Using a continuous index of laterality to determine how laterality is related to interhemispheric transfer and bimanual coordination in children

We sought to determine whether laterality is related to interhemispheric transfer and bimanual coordination during development. Children between 3 and 8 years of age were observed. In the first part of the experiment, we devised a continuous index to order the subjects according to their laterality. The laterality index included evaluation of hand and eye preference, and the right-left performance difference. In the second part of the experiment, we used this single index to determine whether laterality is related to interhemispheric transfer and bimanual coordination. Interhemispheric transfer was assessed by means of two tactile transfer tasks and one visuo-manual transfer task. We assessed bimanual coordination using the tapping task and the bimanual crank-rotation task. Results showed that right- and left-hand writers overlap on certain measures of laterality. They confirmed the improvement of interhemispheric transfer at around age 5 years, earlier progress in bimanual coordination with mirror than with parallel movements, and the existence of a relationship between visuo-manual interhemispheric transfer and bimanual coordination. The laterality index was not related to interhemispheric transfer, but it was related to the younger subjects' performance on the bimanual crank-rotation task: the less right handed, the better the bimanual coordination. In addition, on the same bimanual task, crossed hand-eye laterality was associated with better performance.     

Dorsal spinocerebellar tract neurons respond to contralateral limb stepping

Proprioceptive sensory information carried by spinocerebellar tracts provides a major input to the spinocerebellum, which has an important role in coordinating motor output for posture and locomotion. Until recently it was assumed that the information transmitted by the dorsal spinocerebellar tract (DSCT) was organized to represent single muscles or single joints in the ipsilateral hindlimb. Recent studies have shown, however, that DSCT activity represents global kinematic parameters of the hindlimb. We now present evidence that the DSCT neurons are also modulated by passive step-like movements of either hindlimb, implying they receive a bilateral sensory input. About two-thirds of 78 cells studied had significant responses to movements of the contralateral limb alone and about 70% responded differently to bipedal movements than to ipsilateral movement alone. The same basic behavior was observed in anesthetized, paralyzed cats and in unanesthetized, decerebrate cats, although decerebrate cats may have had larger responses on average. The results suggest that many DSCT cells may encode information about interlimb coordination. Electronic Publication     

The severity and nature of motor impairment in Asperger's syndrome: a comparison with specific developmental disorder of motor function

BACKGROUND: The aims of this study were to measure objectively the extent and severity of motor impairment in children with Asperger's syndrome and to determine whether the motor difficulties experienced by such children differed in any way from those classified as having a Specific Developmental Disorder of Motor Function (SDD-MF). Criteria derived from ICD 10-R were used to identify 11 children with Asperger's syndrome and a matched group of 9 children with a Specific Developmental Disorder of Motor Function. Children in both groups were required to have a verbal IQ of 80 or greater on the WISC IIIR. METHOD: The Autism Diagnostic Interview (Revised; Lord, Rutter, & LeCouteur, 1994) was used to identify features of AS in the first group and to exclude them in the latter. The Movement Assessment Battery for Children (Henderson & Sugden, 1992) provided a standardised test of motor impairment. A Gesture Test based on that by Cermak, Coster, and Drake (1980) was used to assess the child's ability to mime the use of familiar tools and to imitate meaningless sequences of movements. RESULTS: All the children with Asperger's syndrome turned out to meet our criterion for a diagnosis of motor impairment, five of the six most severely motor impaired children in the whole study being from this group. Performance of the Asperger group was also slightly poorer on the Gesture Test. The profile of performance on each test was examined in detail but no evidence of group differences in the pattern of impairment was found. CONCLUSIONS: This study is consistent with others suggesting a high prevalence of clumsiness in Asperger's syndrome. Our findings also attest to the widespread prevalence of motor impairment in developmental disorders and the problems such co-morbidity poses for attempts to posit discrete and functionally coherent impairments underlying distinct syndromes.     

Visuomanual coordination in childhood: adaptation to visual distortion

The aim of the experiment was to study the adaptive capacities of children to perform drawing movements while being visually perturbed. Children aged 5-11 years and a group of adults drew diamonds via information provided through a computer screen. The screen display was either upright or rotated 180 degrees. Results showed that the absence of direct vision of the hand yielded more perturbation in the youngest group of children compared to all other groups. In spite of some initial difficulty, all children reached accurate control after five trials. When faced with spatial rotations of the visual field, youngsters were again more perturbed than others. All children showed the same rate of adaptation to visual rotations, but they differed on adaptive strategies. Five- and 7-year-olds shifted to a feedforward mode of control consisting of the production of a rapid gesture, followed by error evaluation in order to correct their next movement. Older children were characterised by a progressive integration of reafferent visual and proprioceptive information. It resulted in an increase in duration of strokes and reduced speed, meaning enhanced on-line retrieval of information. However, 9-year-old children experienced more difficulty recuperating sensory information during movement than 11-year-olds, and kept using error feedback. Finally, visuomanual coordination in children aged 11 years, while slightly differing from that of adults, was not yet totally mature.     

Precision Grip Force Control of Older and Younger Adults, Revisited

This study revisited the hypothesis that older adults lose some ability to efficiently control precision grip force. A previous study demonstrated such a decrement in older adults' performance in a vertical lift and support maneuver. This study employed a similar paradigm in which dynamic forces were applied with a simulated hand tool while measuring grip force and force applied with the tool. Measures of grip force control reflected subjects' modulation of grip force in parallel with force transmitted with the tool and their scaling of the ratio of grip to applied force. Nine older (>65 years) and 9 younger (<65 years) subjects' grip force control measures were compared with emphasis on recruiting active older individuals for whom upper extremity usage was high in their daily life. No statistically significant age effects were found in either force control measure, suggesting a smaller age-related decrement than reported in a previous study.     

Bimanual organization of manipulative forces: evidence from erroneous feedforward programming of precision grip

The objective of the present study was to investigate grip-load force regulation during a bimanual lifting task with two hand-held objects. Various conditions were included during which the weight of one or both objects was changed in an unpredictable order every fourth trial. Results showed that force control of heavy weight movements preceded by light weight movements was not strongly influenced across trials. Conversely, force responses of light weight movements preceded by heavy weight movements were overestimated due to an augmented degree of grip force. However, successful updating of force output occurred after one trial. Furthermore, bimanual interactions between the grasping forces were observed, suggestive of a coordinative command that assimilated the individual response specifications. The latter also became apparent from a similar grip-load force ratio for both hands when the objects' physical properties had become predictable, independent of the forces that were produced according to the individual weight requirements. These data indicate that the grip-load force ratio is the controlled variable for bimanual manipulative behaviour.     

钴、铁、锰卟啉与含氮类药物轴向配位反应电化学性质研究

利用三电极体系研究了四（对 甲氧基苯基）卟啉钴（Ⅱ）,氯合四（间三甲基苯基）卟啉铁（Ⅲ）,氯合四（间三甲基苯基）卟啉锰（Ⅲ）分别与药物甲巯基咪唑,克霉唑和氨苯砜轴向配位反应的电化学性质,结果表明,轴向配位反应发生后,其金属卟啉的半波电位发生了改变．     

高碘酸银钾合成宏观反应动力学

建立了在强碱、强氧化条件下,由硝酸银合成高碘酸银钾的液固配合反应宏观动力学模型,推导了两种条件下的动力学方程式,并经实验验证。高碘酸根的初始浓度c0AL≤55.6 mmol/L时,反应为传质控制,动力学表达式为［1-(1-xB)1/2］·(1+110.7x1/2.04B)=t;当55.6 mmol/L≤c0AL≤139 mmol/L时,反应处于传质和反应阻力共存区,动力学表达式为100.6［1-(1-xB)1/2］·［1-(1-xB)1/1.51］=t。与实际数据相比较,两种情况下的动力学方程式均有良好的     

Pulmonary function in children with development coordination disorder

The purpose of this study was to compare pulmonary function in children with developmental coordination disorder (DCD) with children who are typically developing (TD), and also analyze possible gender differences in pulmonary function between these groups. The Movement ABC test was used to identify the movement coordination ability of children. Two hundred and fifty participants (90 children with DCD and 160 TD children) aged 9-10 years old completed this study. Using the KoKo spirometry, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV_1.0) were used to measure pulmonary function. The 800-m run was also conducted to assess cardiopulmonary fitness of children in the field. There was a significant difference in pulmonary function between TD children and those with DCD. The values of FVC and FEV_1.0 in TD children were significantly higher than in children with DCD. A significant, but low correlation (r = −0.220, p < .001) was found between total score on the MABC and FVC; similarly, a positive but low correlation (r = 0.252, p < .001) was found between total score on the MABC and the completion time of 800-m run. However, no significant correlation between FVC and the time of 800-m run was found (p > .05). Significant correlations between total score on the MABC and the completion time of the 800-m run (r = 0.352, p < .05) and between FVC and the time of 800-m run (r = −0.285, p < .05) were observed in girls with DCD but not boys with this condition. Based on the results of this study, pulmonary function in children with DCD was significantly lower than that of TD children. The field test, 800-m run, may not be a good indicator to distinguish aerobic ability between children with DCD and those who are TD. It is possible that poor pulmonary function in children with DCD is due to reduced physical activity in this population.     

Vestibular contribution to combined arm and trunk motion

Recent studies have shown that the hand-pointing movements within arm's reach remain invariant whether the trunk is recruited or not or its motion is unexpectedly prevented. This suggests the presence of compensatory arm-trunk coordination minimizing the deflections of the hand from the intended trajectory. It has been postulated that vestibular signals elicited by the trunk motion and transmitted to the arm motor system play a major role in the compensation. One prediction of this hypothesis is that vestibular stimulation should influence arm posture and movement during reaching. It has been demonstrated that galvanic vestibular stimulation (GVS) can influence the direction of pointing movements when body motion is restrained. In the present study, we analyzed the effects of GVS on trunk-assisted pointing movements. Subjects either moved the hand to a target or maintained a steady-state posture near the target, while moving the trunk forward with the eyes closed. When GVS was applied, the final position of the hand was deviated in the lateral and sagittal direction in both tasks. This was the result of two independent effects: a deviation of the trunk trajectory and a modification of the arm position relative to the trunk. Thus, the vestibular system might be directly involved not only in the control of trunk motion but also in the arm-trunk coordination during trunk-assisted reaching movements. Electronic Publication