Perceived Occurrence of the Second of Two Closely Spaced Stimuli in a Long Movement

A 75-deg. movement of the arm in the vertical plane was used to examine the conscious perception of the apparent time of occurrence of a reversal signal S₂. A marked perceptual delay was found whether S₂ occurred during or after the reaction time to the first stimulus. This finding was consistent with Henry’s memory drum theory of neuromotor response, as well as with the efference theory of conscious perception proposed by Festinger and associates.     

Working memory load moderates late attentional bias in social anxiety

The vigilance–avoidance hypothesis suggests that socially anxious individuals attempt to detect signs that they are being evaluated (vigilance) and subsequently direct attention away from such stimuli (avoidance). Although extensive evidence supports vigilance, data concerning subsequent avoidance is equivocal. Drawing from models of attention, the current study hypothesised that working memory load moderates late attentional bias in social anxiety such that avoidance occurs if working memory load is low, and difficulty disengaging attention occurs if working memory load is high. Forty-one undergraduates (19 socially anxious; 22 non-anxious controls) completed a dot-probe task with emotional (happy and disgust) and neutral facial expressions and a concurrent n-back task. Results supported the hypothesis such that socially anxious subjects demonstrated avoidance of disgust faces when working memory load was absent, but had difficulty disengaging attention during high working memory load. Theoretical implications and directions for future research are discussed.     

The neuronal basis of bimanual coordination: recent neurophysiological evidence and functional models

Recent physiological studies of the neuronal processes underlying bimanual movements provide new tests for earlier functional models of bimanual coordination. The recently acquired data address three conceptual areas: the generalized motor program (GMP), intermanual crosstalk and dynamic systems models. To varying degrees, each of these concepts has aspects that can be reconciled with experimental evidence. The idea of a GMP is supported by the demonstration of abstract neuronal motor codes, e.g. bimanual-specific activity in motor cortex. The crosstalk model is consistent with the facts that hand-specific coding also exists and that interactions occur between the motor commands for each arm. Uncrossed efferent projections may underlie crosstalk on an executional level. Dynamic interhemispheric interactions through the corpus callosum may provide a high-level link at the parametric programming level, allowing flexible coupling and de-coupling. Flexible neuronal interactions could also underlie adaptive large-scale systems dynamics that can be formalized within the dynamic systems theory approach.

The correspondence of identified neuronal processes with functions of abstract models encourages the development of realistic computational models that can predict bimanual behavior on the basis of neuronal activity.     

The interplay of attention and bimanual coordination dynamics

Despite their common origin, studies on motor coordination and on attentional load have developed into separate fields of investigation, bringing out findings, methods, and theories which are diverse if not mutually exclusive. Sitting at the intersection of these two fields, this article addresses the issue of behavioral flexibility by investigating how intention modifies the stability of existing patterns of coordination between moving limbs. It addresses the issue, largely ignored until now, of the attentional cost incurred by the central nervous system (CNS) in maintaining a coordination pattern at a given level of stability, in particular under different attentional priority requirements. The experimental paradigm adopted in these studies provides an original mix of a classical measure of attentional load, namely, reaction time, and of a dynamic approach to coordination, most suitable for characterizing the dynamic properties of coordinated behavior and behavioral change. Findings showed that central cost and pattern stability covary, suggesting that bimanual coordination and the attentional activity of the CNS involved in maintaining such a coordination bear on the same underlying dynamics. Such a conclusion provides a strong support to a unified approach to coordination encompassing a conceptualization in terms of information processing and another, more recent framework rooted in self-organization theories and dynamical systems models     

Interpersonal coordination tendencies and perception of visual information for decision-making in futsal

This study investigated how futsal players visually perceived information on angular interpersonal coordination relations, between available sources such as nearest defender, goalkeeper position and ball, when deciding to shoot at goal. Experienced players (n = 180) participated in eighteen, video-recorded futsal matches, during which 32 participants wore an eye tracking device. Forty-five sequences of play were selected and edited from the moment a teammate passed the ball to the shooter, until the moment a shot was undertaken. Independent variables included the angle connecting the shooter to their closest defender and goalkeeper, and it’s rate of change (velocity and variability) during performance. Then eye tracking system (TOBII PRO) was used to examine gaze patterns of shooters during task performance. Findings revealed that: (i) futsal players adapted their gaze patterns differently between key information sources when shooting confirmed as: their closest defender, goalkeeper, ball, and court floor; and (ii), the ball was the information source which was most fixated on, regardless of the characteristics of interpersonal coordination tendencies that emerged when shooting. These findings can be interpreted as evidence of functional perceptual behaviours used to regulate actions needed to ensure precise contact with the ball when shooting at goal. Further, adaptations of fixation patterns, varied between marking defender, goalkeeper, and ball, may provide functional postural orientation to facilitate a successful shot at goal.     

Effects of unintentional coordination on attentional load

The goal of this study was to evaluate the impact of unintentional (spontaneous) coordination on high attentional visual load. More precisely, we wondered whether such coordination could free up some attentional resources and help improve performance in other more demanding attentional tasks. An experiment was performed in which participant attentional allocation was challenged by performing three tasks simultaneously while simultaneously being induced to unintentional entrain to an environmental rhythm. The first task was an interception task associated with a Stroop test to increase their attentional load. The second task was a reaction time test to alarms in different modalities (auditory, visual and bimodal) which was used to assess participant attentional load. The third task was a motor task in which participants were asked to swing their legs at a preferred frequency. The interface background brightness intensity was either synchronized in real time using a bidirectional coupling to participant leg movement or the background brightness was not changing at all. Our results on the reaction time task demonstrated that participants exhibited better reaction times for alarms in the bimodal condition than in the auditory condition and lastly for the visual condition. Also, participants exhibited a lower reaction time to alarms when the background brightness was synchronizing with their leg regardless the alarm modality. Overall, our study suggests a beneficial effect of unintentional environmental coordination on attentional resource allocation and highlights the importance of bidirectionality in interaction.     

Coupling of postural and manual tasks in expert performers

The purpose of this study was to investigate the integration of bimanual rhythmic movements and posture in expert marching percussionists. Participants (N = 11) performed three rhythmic manual tasks [1:1, 2:3, and 2:3-F (2:3 rhythm played faster at a self-selected tempo)] in one of three postures: sitting, standing on one foot, and standing on two feet. Discrete relative phase, postural time-to-contact, and coherence analysis were used to analyze the performance of the manual task, postural control, and the integration between postural and manual performance. Across all three rhythms, discrete relative phase mean and variability results showed no effects of posture on rhythmic performance. The complexity of the manual task (1:1 vs. 2:3) had no effect on postural time-to-contact. However, increasing the tempo of the manual task (2:3 vs. 2:3-F) did result in a decreased postural time-to-contact in the two-footed posture. Coherence analysis revealed that the coupling between the postural and manual task significantly decreased as a function of postural difficulty (going from a two-footed to a one-footed posture) and rhythmic complexity (1:1 vs. 2:3). Taken together, these results demonstrate that expert marching percussionists systematically decouple postural and manual fluctuations in order to preserve the performance of the rhythmic movement task.     

Children with developmental coordination disorder (DCD) can adapt to perceptible and subliminal rhythm changes but are more variable

Children with DCD demonstrate impairments in bimanual finger tapping during self-paced tapping and tapping in synchrony to different frequencies. In this study, we investigated the ability of children with DCD to adapt motorically to perceptible or subliminal changes of the auditory stimuli without a change in frequency, and compared their performance to typically developing controls (TDC). Nineteen children with DCD between ages 6–11 years (mean age ± SD = 114 ± 21 months) and 17 TDC (mean age ± SD = 113 ± 21 months) participated in this study. Auditory perceptual threshold was established. Children initially tapped bimanually to an antiphase beat and then to either a perceptible change in rhythm or to gradual subliminal changes in rhythm. Children with DCD were able to perceive changes in rhythm similar to TDC. They were also able to adapt to both perceptible and subliminal changes in rhythms similar to their age- and gender- matched TDC. However, these children were significantly more variable compared with TDC in all phasing conditions. The results suggest that the performance impairments in bilateral tapping are not a result of poor conscious or sub-conscious perception of the auditory cue. The increased motor variability may be associated with cerebellar dysfunction but further behavioral and neurophysiological studies are needed.     

任务呈现方式、双任务反应顺序影响算术估算策略选择与执行

采用选择/无选范式,通过操纵任务呈现方式(估算题目的数字消失与否)与主次任务反应顺序(先反应算术任务或先反应字母任务),考察了双任务协调在算术策略选择与执行中的潜在作用。结果显示:(1)不同双任务呈现情境中个体的算术策略表现有明显区别。算术题目数字不消失相比消失时,个体对主、次任务的回答正确率都比较低,在策略选择上更倾向于选择较简单策略,在策略执行上准确性偏低;(2)双任务反应顺序会影响算术策略运用表现。先反应算术任务时,双任务情境只影响策略执行的准确性;而先反应字母任务时,双任务情境对策略执行的准确性和反应速度均发挥干扰作用,且估算题目的数字消失与否对策略选择准确性的影响更大,策略选择适应性之间的差异亦更加明显。上述发现对于深入理解双任务协调功能在策略运用中的作用机制具有重要意义。     

The dynamics of coordinated reaching and grasping: Scanning prehension properly

Prehension is the act of coordinated reaching and grasping. S.A. Wallace, E. Stevenson, A. Spear, D.L. Weeks [Hum. Movement Sci. 13 (1994) 255–289] proposed to assess the stability of this coordination by scanning the dynamics of prehension. The scanning method proposed by these authors prompted participants to position their peak hand aperture at different locations along the trajectory. Comparing the actual performance with the required performance, Wallace and colleagues concluded that there was a single stable pattern of coordination, albeit different for each individual. Here, we show that the method developed by Wallace et al. (1994, loc. cit.), and later used by C. Button, S. Bennett, K. Davids [Hum. Movement Sci. 17 (1998) 801–820] was flawed. We propose two potential fixes to the method and report a replication of the original experiment. Interpretation of the data with a corrected scanning technique showed that the method does not seem to be able to result in an unambiguous and precise assessment of the locus of stability.