The Effect of Different Combinations of Practice Schedules on Motor Response Stability during Practice.

Many results in motor learning have indicated that relative and absolute timing dimensions are modulated by factors that modify response stability among trials. One of these factors is the combination of constant and variable practices. Although many researchers have investigated the combination of practice schedules, these researchers have used measurements that do not assess performance and motor response separately. This study aimed to investigate the effect of different combinations of practice schedules on motor response stability during practice. Participants performed a sequential key-pressing task with two goals: (1) to learn the relative timing dimension and (2) the absolute timing dimension. Participants were assigned to one of two groups: constant-variable or variable-constant. Our findings indicate an influence of the increase in variability over the practice in the constant-variable group. Precisely, the increase in variability of total time in the second half (constant-variable group) of practice was followed by the maintenance of the same level of cross-correlate between absolute timing error and variability of total time. Finally, our findings support the hypothesis that practicing in a constant schedule favors the relative timing dimension of learning regardless of the order in which the constant practice is provided.

The effect of context variability on motor learning.

Although the practice schedule and variation in incidental context have been investigated together, it is not clear whether just variation in incidental context can beneficiate motor learning. Therefore, the present study aimed to investigate the effect of context variability on motor learning. We hypothesized the practice in a variable incidental context would enable learners to be more resistant to the effects of the contextual changes when compared to a constant incidental context practice. Twenty-four participants were assigned to one of the two groups: constant incidental context (G_CC) or variable incidental context (G_VC). During practice, the G_CC practiced a sequence keypressing task in one color and a position showed on the computer screen. The G_VC practiced the same sequence in four different combinations of color and position. Twenty four hours, the same contexts practiced on practice (SAME) was performed and immediately after, a new sequential movement in new color and new position (SWITCH) was performed. The results indicated that the G_VC showed better performance than the G_CC on the SWITCH condition, mainly in measures related to planning/selection process. The results were explained by degree of similarity among processing events engaged during different moments and by development of a filter of information based on attentional selection.

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

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.

The contextual interference effect in the learning of a manual aiming task / O efeito da interferência contextual na aprendizagem de uma tarefa de apontamento manual

ABSTRACT The association between contextual interference effect (CIE) and kinematic measures has been little investigated. The purpose of this study was to investigate the CIE on velocity and acceleration kinematic profiles of upper limb. Thirty-two subjects (23,7 ± 3,3 years) were assigned to groups of blocked practice (GPB) and random practice (GPA). The task consisted in achieve three targets in three specific sequences as quickly and accurately as possible. The study was designed in acquisition phase and transfer test. The variables of performance were reaction time, movement time, and response time and the kinematic variables were peak of speed, relative time to peak of speed, and number of peak acceleration points. The main findings showed that GPA showed lower movement time and response time than GPB. Regression analysis indicated that change in peak velocity during practice was associated to the change of the reaction time from practice to the transfer test. As peak velocity is a measure related to preprogramming, it is suggested that central control was essential to the CIE.

RESUMO Pouco se sabe a respeito da associação entre o efeito da interferência contextual (EIC) e medidas cinemáticas. O objetivo do presente estudo foi investigar o EIC nos perfis cinemáticos de velocidade e aceleração do membro superior. Vinte e dois participantes (23,7 ± 3,3 anos) foram alocados em dois grupos de prática: em blocos (GPB) e aleatória (GPA). A tarefa consistiu em acertar três alvos apresentados no monitor em três sequências pré-determinadas o mais rápido e preciso possível. O estudo foi dividido em fase de aquisição e teste de transferência. As variáveis de desempenho foram tempo de reação, tempo de movimento e tempo de resposta e as variáveis cinemáticas foram pico de velocidade, tempo relativo para o pico de velocidade e número de correções para alcançar o alvo. Os principais achados mostraram que o GPA apresentou menor tempo de movimento e de resposta do que o GPB. Análise de regressão indicou que a mudança observada ao longo da prática para a medida de pico de velocidade estava associada à mudança do tempo de reação da fase de aquisição para o teste de transferência. Como o pico de velocidade é uma medida associada à pré-programação, sugere-se que o controle central seja essencial para a observação do EIC.

Differences in motor control of an aiming task in different group ages of the elderly

This study aimed to investigate how different age groups of older adults perform and control movements in a goal-directed aiming task and the importance of visual feedback during these movements. Methods: Participants included 22 old adults, divided in two age groups: younger (60-70 yr) and older (80-90 yr). Subjects performed the task in a condition with vision and in a condition where vision was deprived. Results: In the vision condition, younger subjects showed smaller movement and reaction times, smaller radial errors, higher peak velocities, lower relative times to reach peak velocity than older subjects. In the vision-deprived condition the same results were found, except for radial error measure, where no significant effect for age groups was found. Conclusion: Younger subjects seemed to rely more on visual online feedback than older subjects and older subjects use other sensory sources to meet the possible deficits of information obtained by vision.(AU)

Task engagement and mental workload involved in variation and repetition of a motor skill.

Explanatory hypotheses proposed in behavioral studies assumed that less repetitive practice schedules, such as random practice, seem to demand greater cognitive effort than more repetitive types of practice organization, such as constant. All of these hypotheses emphasize the enhanced demand to memory processes promoted by less repetitive practice schedules. In the present study, we investigated the cognitive effort involved in random and constant practice schedules with an electrophysiological approach. Twenty-one male participants practiced a sequential key-pressing task with two goals: learning the relative timing dimension and learning the absolute timing dimension. Sixty trials were performed in a constant practice schedule (only one absolute timing goal), and sixty trials were performed in random order (three absolute timing goals). Two electroencephalography based measures of cognitive states were used: (a) task engagement (sensory processing and attention resources) and (b) mental workload (working memory load). The results showed that random practice induced greater cognitive effort than constant practice when task engagement was analyzed. Throughout practice, both task engagement and mental workload decreased more in the constant practice condition than in the random practice condition. The increased demand for sensory processing observed in random practice opens a new exciting field of study in practice organization.