TDCS of the Primary Motor Cortex: Learning the Absolute Dimension of a Complex Motor Task.

The primary motor cortex (M1) is one of the main cortical areas involved in motor learning. However, little is known about its differential role in the learning of the relative and absolute dimensions of motor skills. We investigated the role of M1 in the learning of the dimensions of a complex motor skill. Forty-eight participants practiced golf putting and were stimulated for 20 minutes with real or sham bihemispheric tDCS before acquisition. tDCS improved global performance from pre- to post-test. Only those with worse initial performance who were stimulated by tDCS showed a significant improvement in the skill's absolute dimension. No effects of tDCS were found for the relative dimension. Our results suggest that M1 has a distinct participation in the learning of the absolute dimension of complex motor skills, and tDCS effects are influenced by the learner's level of initial performance.

Does exercise-induced muscle damage impair subsequent motor skill learning?

Motor skill learning is a fundamental aspect of human behavior based on the calibration of internal models via sensory information such as proprioception. Some conditions, as exercise-induced muscle damage (EIMD), disrupt proprioceptive information, and may cause learning impairment. Such possible relation between EIMD and motor skill learning has not yet been investigated and it is the aim of this study. For this purpose, thirty male university students (19.3 ±â€¯1.8 years) were equally assigned to two groups: EIMD and CON group. The EIMD group received a treatment to induce muscle damage consisting of a weight lifting protocol directed to the agonist muscles related to the task prior to the pretest and to the learning sessions. EIMD was verified and compared between groups and along the process (0-168 h) by means of the degree of delayed onset muscle soreness (DOMS), perceived total quality recovery and maximal isometric strength (MIS). To investigate motor skill learning, both groups practiced a dart throwing task for four sessions with 150 trials in each session. Recovery status and DOMS were recovered at 96 h in the EIMD group, and MIS was not recovered throughout 168 h. In contrast, muscle damage parameters were not altered across 168 h in the CON group. Accuracy and consistency were compared within and between groups in a pretest posttest design. The EIMD group showed less accurate and consistent results on the long term (delayed posttest). Results confirmed our hypothesis that EIMD, a common condition in sports and in rehab practices, may hinder motor skill learning, possibly due to neurological aspects such as proprioceptive information, its relation to central nervous system reorganization and internal model consolidation.

Extensive practice improves adaptation to unpredictable perturbations in a sequential coincident timing task.

Extensive practice is associated with a higher level of learning than practice until performance stabilization. This is partially attributable to the changes in the variability of the structure that control the motor skill that occur during practice. However, because both conditions result in performance stabilization, the error in the task performance does not decrease further, and it is necessary to introduce higher demands (e.g., unpredictable perturbations) into the task for differences between the two conditions to arise. This study aimed to investigate whether extensive practice contributes to adaptation to unpredictable perturbations in a sequential motor skill task as compared to practice until performance stabilization. Thirty-four self-reported right handed young adults performed a sequential coincident timing task and were assigned to two groups during the first phase of experiment: the stabilization group (SG) or the extensive practice group (EG), which differs with respect to the quantity of practice. In the second phase, both groups performed under equal conditions and the subjects practiced the same task performed in the first phase, but unpredictable changes in the velocity of the visual stimulus were occasionally introduced. The results suggest that extensive practice improves adaptation to unpredictable perturbations better than practice until performance stabilization and indicates that the motor learning process continues after performance stabilization.

Efeitos de faixas de amplitude de CP na aprendizagem do saque tipo tênis do voleibol / Effects of the bandwidth KP on the learning of the volleyball tennis serve

Este estudo teve como objetivo investigar os efeitos de duas faixas de amplitude de Conhecimento de Performance (CP) na aprendizagem do saque tipo tênis do voleibol. Essa questão foi testada com uma faixa de amplitude estreita e uma ampla e mais um grupo controle. O estudo foi composto por um pré-teste, fase de aquisição e teste de retenção. Foram analisadas medidas de desempenho e dos componentes do padrão da habilidade. Apesar dos grupos mostrarem desempenho semelhante no teste de retenção, a faixa ampla foi a única que levou a melhora do desempenho. Além disso, a faixa ampla conduziu a mais mudanças no padrão da habilidade do que a faixa estreita ou o grupo controle.

This study aimed to investigate two bandwidth Knowledge of Performance (KP) effects on the learning of the volleyball tennis serve. This question was tested with a thin and wide bandwidth KP plus a control group. The study was composed by a pre test, acquisition phase and retention test. It was analyzed performance and components of the motor pattern measures. Although the groups showed similar performance on retention test, only wide bandwidth conducted to a better performance. Although all groups showed similar performance during retention test only the wide bandwidth conducted to performance improvement. Moreover, the wide bandwidth conducted to more changes in movement pattern than thin bandwidth or control group.