动作记忆SPT优势效应的理论探讨

操作条件下的记忆效果好于语词条件下记忆效果的现象被称为动作记忆SPT效应。以往研究先后提出非策略加工、多通道加工、动作编码及情景整合理论来解释SPT效应,但这些理论解释仍存在矛盾和分歧,并阻碍了当前动作记忆领域的研究进展。为了解决目前的理论困境,本文详细地阐述了各理论的核心内容、发展历程及其存在矛盾和分歧的原因,并提出应以加工过程与加工对象相结合的视角来建立新的理论模型,以进一步促进实证研究的展开。     

Atypical speech lateralization in adults with developmental coordination disorder demonstrated using functional transcranial Doppler ultrasound

Research using clinical populations to explore the relationship between hemispheric speech lateralization and handedness has focused on individuals with speech and language disorders, such as dyslexia or specific language impairment (SLI). Such work reveals atypical patterns of cerebral lateralization and handedness in these groups compared to controls. There are few studies that examine this relationship in people with motor coordination impairments but without speech or reading deficits, which is a surprising omission given the prevalence of theories suggesting a common neural network underlying both functions. We use an emerging imaging technique in cognitive neuroscience; functional transcranial Doppler (fTCD) ultrasound, to assess whether individuals with developmental coordination disorder (DCD) display reduced left‐hemisphere lateralization for speech production compared to control participants. Twelve adult control participants and 12 adults with DCD, but no other developmental/cognitive impairments, performed a word‐generation task whilst undergoing fTCD imaging to establish a hemispheric lateralization index for speech production. All participants also completed an electronic peg‐moving task to determine hand skill. As predicted, the DCD group showed a significantly reduced left lateralization pattern for the speech production task compared to controls. Performance on the motor skill task showed a clear preference for the dominant hand across both groups; however, the DCD group mean movement times were significantly higher for the non‐dominant hand. This is the first study of its kind to assess hand skill and speech lateralization in DCD. The results reveal a reduced leftwards asymmetry for speech and a slower motor performance. This fits alongside previous work showing atypical cerebral lateralization in DCD for other cognitive processes (e.g., executive function and short‐term memory) and thus speaks to debates on theories of the links between motor control and language production.     

Time for action versus action in time: time estimation differs between motor preparation and execution

Theories relating to time perception and motor performance predict very different temporal distortions depending on the synchronisation or succession of temporal processing and motor behaviour. However, our knowledge about the temporal difference between motor preparation and execution is still scarce. In order to expand on prior studies, two different time reproduction tasks were utilised to measure motor preparation and motor execution. We found that motor preparation of a planned action allows participants to complete the time reproduction task more accurately and, in short duration trials, less variably than for motor execution. Furthermore, under-reproduction was found in motor preparation compared to motor execution, which may be caused by increased temporal information processing. According to the attentional gate theory, more attention allocated to time processing and reduced motor distraction leads to less temporal distortion in the motor preparation. The findings are also important for designing to study consciousness, temporal and visual processing.     

Changing Their Minds: Enhancing Poststroke Occupational Performance Using Transcranial Direct Current Stimulation

Stroke remains a leading cause of disability, with survivors experiencing long-term decrements in independence and quality of life. Occupational therapists (OTs) employ numerous neurorehabilitative treatment approaches to remediate impairments that are impeding performance. OTs also use physical agent modalities to facilitate increased participation and success in therapy. One such modality is transcranial direct current stimulation (tDCS), a form a noninvasive brain stimulation that can be overlaid onto task practice and delivers a constant, low intensity current into the brain. tDCS is safe, portable, and efficacious in remediating a variety of deficits, yet is not consistently incorporated into clinical practice. The authors discuss the mechanisms, safety, evidence, and potential applications of tDCS to enhance outcomes for this growing population.     

Reductive and Emergent Views on Motor Learning in Rehabilitation Practice

To allow different views on motor learning to inform rehabilitation research, the authors aimed to explicate a frequently missed yet fundamental difference in starting point of such views. By considering how rehabilitation in practice answers the question of what parts an activity consists of, reductive and emergent approaches to motor learning are identified and traced throughout rehabilitation practice. The authors show that when a task is cut up along reductive dimensions while also apparently relying on emergent components, this unequally favors the reductive approach and acts to limit the views on motor learning available. By showing the approaches in practice, the authors hope to inspire an awareness that brings both approaches the opportunity to independently inform research so that new theories and practices can proliferate.     

The Effects of Sensory Manipulations on Motor Behavior: From Basic Science to Clinical Rehabilitation

Modifying sensory aspects of the learning environment can influence motor behavior. Although the effects of sensory manipulations on motor behavior have been widely studied, there still remains a great deal of variability across the field in terms of how sensory information has been manipulated or applied. Here, the authors briefly review and integrate the literature from each sensory modality to gain a better understanding of how sensory manipulations can best be used to enhance motor behavior. Then, they discuss 2 emerging themes from this literature that are important for translating sensory manipulation research into effective interventions. Finally, the authors provide future research directions that may lead to enhanced efficacy of sensory manipulations for motor learning and rehabilitation.     

Grasp-Based Functional Coupling Between Reach- and Grasp-Related Components of Forelimb Muscle Activity

How are appropriate combinations of forelimb muscles selected during reach-to-grasp movements in the presence of neuromotor redundancy and important task-related constraints? The authors tested whether grasp type or target location preferentially influence the selection and synergistic coupling between forelimb muscles during reach-to-grasp movements. Factor analysis applied to 14–20 forelimb electromyograms recorded from monkeys performing reach-to-grasp tasks revealed 4–6 muscle components that showed transport/preshape- or grasp-related features. Weighting coefficients of transport/preshape-related components demonstrated strongest similarities for reaches that shared the same grasp type rather than the same target location. Scaling coefficients of transport/preshape- and grasp-related components showed invariant temporal coupling. Thus, grasp type influenced strongly both transport/preshape- and grasp-related muscle components, giving rise to grasp-based functional coupling between forelimb muscles.     

OPTIMAL practice conditions enhance the benefits of gradually increasing error opportunities on retention of a stepping sequence task

IntroductionPhysical therapists should implement practice conditions that promote motor skill learning after neurological injury. Errorful and errorless practice conditions are effective for different populations and tasks. Errorful learning provides opportunities for learners to make task-relevant choices. Enhancing learner autonomy through choice opportunities is a key component of the Optimizing Performance through Intrinsic Motivation and Attention for Learning (OPTIMAL) theory of motor learning. The objective of this study was to evaluate the interaction between error opportunity frequency and OPTIMAL (autonomy-supportive) practice conditions during stepping sequence acquisition in a virtual environment.MethodsForty healthy young adults were randomized to autonomy-supportive or autonomy-controlling practice conditions, which differed in instructional language, focus of attention (external vs internal) and positive versus negative nature of verbal and visual feedback. All participants practiced 40 trials of 4, six-step stepping sequences in a random order. Each of the 4 sequences offered different amounts of choice opportunities about the next step via visual cue presentation (4 choices; 1 choice; gradually increasing [1-2-3-4] choices, and gradually decreasing [4-3-2-1] choices). Motivation and engagement were measured by the Intrinsic Motivation Inventory (IMI) and the User Engagement Scale (UES). Participants returned 1–3 days later for retention tests, where learning was measured by time to complete each sequence. No choice cues were offered on retention.ResultsParticipants in the autonomy-supportive group outperformed the autonomy-controlling group at retention on all sequences (mean difference 2.88s, p < .005, t[6835] = 3.42). Participants in both groups had the most difficulty acquiring the decreasing choice (4-3-2-1) sequence (p < .001, t[6835] = −4.26) and performed most poorly on the errorful (4 choice) sequence (p < .034, t[6835] = 2.65) at retention. Participants in the autonomy-supportive group performed best at retention on the increasing choice (1-2-3-4) sequence (p < .033, t[6835] = −2.7). Participants in both groups who reported greater attention to the task on the UES Average Focused Attention subscale during acquisition had poorer retention performance, particularly for the decreasing choice (4-3-2-1) sequence (p < .005, t(6835) = 3.39). Participants in the autonomy-supportive group reported significantly higher overall motivation (p = .007, t(38) = 0.728, d = 0.248) on the IMI as compared to the autonomy-controlling group.ConclusionIndividual benefits of errorless learning and autonomy-supportive practice conditions, with an interaction effect for practice that begins errorless but adds increasing error opportunities over time, suggest that participants relied on implicit learning strategies for this full body task and that feedback about successes minimized errors and reduced their potential information-processing benefits. Subsequent work will continue to examine how assigning a positive versus a negative quality to error provision influences the benefits of errorful learning in a variety of tasks.     

Association between fine motor skills and binocular visual function in children with reading difficulties

Performance of fine motor skills (FMS) assessed by a clinical test battery has been associated with reading achievement in school-age children. However, the nature of this association remains to be established. The aim of this study was to assess FMS in children with reading difficulties using two experimental tasks, and to determine if performance is associated with reduced binocular function. We hypothesized that in comparison to an age- and sex-matched control group, children identified with reading difficulties will perform worse only on a motor task that has been shown to rely on binocular input. To test this hypothesis, motor performance was assessed using two tasks: bead-threading and peg-board in 19 children who were reading below expected grade and age-level. Binocular vision assessment included tests for stereoacuity, fusional vergence, amplitude of accommodation, and accommodative facility. In comparison to the control group, children with reading difficulties performed significantly worse on the bead-threading task. In contrast, performance on the peg-board task was similar in both groups. Accommodative facility was the only measure of binocular function significantly associated with motor performance. Findings from our exploratory study suggest that normal binocular vision may provide an important sensory input for the optimal development of FMS and reading. Given the small sample size tested in the current study, further investigation to assess the contribution of binocular vision to the development and performance of FMS and reading is warranted.