ObjectivesConscious engagement in movement control can influence motor performance. In most cases, the left hemisphere of the brain plays an important role in verbal-analytical processing and reasoning, so changes in the balance of hemispheric activation may influence conscious engagement in movement. Evidence suggests that unilateral hand contractions influence hemispheric activation, but no study has investigated whether there is an associated effect of hand contractions on verbal-analytical processing during motor performance. This study utilized psychophysiological (and behavioural) measures to examine whether pre-performance unilateral hand contraction protocols change verbal-analytical engagement during motor performance.DesignA repeated measures crossover design was employed.MethodsTwenty-eight participants completed three hand contraction protocols in a randomised order: left-, right- and no-hand contractions. Electroencephalography (EEG) measures of hemispheric asymmetry were computed during hand contractions. A golf putting task was conducted after each protocol. EEG connectivity between sites overlying the left verbal-analytical temporal region (T7) and the motor planning region (Fz) was computed for the 3 sec prior to movement initiation. Additionally, electrocardiography (ECG) and electromyography (EMG) signals were analysed 6 sec prior to movement initiation until 6 sec after. Golf putting performance (distance from the target) and putter swing kinematics were measured.ResultsContralateral hemisphere activity was revealed for the left-hand and right-hand contraction conditions. During motor planning, the left-hand contraction protocol led to significantly lower T7-Fz connectivity, and the right-hand contraction protocol led to significantly higher T7-Fz connectivity than the other conditions. EMG, ECG and kinematic measures did not differ as a function of condition. Importantly, T7-Fz connectivity mediated the relationship between hand squeezing and motor performance (distance from the target).ConclusionThe EEG results suggest that pre-performance unilateral hand contractions influence the extent of verbal-analytical engagement during motor planning, which in turn influences motor performance. However, the hand contractions did not influence cardiac activity, muscle activity or kinematics. 相似文献
ObjectivesThis study examined how learning a dance choreography with different teaching pedagogies and different cognitive challenge influenced the development of working memory capacity and motor competence in primary school children.DesignRandomised-controlled trial.MethodsEighty primary school children (8.8 ± 0.7 years old; 61% females) were recruited and randomly assigned to two experimental groups – a high-cognitive and a low-cognitive group – and a control group. The two experimental groups practiced dance for 7 weeks, twice a week, learning a choreography, while the control group participated in the school standard PE curriculum. In the high-cognitive group, the dance teachers limited visual demonstrations and encouraged children to memorise and recall movement sequences to increase the cognitive challenge.ResultsWhile the pre-to post-test improvements did not statistically differ between experimental groups, the analysis showed that the high-cognitive group statistically improved their working memory capacity (p < 0.01; d = 0.51), while the low-cognitive (p = 0.04; d = 0.48) and control groups did not (p = 0.32; d = 0.17). All three groups improved their motor competence from pre-to post-test, and there was a significant group*time effect (p < 0.01, ηp2 = 0.13) with the high-cognitive group showing larger improvement than the control.ConclusionsThe results of this study provide initial support that dance practice coupled with a high cognitive challenge could improve working memory capacity and motor competence in children; however, the difference between groups was not statistically significant, and future research is necessary to examine the generalization of this finding. 相似文献
Integrity of both cerebral hemispheres is required to control in-phase or anti-phase coupling of ipsilateral hand and foot oscillations, as shown by the impairment of these tasks when performed on the healthy side of hemiplegic patients. On this basis, coupling of hand–foot movements was analysed in a right-handed subject (ME) who underwent a total resection of the corpus callosum. Oscillations of the prone hand and foot, paced by a metronome at different frequencies, as well as EMG activity in extensor carpi radialis (ECR) and tibialis anterior (TA) muscles were analysed by measuring the average phase difference between the hand and foot movements and EMG cycles.
ME performed in-phase movements (right-hand extension coupled to right-foot dorsal flexion) at frequencies up to 3 Hz, though the hand cycle progressively lagged the foot cycle as the frequency increased. At 3 Hz the hand lag reached −142° (as compared to about 25° in healthy subjects). The lag increased even further after application of an inertial load to the hand, reaching 180° at 1.8 Hz (about 50° in healthy subjects). ME's hand lag is caused by the lack of any anticipatory reaction in hand movers. In contrast to healthy subjects, which activate the ECR earlier than the TA when the frequency increases, ME activated the ECR later than TA at all frequencies higher than 0.9 Hz.
Anti-phase movements (hand extension coupled to foot plantar flexion) were performed only upto 1 Hz in unloaded conditions. At 0.6 Hz, movements were in tight phase-opposition (3°), but at 1 Hz, the hand lag reached −34° because of a delayed ECR activation. After hand loading ME was unable to couple movements in anti-phase. In contrast, normal subjects maintain a tight anti-phase coupling up to 2.0 Hz, both with an unloaded or loaded hand. Similar deficits were observed by ME when performing in-phase and anti-phase coupling on the left side, as well as when he was blindfolded.
In normal subjects, an anticipated muscular activation of hand movers compensates for hand loading. Since this compensation must depend on monitoring the hand delay induced by loading, the absence in ME of such compensatory reaction suggests that callosal division had apparently compromised the mechanisms sustaining feedback compensation for differences in the biomechanical limb properties. They also confirm and reinforce the idea that elaboration of the afferent message, aiming at controlling the phase of the movement association, needs the co-operation of both cerebral hemispheres. 相似文献
The question of independently controlled components in the act of reaching and grasping has attracted interest experimentally and theoretically. Data from 35 studies were recently found consistent with simulated kinematic finger and thumb trajectories optimised for minimum jerk. The present study closely reproduces those trajectories using a discrete-time model based on minimum acceleration. That model was further used to generate two-dimensional trajectories for finger and thumb to reach and grasp an elliptical object with varying position and/or orientation. Orthogonalisation of these four trajectories revealed one degree of freedom when direction of reach was constant and two degrees of freedom when direction of reach varied, irrespective of object distance and orientation. These simulations indicate that reach and grasp movements contain redundancy that is removable by formation of task-dependent synergies. As skilled movement can be planned and executed in a low dimension workspace, control of these independent components lessens central workload. 相似文献
This is a case study of a family with a child (age eight) with reactive attachment disorder and the subsequent individual and family therapy. Treatment of choice for the child was Eye Movement Desensitization and Reprocessing (EMDR) and supportive educational counseling for the parents and family. Qualitative evaluation of the process demonstrated that the parents observed an instant change in the child's attitude. The child reported that she felt better about family, school, and truthfulness, and stated about the therapy: It opened a window for me. A 12-month evaluation demonstrated continued positive effects. 相似文献
This study examined the role of global processing speed in mediating age increases in auditory memory span in 5- to 13-year-olds. Children were tested on measures of memory span, processing speed, single-word speech rate, phonological sensitivity, and vocabulary. Structural equation modeling supported a model in which age-associated increases in processing speed predicted the availability of long-term memory phonological representations for redintegration processes. The availability of long-term phonological representations, in turn, explained variance in memory span. Maximum speech rate did not predict independent variance in memory span. 相似文献
A range of possible predictors of arithmetic and reading were assessed in a large sample (N=162) of children between ages 7 years 5 months and 10 years 4 months. A confirmatory factor analysis of the predictors revealed a good fit to a model consisting of four latent variables (verbal ability, nonverbal ability, search speed, and phonological memory) and two manifest variables (digit comparison and phoneme deletion). A path analysis showed that digit comparison and verbal ability were unique predictors of variations in arithmetic skills, whereas phoneme deletion and verbal ability were unique predictors of variations in reading skills. These results confirm earlier findings that phoneme deletion ability appears to be a critical foundation for learning to read (decode). In addition, variations in the speed of accessing numerical quantity information appear to be a critical foundation for the development of arithmetic skills. 相似文献
Two new tests for a model for the response times on pure speed tests by Rasch (1960) are proposed. The model is based on the
assumption that the test response times are approximately gamma distributed, with known index parameters and unknown rate
parameters. The rate parameters are decomposed in a subject ability parameter and a test difficulty parameter. By treating
the ability as a gamma distributed random variable, maximum marginal likelihood (MML) estimators for the test difficulty parameters
and the parameters of the ability distribution are easily derived. Also the model tests proposed here pertain to the framework
of MML. Two tests or modification indices are proposed. The first one is focused on the assumption of local stochastic independence,
the second one on the assumption of the test characteristic functions. The tests are based on Lagrange multiplier statistics,
and can therefore be computed using the parameter estimates under the null model. Therefore, model violations for all items
and pairs of items can be assessed as a by-product of one single estimation run. Power studies and applications to real data
are included as numerical examples. 相似文献