O papel da área motora suplementar na aprendizagem das dimensões relativa e absoluta de uma habilidade motora

Abstract

The motor learning can be investigated at different levels of analysis, such as thebehavioral and neurobiological level. On a behavioral level, learning a motor skill hastwo dimensions, the absolute and the relative. The absolute dimension is representedby the total time, total force and amplitude. The relative dimension is represented bythe relative time, relative strength and sequencing. At the neurobiological level ofanalysis, one of the issues investigated is the involvement of brain areas in control andlearning of motor skills. The concepts used between the two levels of analysis appearto be overlapped. Behavioral studies have not investigated the associations betweenthe absolute and relative dimensions and brain areas. Neurobiological studies, incontrast, have not used tasks in which the dimensions could be analyzed separately.Therefore, the aim of this study was to evaluate the role of the supplementary motorarea in learning the absolute and relative dimensions of a motor skill. To this end, 40participants were randomly divided in two groups, in a way that one group hadtranscranial direct-current stimulation (tDCS) on the AMS (G-AMS) and the other wasthe placebo group (G-P). After the stimulation period, the two groups performed amotor task which consisted of pressing keys on a alphanumeric keyboard with only theindex finger of the right hand, following the sequency of (2-8-6-4) respectively. Theexecution of the task was separated in acquisition phase, retention test and transfertest. In the acquisition phase participants performed 120 trials in a total time of 900 msand a relative time of 22.2% between keys (2 to 8), 44.4% (6 of 8) and 33.3% (4 to 6)and with feedback of the total time and the relative percentual after each trial. In theretention test participants performed 12 trials in the same conditions of the acquisitionphase, but without feedback. In the transfer test, participants performed 12 trials withthe same relative time on the acquisition phase, but with a total time of 1300 ms andno feedback. The results showed no significant difference between the groups in anyof the measures related to the relative dimension. In absolute dimension, it was founda lower level of off-line learning for the G-AMS from the end of the aquisition phase tothe retention test. On the other hand, it was found a higher level of off-line learning forthe G-AMS from the last block of the acquisition to the transfer test. In addition, the GAMSshowed better performance in the transfer test. Based on the results, stimulationof AMS did not interfere with the learning of the relative dimension. Conversely,stimulation of AMS showed different interferences in absolute dimension. Inconclusion, it is possible to infer that the AMS has an important role not only in learningthe relative dimension, but also in the absolute one