Effects of attentional prioritisation on the temporal and spatial components of an interlimb circle-drawing task

Effect of verbal cues on the coupling and stability of anti-phase bimanual coordination pattern in children with probable developmental coordination disorder

The study of the emergence and stability of bimanual and interlimb coordination patterns in children with Developmental Coordination Disorder (DCD) has shown that they encounter greater difficulties in coupling their limbs compared to typically developing (TD) children. Verbal cues have been identified as strategies to direct children's attention to more relevant task information, thus potentially improving motor performance. Consequently, this study investigated the effect of providing verbal cues on the execution of bimanual tasks in children with and without probable DCD. Twenty-eight children aged 9-10, matched by age and gender, were divided into two groups: pDCD [n = 14] and TD. The children performed bilateral trajectory movements with both hands (horizontal back-and-forth), holding a pen on a tablet, in anti-phase (180°) coordination pattern, in two conditions: No cues and Verbal cues. In the last condition, children received verbal cues to maintain the anti-phase pattern even with an increase in hand oscillation frequency. Relative phase and variability of relative phase between the hands were calculated for analysis of pattern coupling and stability. Hand cycles, movement amplitude, and tablet pressure force were calculated to analyze pattern control parameters. All these variables were compared between groups and conditions. The results indicated that despite the pDCD group showing greater variability in the anti-phase coordination pattern compared to the TD group, both groups performed better in the Verbal cues than the No cues condition. Furthermore, the pDCD group exhibited more hand movement cycles and applied greater pressure force compared to the TD group, suggesting different motor control strategies during the bimanual task. It is suggested that the use of verbal cues during bimanual task execution improves children's performance, potentially by promoting interaction between attention, as a cognitive function, and intrinsic coordination dynamics, thereby reducing variability in the perceptual-motor system.

Expert monitoring and verbal feedback as sources of performance pressure

The influence of monitoring-pressure and verbal feedback on the performance of the intrinsically stable bimanual coordination patterns of in-phase and anti-phase was examined. The two bimanual patterns were produced under three conditions: 1) no-monitoring, 2) monitoring-pressure (viewed by experts), and 3) monitoring-pressure (viewed by experts) combined with verbal feedback emphasizing poor performance. The bimanual patterns were produced at self-paced movement frequencies. Anti-phase coordination was always less stable than in-phase coordination across all three conditions. When performed under conditions 2 and 3, both bimanual patterns were performed with less variability in relative phase across a wide range of self-paced movement frequencies compared to the no-monitoring condition. Thus, monitoring-pressure resulted in performance stabilization rather than degradation and the presence of verbal feedback had no impact on the influence of monitoring pressure. The current findings are inconsistent with the predictions of explicit monitoring theory; however, the findings are consistent with studies that have revealed increased stability for the system's intrinsic dynamics as a result of attentional focus and intentional control. The results are discussed within the contexts of the dynamic pattern theory of coordination, explicit monitoring theory, and action-focused theories as explanations for choking under pressure.

Potential explanation of limb combination performance differences for two-limb coordination tasks

Rhythmic two-limb coordinated movements in the sagittal plane are variable and inaccurate when the movements are in the opposite direction as compared with those in the same direction (directional constraint). The magnitude of directional constraint depends on the particular limb combination. It is prominent in ipsilateral hand-foot coordination, but minimal in bimanual hand coordination. The reason for such differences remains unclear. In this study, we investigated the possible mechanisms underlying the production of the difference that depend on limb combination. Subjects performed two-limb rhythmic coordinated movements either in the same or in the opposite direction for three separate limb combinations (bilateral hands, contralateral hand and foot, and ipsilateral hand and foot). For each combination two different tasks were performed. In the first condition, subjects actively moved two limbs (active condition). Second, subjects actively moved one limb in coordination with a passively moved limb (passive condition). In the active condition, the directional constraint was dependent upon the limb combination, as reported in previous studies; the directional constraint was quite prominent in ipsilateral combinations, intermediate in contralateral combinations, and minimal for bilateral combination. However, differences in the directional constraint did not depend on limb combination for any combination in the passive conditions which apparently utilized closed-loop control. In other word, the difference depending on limb combination disappeared when control strategies become uniformly closed-loop. Thus, we speculate that the control strategy utilized depends on limb combination in the active condition. Additionally, different mechanisms other than closed-loop control also would have influence depending on the particular limb combination. This may result in differences in performance depending upon the limb combination.

Aging and motor inhibition: a converging perspective provided by brain stimulation and imaging approaches

The ability to inhibit actions, one of the hallmarks of human motor control, appears to decline with advancing age. Evidence for a link between changes in inhibitory functions and poor motor performance in healthy older adults has recently become available with transcranial magnetic stimulation (TMS). Overall, these studies indicate that the capacity to modulate intracortical (ICI) and interhemispheric (IHI) inhibition is preserved in high-performing older individuals. In contrast, older individuals exhibiting motor slowing and a declined ability to coordinate movement appear to show a reduced capability to modulate GABA-mediated inhibitory processes. As a decline in the integrity of the GABA-ergic inhibitory processes may emerge due to age-related loss of white and gray matter, a promising direction for future research would be to correlate individual differences in structural and/or functional integrity of principal brain networks with observed changes in inhibitory processes within cortico-cortical, interhemispheric, and/or corticospinal pathways. Finally, we underscore the possible links between reduced inhibitory functions and age-related changes in brain activation patterns.

Factors that determine directional constraint in ipsilateral hand-foot coordinated movements

In performing simultaneous rhythmic movements of the ipsilateral hand and foot, there are differences in the level of stability between same directional (stable) and opposite directional (unstable) movements. This is the directional constraint. In this study, we investigated three factors ("interaction in efferent process," "interaction of afferent signals," and "error correction") proposed to underlie for the directional constraint. We compared the performance of three tasks: (1) coordination of actively moved ipsilateral hand and foot, (2) active hand movement in coordination with passively moved foot, (3) active hand movement not coordinated with a passively moved foot. In each task, both same and opposite directional movements were executed. There was no difference between performance estimated with success rate for the first and second task. The directional constraint appeared in both tasks. Thus, the interaction in efferent processes, which was shown to be responsible for the directional constraint in bimanual coordination, was not involved with the directional constraint of ipsilateral hand-foot coordination. The directional constraint did not appear in the third task, which suggested that "interaction of afferent signals" also had no contribution. These results indicated that "error correction" must be the most critical of these factors for mediating the directional constraint in ipsilateral hand-foot coordinated movements.

Co-variation between graphic pattern stability and attentional cost: a clue for the difficulty to produce handwritten traces

Attentional cost incurred for generating handwritten graphic patterns was investigated using a classic dual-task procedure, in which a concurrent reaction time (RT) task was used as an index of the attentional cost incurred by the primary graphic task. Eight right-handed adults had to trace graphic patterns, characterized by a 0°, 45°, 90°, 135° or 180° relative phase and corresponding to shapes ranging from lines to ellipses to circles, while responding by a key press as fast as possible to an auditory signal. The results evidenced a strong and significant correlation between the stability of the produced pattern and the associated attentional cost. The amplitude of the minor and major axes of the produced ellipsoids decreased with the increase of movement frequency, as expected by nonlinear models of oscillatory pattern generation. These findings pave the way to the study for the (coordinative) processes for letter (mal)formation in cursive handwriting.

Effect of Different External Attention of Focus Instruction on Learning of Golf Putting Skill

The effect of different sources of external attentional focus on learning a motor skill was assessed in the present study. 30 students (12 men, 18 women) participated voluntarily and were divided, according to type of external focus, into target, club swing, and target-club swing groups. The task was a golf putting skill. The target focus group attended to the target (hole), the club swing focus group attended to the execution of the club's swing, and the target-club swing focus group attended to both. All participants performed 50 trials of the putting skill in the acquisition phase and 10 trials in the 24-hr. delayed retention phase. The dependent variable was the error in the putting skill measured as the distance from the hole to the ball after each strike. Results showed the target-club swing focus group had better scores in the acquisition and retention phases than the other groups. It was concluded that external focus instruction helped the learners to integrate target cue with action cue and is more effective in skill learning than other external-focus instructions. These results support the claims of ecological psychology theorists concerning the effects of external focus of attention.

Spatial error detection in rapid unimanual and bimanual aiming movements

According to closed-loop accounts of motor control, movement errors are detected by comparing sensory feedback to an acquired reference state. Differences between the reference state and the movement-produced feedback results in an error signal which serves as a basis for a correction. The current study assessed whether error detection is less accurate when feedback from both hands must be analyzed compared to one hand and if error detection is more accurate in longer movements compared to shorter movements. 36 college-age participants (26 women and 10 men) performed a rapid aiming movement of varying distances with one hand or both hands simultaneously. Participants verbally estimated the distance moved on all trials before knowledge of results was given. Error detection was measured by the correlation and the mean absolute difference between the actual and estimated distance. Error detection was not more accurate for the longer movements, and participants underestimated errors in all conditions. Strong positive correlations were shown for both unimanual and bimanual aiming tasks, suggesting that two streams of sensory information can be processed concurrently.

Age-related differences in inhibitory processes during interlimb coordination

The study examined the neurophysiological correlates of age-related changes in the coordination of hand and foot movements. Young and older adults (N=30) performed cyclical isodirectional and non-isodirectional hand-foot movements with contralateral and ipsilateral limb combinations. Motor evoked potentials (MEPs) and silent period durations following transcranial magnetic stimulation (TMS) were measured from the right extensor carpi radialis (ECR) muscle during the interlimb coordination tasks. Older adults demonstrated lower coordination stability than younger adults, particularly when performing non-isodirectional movements with ipsilateral limbs. For all coordination tasks, MEP amplitude was lower in older compared with young participants. Young adults showed significantly longer silent period durations when the coordination pattern involved ipsilateral limbs than during contralateral limb coordination. In contrast, silent period durations did not differ between contralateral and ipsilateral limb coordination in older adults. These results suggest that deterioration in motor performance with advancing age may be associated with a decreased ability to modulate inhibitory function.

Distinct ways of timing movements in bimanual coordination tasks: contribution of serial correlation analysis and implications for modeling

Bimanual coordination dynamics have been conceived as the outcome of a global coordinative system, and coordination stability properties and theories of underlying processes have often been generalized over various bimanual tasks. In unimanual timing tasks it has been shown that different timing processes are involved according to tasks, yielding distinctive correlation properties in the within-hand temporal patterns. In this study we compare unimanual with bimanual, tapping with oscillation, and self-paced with externally paced tasks, and we analyze the correlation properties of temporal patterns at both the component level and the coordinative level. Results show that the distinctive signatures of event-based versus emergent, and self-paced versus synchronization timing control known from unimanual tasks persist in the corresponding bimanual coordination tasks. Accordingly, we argue that these different timing processes, and related temporal patterns at the component level, constitute a task-dependent background on which coordination builds. One direct implication of these results is that the bimanual coordination paradigm should be considered multifaceted and not governed by some unitary generic principle. We discuss the need to assess the relationship between temporal patterns at the component level and the collective level, and to integrate serial (long-range) correlation properties into bimanual coordination models. Finally, we test whether the architectures of current bimanual coordination models can account for the experimentally observed serial correlations.