Journal of Motor Behavior最新文献

Parkinson's disease (PD) is associated with reduced coordination abilities. These can result either in random or rigid patterns of movement. The latter, described here as coordination rigidity (CR), have been studied less often. We explored whether CR was present in gait, quiet stance, and speech-tasks involving coordination among multiple joints and muscles. Kinematic and voice recordings were used to compute measures describing the dynamics of systems with multiple degrees of freedom and nonlinear interactions. After clinical evaluation, patients with moderate stage PD were compared against matched healthy participants. In the PD group, gait dynamics was associated with decreased dynamic divergence-lower instability-in the vertical axis. Postural fluctuations were associated with increased regularity in the anterior-posterior axis, and voice dynamics with increased predictability, all consistent with CR. The clinical relevance of CR was confirmed by showing that some of those features contribute to disease classification with supervised machine learning (82/81/85% accuracy/sensitivity/specificity).

There is debate about how implicit and explicit processes interact in sensorimotor adaptation, implicating how error signals drive learning. Target error information is thought to primarily influence explicit processes, therefore manipulations to the veracity of this information should impact adaptation but not implicit recalibration (i.e. after-effects). Thirty participants across three groups initially adapted to rotated cursor feedback. Then we manipulated numeric target error through knowledge of results (KR) feedback, where groups practised with correct or incorrect (+/-15°) numeric KR. Participants adapted to erroneous KR, but only the KR + 15 group showed augmented implicit recalibration, evidenced by larger after-effects than before KR exposure. In the presence of sensory prediction errors, target errors modulated after-effects, suggesting an interaction between implicit and explicit processes.

The objective of the experiment was to assess the change in attentional demands of a movement sequence guided by visual-spatial and motor representations across practice sessions in a dual-task probe paradigm. Participants were randomly assigned to either a 1-day or 2-day practice group. Following acquisition of the motor sequence task, participants first conducted a retention test and then four inter-manual transfer tests under single and dual-task conditions. The probe task was a simple reaction time. The inter-manual transfer tests, consisting of a mirror and non-mirror test, examined the development of the motor and visual-spatial representation, respectively. The results indicated that both representations guided the movement sequence and required attention. The attentional demands did not change with additional practice.

Main goal of this study was to investigate the influence of mental rotation tasks on postural stability. 84 participants were tested with two object-based mental rotation tasks (cube vs. human figures), an egocentric mental rotation task with one human figure, a math- (cognitive control) and a neutral task, while standing on a force plate in a both-legged narrow stance. Parameters related to the Center of Pressure course over time were used to quantify postural stability. The simultaneous solution of mental rotation tasks has led to postural stabilisation compared to the neutral condition. Egocentric tasks provoked more postural stability than object-based tasks with cube figures. Furthermore, a more stable stance was observed for embodied stimuli than for cube figures. An explorative approach showed the tendency that higher rotation angles of the object-based mental rotation task stimuli lead to more postural sway. These results contribute to a better understanding of the interaction between mental rotation and motor skills and emphasize the role of type of task and embodiment in dual task research.

This study explored the effect of dual task (DT) training compared to single task (ST) training on postural and cognitive performances in DT conditions in individuals with intellectual disability (ID). Postural sways and cognitive performances were measured separately and simultaneously before and after 8 weeks in the ST training group (STTG), the DT training group (DTTG) and the control group (CG) that did not received any training. Before training, postural sways and cognitive performances were higher in the DT condition compared to ST one in all groups. After training, postural sways were higher in the DT condition compared to the ST only in the STTG and the CG. The cognitive performance increased after training only in the DTTG.

Voluntary sway is the periodic movement of one's body back and forth. The study aimed to clarify the effects of sway frequency on center of pressure and joint angle during voluntary sway. We measured 10 unrestricted voluntary sway conditions with different frequencies and natural pace conditions. The frequencies ranged from 0.1 to 1 Hz in 0.1-Hz increments. The joint angles and centers of pressure during voluntary sway were compared between the conditions. The joint angle amplitude of the trunk and knee were greater in the slow frequency condition than in the fast frequency condition. The trunk and knee joint angles during voluntary sway were considered to change according to the sway frequency.

The objective of the present study was to examine the effects of gender stereotype on the performance and learning of a classical ballet pirouette in 11-year-old boys. Participants in the stereotype threat (ST) group were informed that, in general, boys tend to show worse results when completing the pirouette task in comparison to girls. Participants in the stereotype lift (SL) group were told that girls tend to show worse results in comparison to boys. The control group did not receive stereotype instructions. The results demonstrated worse performance during practice and retention (next day) for the ST group relative to the SL and control groups; the SL and control groups did not differ. The findings indicate that gender stereotype threat can undermine motor performance and learning in boys.

Traumatic brain injuries can result in short-lived and long-lasting neurological impairment. Identifying the correct recovery timeframe is challenging, as balance-based metrics may be negatively impacted if testing is performed soon after exercise. Thirty-two healthy controls and seventeen concussed individuals performed a series of balance challenges, including virtual reality optical flow perturbation. The control group completed a backpacking protocol to induce moderate fatigue. Concussed participants had lower spectral power in the motor cortex and central sulcus when compared to fatigued controls. Moreover, concussed participants experienced a decrease in overall theta band spectral power while fatigued controls showed an increase in theta band spectral power. This neural signature may be useful to distinguish between concussed and non-concussed fatigued participants in future assessments.