Differences in the mechanisms of the single movements of the right and left hands and of the sequences of these movements are connected with the localization of the brain area, which provide sequence movement control by both hands in the left premotor cortex. What are the features of mechanisms of learning sequences of hand movements?
This paper presents a comparative analysis of three series of experiments in which subjects repeatedly represented memorized sequence of movements of their right or left hand through six random positions on 2D plane. In all series right-handed volunteers performed the task first with one hand (right or left, the groups R or L, respectively) and continued by the opposite one. The number of repeated sequences of each hand was 36 and 30 in the first two series and 3 - in the third.
The results showed that the previous long work by the right hand (series 1 and 2, group R) leads to more accurate reproduction of the movements by continued left hand (as compared with the right hand and with the left hand in the group L). The previous short work by the right hand (Series 3, group R), on the contrary decreases the accuracy of the continued left hand. Therefore, left hand works better when it works after a large number of repetitions by the right hand (series 1 and 2), while the accuracy of the left hand after the right one worse at initial stages of training (with a small number of repetitions, series 3).
Data suggests that the way to encode information about the sequence, activated by the right hand, in the initial stages of training prevents subsequent task performance by the left hand, but after long-term training it has been successfully used. The differences are supposed to be connected with the increasing of possibility to use left-hemispheric mechanisms by the left hand as the consolidation of skill of sequence acquisition increases.