group of CVA patients also showed some improvement but problems with coordination of the ipsilateral limb segments persisted across practice. Variability in both timing and amplitude of both limb segments did improve with practice in both groups but these measures remained significantly higher in the CVA patients. Even though isodirectional and nonisodirectional coordination of the ipsilateral limb segments are normally considered to be part of the intrinsic motor repertoire, the present study suggests that nonisodirectional ipsilesional limb coordination poses considerable difficulties for CVA patients that are not easily overcome with feedback-assisted practice.     

Spontaneous emotional coordination of first-born dizygotic twins and singletons with their mothers in early infancy

We compare matching of facial expressions of emotion, completion of the positive valence of emotional expression, attunement of emotional intensity, and non-matching of emotion, in engagements with their mothers of firstborn dizygotic twins and of singletons. Nine twins and nine singletons were video-recorded at home in spontaneous face-to-face interactions from the second to the sixth month after birth. Microanalysis of infant and maternal facial expressions of emotion revealed qualitative and quantitative differences that indicate that engagements with twins had more frequent and more accurate emotional matching and attunements compared to those with singletons. Singletons displayed more emotional completion and non-matching reactions. Expressions of matching for pleasure and interest followed different developmental patterns in the two kinds of dyads. These results are discussed in relation to the theory of innate affective intersubjectivity. Differences may shed light on the relationship between sharing early life with a twin, and development of self-other awareness.     

Differential changes in the development of motor coordination and executive functions in children with motor coordination impairments

Cognitive and motor coordination skills of children with and without motor coordination impairments were examined with a one-year follow-up investigation. Initially, children were between 4 and 6 years old. Age-appropriate tests of executive functions (updating, switching, inhibition, interference control), motor coordination (the Movement Assessment Battery for Children-2) and fitness (the Körperkoordinations-Test für Kinder) were administered in two consecutive years. Several background variables (age, socioeconomic status, medical support, clinical interventions, leisure activities) and potential moderators (nonverbal intelligence, reaction time, visual perception) were controlled. The matched sample consisted of 48 control children and 48 children with motor coordination impairments. The children’s executive functions dramatically improved during the one-year period. With regard to motor coordination performance, half of the impaired children caught up to the control children’s level (“remission group”), while the remaining half showed no improvement (“persisting group”). Compared to the persisting group, the children in the remission group showed markedly better interference control at both measurement points. The correlation between executive functions and motor coordination is significant in the persisting group, but not in the remission group. The results of the study are discussed in the light of the role of executive functions, especially inhibition processes, for the automatization of motor coordination tasks.     

The control of amplitude and direction in a bimanual coordination task

Bimanual coordination requires task-specific control of the spatial and temporal characteristics of the movements of both hands. The present study focused on the spatial relationship between hand movements when their amplitude and direction were manipulated. In the experiment in question, participants were instructed to draw two lines simultaneously. These two lines were instructed to be drawn in mirror symmetric or perpendicular directions of each other while the length was instructed to be the same or different. The coordinative quality of amplitude control was compared when the task required symmetric and asymmetric bimanual spatial coordination patterns. Results showed that the amplitude accuracy decreased when different amplitudes and/or directions had to be generated simultaneously. The coordinative quality of direction was also compared when the task required symmetric and asymmetric bimanual spatial coordination patterns. Unlike amplitude, the direction accuracy was largely independent of coordination symmetry/asymmetry of direction or amplitude. The results suggest that the coordinative quality of amplitude control does not only interfere with amplitude asymmetry, but it also interferes with direction asymmetry. Moreover, in bimanual coordination amplitude control is more vulnerable to the influence of direction control demands than vice versa.     

Conversation, gaze coordination, and beliefs about visual context

Conversation is supported by the beliefs that people have in common and the perceptual experience that they share. The visual context of a conversation has two aspects: the information that is available to each conversant, and their beliefs about what is present for each other. In our experiment, we separated these factors for the first time and examined their impact on a spontaneous conversation. We manipulated the fact that a visual scene was shared or not and the belief that a visual scene was shared or not. Participants watched videos of actors talking about a controversial topic, then discussed their own views while looking at either a blank screen or the actors. Each believed (correctly or not) that their partner was either looking at a blank screen or the same images. We recorded conversants' eye movements, quantified how they were coordinated, and analyzed their speech patterns. Gaze coordination has been shown to be causally related to the knowledge people share before a conversation, and the information they later recall. Here, we found that both the presence of the visual scene, and beliefs about its presence for another, influenced language use and gaze coordination.     

Cerebral lateralization and general intelligence: gender differences in a transcranial Doppler study

The present study evaluated cerebral lateralization during Raven's progressive matrices (RPM) paradigm in female and male subjects. Bilateral simultaneous transcranial Doppler (TCD) ultrasound was used to measure mean blood flow velocities (MBFV) in the right and left middle cerebral arteries (MCAs) in 24 (15 females and 9 males) right-handed normal subjects. The female subjects used a left hemisphere strategy, while males used a right hemisphere strategy to successfully solve RPM tasks. This implies that general intelligence is associated with neural systems within one hemisphere that are accessible to a variety of cognitive processes.     

Categorization in early infancy and the continuity of development

Arguments and evidence are presented for the conclusion that the young infant's perceptually based categorical representations for natural kinds - animals in this case - are the basis for their mature conceptual counterparts. In addition, it is argued that conceptual development is continuous in nature and without the need for special developmental processes. A consideration of the development of the syllabic, segmental, and featural categories of phonology shows a more complex pattern of change - one marked by both continuities and discontinuities in the representations themselves and the processes that produce them.     

Influence of perceived emotion and gender on social motor coordination

Theorists have long postulated that facial properties such as emotion and sex are potent social stimuli that influence how individuals act. Yet extant scientific findings were mainly derived from investigations on the prompt motor response upon the presentation of affective stimuli, which were mostly delivered by means of pictures, videos, or text. A theoretical question remains unaddressed concerning how the perception of emotion and sex would modulate the dynamics of a continuous coordinated behaviour. Conceived in the framework of dynamical approach to interpersonal motor coordination, the present study aimed to address this question by adopting the coupled-oscillators paradigm. Twenty-one participants performed in-phase and anti-phase coordination with two avatars (male and female) displaying three emotional expressions (neutral, happy, and angry) at different frequencies (100% and 150% of the participant's preferred frequency) by executing horizontal rhythmic left-right oscillatory movements. Time to initiate movement (TIM), mean relative phase error (MnRP), and standard deviation of relative phase (SDRP) were calculated as indices of reaction time, deviation from the intended pattern of coordination, and coordination stability, respectively. Results showed that in anti-phase condition at 150% frequency, MnRP was lower with the angry and the female avatar. In addition, coordination was found to be more stable with the male avatar than the female one when both displaying neutral emotion. But the happy female avatar was found to elicit more stable coordination than the neutral female avatar. These results implied that individuals are more relaxed to coordinate with the female than the male, and the sensorimotor system becomes more flexible to coordinate with an angry person. It is also suggested social roles influence how people coordinate, and individuals attend more to interact with a happy female. In sum, the present study evidenced that social perception is embodied in the interactive behaviour during social interaction.     

The development of spatial understanding in infancy

This paper examines the development of spatial understanding between 8 and 24 months. In particular, it examines whether young infants code changes in the position of an object or themselves in geographic or egocentric terms. The infants sat in a baby chair which was attached to a circular table in such a way that either the infant could be rotated around the edge of the table or the table-top itself could be rotated. Rotation of infant or table could be performed independently or simultaneously. Infants were shown an object which was then hidden under one of either two or three identical cups sitting on the table. Before the infant was allowed to search for the toy, either the table, the infant, or both were rotated, a procedure which resulted in an invisible displacement of the object in terms of geographical and/or egocentric spatial position. Rotations of 60, 90, 120, and 180° were used. Three groups of infants were tested, one cross-sectional (12–24 months), one longitudinal (12–24 months), and one consisting of a group of infants already known to be accelerated in object concept development (8–20 months). The cross-sectional results indicated that egocentric responding continues well into the second half of the second year of life. Even with fortnightly exposure to the tasks, egocentric responding was still evident in some longitudinal babies as late as 19 months. The results of the accelerated group suggest that acceleration through the sequence of object concept development facilitates development of spatial understanding in a wider sense, that is, in the sense of understanding the interrelation of positions in space. The implications of these results for competing theories of the source of object concept errors are discussed.     

Central and peripheral vision in early infancy

The size of the effective visual field during the first weeks of life is found to depend on two factors: It increases with age, but it contracts in the face of competition from ongoing activity such as fixation of a central stimulus or non-nutritive sucking.     

Trust-suspicion and gender differences in interpersonal functioning

Responses on self-report questionnaires (Study 1) and in a dyadic game (Study 2) were observed to investigate relationships of trust-suspicion (T-S), locus of control (I-E), and situational contingencies to styles of interpersonal functioning. Generalized T-S predicted cooperative/competitive interactional choices among the male college student samples (p ? .01). However, T-S predicted females' interpersonal behaviors only when they were in a reactive, defensive position. T-S did not relate to actual behaviors when females were allowed to select/initiate cooperative or competitive exchanges. Situational rules (p ? .025) and I-E (p ? .01) predicted all subjects' behaviors when in a choice, but not defensive, position.     

Cross-linguistic differences in early semantic and cognitive development

In a longitudinal study, the early semantic and cognitive development of 11 Koreanspeaking and 12 English-speaking children was recorded. Three types of cognitive abilities, object-permanence, means-ends problem solving, and categorization, and three related semantic abilities, disappearance words, success/failure words, and a naming spurt emerged at about the same time in English speakers. However, categorization and the naming spurt were significantly delayed relative to other abilities in the Korean speakers. In absolute terms, categorization and the naming spurt emerged later in Korean speakers than in English speakers, and means-ends abilities and success/failure words emerged earlier in Korean speakers than in English speakers. In a cross-sectional study of 18 Korean speakers and 30 English speakers, the Korean-speaking mothers consistently emphasized actions, and the English-speaking mothers consistently emphasized names. The Korean-speaking children were consistently delayed in categorization and advanced in means-ends abilities relative to the English speakers. These findings suggest that differences in linguistic input may affect cognitive development.     

Gender differences in empathy: the role of the right hemisphere

The relationship between activation of the right cerebral hemisphere (RH) and empathy was investigated. Twenty-two men and 73 women participated by completing a chimeric face task and empathy questionnaire. For the face task, participants were asked to pick which of the two chimeric faces looked happier. Both men and women were significantly more likely to say the chimera with the smile to their left was happier, suggesting activation of the RH. As expected, men scored significantly lower than women on the empathy questionnaire, p = .003. A correlation was found between RH activation on the face task and empathy for women only, p = .037, suggesting a possible neural basis for gender differences in empathy.     

Age-related differences in the brain areas outside the classical language areas among adults using category decision task

Older adults perform much like younger adults on language. This similar level of performance, however, may come about through different underlying brain processes. In the present study, we evaluated age-related differences in the brain areas outside the typical language areas among adults using a category decision task. Our results showed that similar activation patterns were found in classical language processing areas across the three age groups although regional lateralization indices in Broca’s and Wernicke’s areas decreased with age. The greatest differences, however, among the three groups were found primarily in the brain areas not associated with core language functioning including the hippocampus, middle frontal gyrus, ventromedial frontal cortex, medial superior parietal cortex and posterior cingulate cortex. Therefore, the non-classical language areas may exhibit an age-related difference between three age groups while the subjects show a similar activation pattern in the core, primary language processing during a semantic decision task.     

Hemifacial preferences for the perception of emotion and attractiveness differ with the gender of the one beheld

Though the left cheek appears more emotive, perceptions of attractiveness vary with gender. For the first time, this study assessed the relationship between perceptions of emotion (happiness) and attractiveness in naturalistic photographic portraits. One hundred ninety-two participants (63 male; 129 female) viewed pairs of left and right cheek poses, and made a forced-choice decision indicating which image appeared (a) more emotive and (b) more attractive (order counterbalanced). Half the images were mirror-reversed to control for perceptual biases. Results indicated a striking gender difference: for males, the left cheek appears both more emotive and more attractive; for females, preferences are subject to stronger perceptual influences, with the right cheek bias for emotion and attractiveness reversing to a left cheek bias when images are mirror-reversed. These findings suggest that if you want to show the world your “best side”, men should lead with the left but for women, the right cheek is right.     

The use of realistic and mechanical hands in the rubber hand illusion,and the relationship to hemispheric differences

Embodiment, as measured through the rubber-hand illusion (RHI), depends on the similarity between object to be embodied and part of the body it replaces. We compared a fake hand similar to a real hand, and one matched in size but made of wires (mechanical). Left and right versions were tested to investigate whether the effect of appearance was stronger in the left hand. We found that the mechanical hand induced embodiment, though to a reduced degree relative to the realistic hand (N = 120). Left and right versions of the mechanical hand did not differ in strength of the illusion. However, with the left realistic hand there was a stronger relationship between drift (an objective measure of the illusion) and agreement on the questionnaire (subjective experience). With the mechanical hand, objective and subjective measures were unrelated. We discuss the results in relation to factors that influence the RHI and hemispheric differences.