Asymmetric effector transfer of complex movement sequences

The simultaneous changes in motor performance and EEG patterns in beta band during learning dart throwing skill in dominant and non-dominant hand

Background: Although changes in performance during the learning of various sports skills have been studied, however, how these changes at the brain level is still unknown. The aim of this study was to investigate simultaneous changes in motor performance and EEG patterns in beta band during learning dart throwing skill in dominant and non-dominant hand. Methodology: The samples consisted of 14 non-athlete students with an average age of 23 ± 2.5, which were divided into two group dominant hand (7) and non-dominant hand (7). Repeated measures ANOVA were used to measure data at the execution level and changes in EEG activity. Results: The results of this study at the performance level showed a significant reduction in the absolute error of dart throwing and at the same time at the brain level increased EEG activity in frontal and parietal-posterior regions along with decreased central area activity in acquisition and retention stages in both groups (P<.05). Also, there was a significant difference between the activity of EEG pattern in the dominant and non-dominant hand groups except for two channels AF3 and PO4 (P<.05). Conclusion: In general, the results of this study showed that along with relatively constant changes in performance during dart skill learning, relatively constant changes in EEG activity pattern occur, so that the concept of motor learning is also visible at the brain level. Also, the results of this study supported the existence of the different motor program for dominant and non-dominant hand control in the conditions of bilateral transfer control.

Sleep-related offline learning in a complex arm movement sequence

Sleep is known to elicit off-line improvements of newly learned procedural skills, a phenomenon attributed to enhancement consolidation of an internal skill representation. In the motor domain, enhancement consolidation has been reported almost exclusively for sequential-finger-tapping skills. The aim of the present study was to extend the notion of sleep-related enhancement consolidation to tasks closer to everyday motor skills. This was achieved by employing a sequence of unrestrained reaching-movements with the non-dominant arm. Fifteen reaching-movements had to be executed as fast as possible, following a spatial pattern in the horizontal plane. Terminating each movement, a peg had to be fitted into a hole on an electronic pegboard. Two experimental groups received initial training, one in the evening, the other one in the morning. Subsequently, performance in both groups was retested twelve, and again 24 hrs later. Thus, during retention each individual experienced a night of sleep, either followed or preceded by a wake interval. Performance error remained low throughout training and retests. Yet mean total execution time, indicative of task execution-speed, significantly decreased for all individuals throughout initial training (no group differences), and significantly decreased again in either group following nocturnal sleep, but not following wake. This finding does not appear to result merely from additional practice afforded at the time of retests, because only after a night of sleep individuals of both experimental groups also revealed performance improvement beyond that estimated from their initial training performance.

Age-related effects in interlimb practice on coding complex movement sequences

Hikosaka et al. (1999) proposed that sequential movements are acquired in independent visual-spatial and motor coordinate systems with coding initially represented in visual-spatial coordinates, and later after extended practice in motor coordinates. One aspect of sequence learning that has not been systematically studied, however, is the question of whether or not older adults show the same pattern of coding in inter-limb practice as younger learners. In the present experiment an inter-limb practice paradigm was designed to determine the role that visual-spatial (Cartesian) and motor (joint angles, activation patterns) coordinates play in the coding and learning of a complex movement sequence. Younger and older adults practiced a 16-element movement sequence with one limb on Day 1 and the contra-lateral limb on Day 2. Practice involved the same sequence with either the same visual-spatial or motor coordinates on the two days. Retention tests were conducted on Day 3. Results indicated that keeping the visual-spatial coordinates the same during acquisition resulted in superior retention only for younger adults. Results also indicated the overall slowing of sequential movement production for older adults which appears to result from these participants inability to impose a structure on the sequence. This provides strong evidence that the visual-spatial code plays a dominant role in complex movement sequences and this code is represented in an effector-independent manner for younger adults, but not for older adults.

Intermanueller Transfer und Händigkeit

Zusammenfassung. In dem Experiment wurde der intermanuelle Transfer auf eine neue dynamische Anforderung und Händigkeit untersucht. Gegenstand ist das Lernen einer Bewegungssequenz. Die Aufgabe der Lerner bestand in dem Erwerb einer 16-Elementigen Bewegungssequenz. Nach einem anfänglichen Training einer Bewegungssequenz für Rechts- und Linkshänder in Abhängigkeit der Starthand (dominante, nicht-dominante Hand) wurden nach einem Intervall von 24 Stunden ein Behaltenstest und zwei Transfertests appliziert. In dem Behaltenstest musste die gelernte Sequenz mit der trainierten Hand ohne Zusatzlast (0 kg) reproduziert werden. In den beiden ausbalancierten Transfertests sollte sowohl mit der trainierten als auch mit der untrainierten kontralateralen Hand eine zusätzliche Masse von 1 kg bewegt werden. Die Ergebnisse zeigen, dass sowohl Rechts- als auch Linkshänder auf unterschiedliche dynamische Eigenschaften mit ihrer dominanten Hand transferieren können. Rechtshänder können sowohl mit der rechten als auch der linken Hand unabhängig von ihrer Starthand auf neue dynamische Anforderungen transferieren (Symmetrie). Eine Asymmetrie in dem Übertrag zeigt sich bei den Linkshändern, die unabhängig von ihrer trainierten Hand nicht auf ihre rechte Hand und auf eine veränderte dynamische Anforderung transferieren können.