效应器在动作序列学习中的作用机制探析

动作序列学习是动作技能学习的重要组成部分,其中大部分动作序列学习都有效应器参与。目前有关效应器在动作序列学习中的作用机制存在两种观点：一是依存于效应器的观点,即动作序列技能的获得依附于具体的效应器,不可向其他效应器迁移,其学习的本质是建立反应或肌肉间的联结。二是独立于效应器的观点,即动作序列技能的获得并不依存于具体效应器,某个效应器获得的技能可以向其他效应器迁移,其学习的本质是建立抽象的刺激表征联结。效应器作用机制随练习程度、意识状态及其他条件的不同而有所变化。     

Transfer of Work Decrement in Motor Learning

Two experiments tested the hypothesis that the decremental effects of massed practice are due to the development of a negative drive (Hull’s I_r). The results indicated that the decremental effects of massed practice on either the pursuit rotor or the two-hand coordinator do not transfer to depress performance or reminiscence on the other task. The results did not support Hull’s drive interpretation but were explained by theories attributing decrement to a decreased level of arousal.     

Individualized Challenge Point Practice as a Method to Aid Motor Sequence Learning

We conducted two studies to investigate if and how: (1) the rate of skill acquisition was related to motor performance at retention of a serial RT task (Study 1); and (2) whether rate of skill acquisition and baseline performance could be used to design schedules of practice related to contextual interference (CI) to enhance motor learning (Study 2). In Study 1, a slower rate of skill acquisition of repeating sequences in practice was related to faster response times at retention. Based on performance in Study 1, three levels of individualized CI were created for Study 2. Compared to low and moderate levels of CI, the higher CI practice condition led to faster response times in retention. We conclude that an individualized ‘challenge point’, which generates high CI enhances motor learning by optimizing challenge.     

Conscious Control Is Associated With Freezing of Mechanical Degrees of Freedom During Motor Learning

This study investigated whether conscious control is associated with freezing of mechanical degrees of freedom during motor learning. Participants practiced a throwing task using either error-strewn or error-reduced practice protocols, which encourage high or low levels of conscious control, respectively. After 24 hr, participants engaged in a series of delayed retention and transfer tests. Furthermore, propensity for conscious control was assessed using participants' ratings and freezing was gauged through movement variability of the throwing arm. Performance was defined by mean radial error. In the error-strewn group, propensity for conscious control was positively associated with both freezing and performance. In the error-reduced group, propensity for conscious control was negatively associated with performance, but not with freezing. These results suggest that conscious control is associated with freezing of mechanical degrees of freedom during motor learning.     

Imaging brain plasticity during motor skill learning

The search for the neural substrates mediating the incremental acquisition of skilled motor behaviors has been the focus of a large body of animal and human studies in the past decade. Much less is known, however, with regard to the dynamic neural changes that occur in the motor system during the different phases of learning. In this paper, we review recent findings, mainly from our own work using fMRI, which suggest that: (i) the learning of sequential finger movements produces a slowly evolving reorganization within primary motor cortex (M1) over the course of weeks and (ii) this change in M1 follows more dynamic, rapid changes in the cerebellum, striatum, and other motor-related cortical areas over the course of days. We also briefly review neurophysiological and psychophysical evidence for the consolidation of motor skills, and we propose a working hypothesis of its underlying neural substrate in motor sequence learning.     

不同运动经历人群的内隐序列学习能力

考察不同运动经历人群的内隐序列学习能力。被试为上海体育学院小球运动员和非运动员;实验结合PDP,采用序列学习任务,并测试操作智商与记忆广度。结果发现,运动员在15个组段上的平均反应时、内隐学习量、自动提取贡献率上显著大于非运动员;不同水平运动员在内隐学习量上差异显著。研究结论:运动员的内隐序列学习能力显著好于非运动员,与运动水平有关,与智商无显著相关;这种内隐序列学习能力可能是某种运动能力的表现形式。     

Molecular Mechanisms Associated with the Benefits of Variable Practice in Motor Learning

Abstract

Variable practice promotes a higher level of motor learning than constant practice. The glutamate receptors, n-methyl-d-aspartate (NMDA) and alfa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA), have been associated with the changes in motor cortex that occur throughout the process of motor learning. Considering that, it is possible that variable practice is more associated with the NMDA and AMPA receptors than constant practice. This study aimed ao investigating the association between the glutamate receptors, NMDA and AMPA, and constant and variable practice schedules. Seventy-eight male mice practiced the rotarod task in a constant or variable scheduling, in two consecutive days (acquisition phase). Learning tests were performed 24?h and 10?days after the end of the acquisition phase. Variable practice was more associated with the NMDA receptor and had a greater AMPA receptor expression than constant practice. The results suggest that the benefits of variable practice are result of both the greater dependency on the NMDA receptor and the greater AMPA receptor expression.     

Motor Learning through Induced Variability at the Task Goal and Execution Redundancy Levels

The authors examined the influence of introducing variability at two different levels in the learning of a striking task. Variability at the task goal level was introduced by changing target location, whereas variability at the execution redundancy level was introduced by using an intermediate target that constrained participants to use different paths from trial to trial to strike the same target. After practice, participants were transferred to 2 test conditions: (a) a fixed-target test, where the position of the target was unchanged; and (b) a variable-target test, where the position of the target was varied from trial to trial. The results from the manipulation at the task goal level were consistent with predictions from the specificity of practice hypothesis. In both the fixed- and variable-target tests, the best performance was achieved by the group that had practiced in the condition matching the test condition. At the execution-redundancy level, practicing multiple solutions to achieve the task goal did not improve performance in either the fixed- or variable-target tests. These results show that introducing variability at the task goal and execution redundancy levels has different effects on learning and generalization and that practice schedules that constrain the participant to use redundant solutions may not facilitate learning.     

Performance and Learning of Generalized Motor Programs: Relative (GMP) and Absolute (Parameter) Errors

The effects of practice (Experiment 1) and parameter variability (Experiment 2) on the learning of generalized motor programs (GMPs) and movement parameterization were investigated In each experiment, 2 tasks with different relative force-time structures were tested. Participants (N = 32, Experiment (N = 40, Experiment 2) attempted to exert a pattern of force that resembled in force and time a waveform that was displayed on a computer monitor. In both experiments, the analysis suggested that the GMP, although refined over practice, was relatively stable (i.e., resistant to decay and interference), even early in practice (after 20 trials). In addition, the results indicated that constant and variable parameter practice did not differentially affect GMP learning but did degrade the learning of the parameter that was not varied. The data provided additional evidence for the dissociation of the GMP and the parameterization processes proposed in GMP theory. Contrary to schema theory, the present data suggest an interdependence between the force and the time parameters: The manipulation of 1 of the parameters has a negative effect on the learning of the other parameter.