| 摘要: | 動作學習是一個透過反覆訓練，促進動作產生長期改變的歷程。其涵蓋三個主要範疇:序列學習、感知運動適應，以及動作敏銳性。相較於前兩者，專注於動作準確度與精準度的動作敏銳性研究相對較少。
動作轉移是動作學習中的另一個關鍵概念，指訓練後的動作表現是否能從受訓練側轉移至未受訓練的那一側。近期研究指出，大腦半球負責不同種類型的動作，對動作轉移具影響力。其中左半腦主要負責整體動態控制，右半腦則與動作的準確度與精準性有關。
感覺運動皮質的Beta波在動作準備與執行歷程中扮演關鍵角色。Beta波振幅在動作執行前會下降，在動作後則會上升，此現象反映出維持當前狀態的神經機制。除了振幅外，相位與跨頻譜耦合等頻譜特徵也參與動作調控。
本研究設計了自步學習的非慣用手飛鏢投擲訓練，探討訓練過程中是否能提高投擲的準確度，以及在這訓練過程中Beta波的變化。同時，考量大腦半球負責不同的運動型態，進一步來檢驗訓練非慣用手的精準度是否會轉移到慣用手。
行為結果顯示，訓練第一天的投擲精準度顯著高於訓練前，此進步主要是來自於低精準度組別的進步。檢驗投擲品質時，最佳投擲表現亦顯示第一天訓練後明顯提升，之後則沒有改變。腦電波的結果顯示，在動作執行完後，訓練的第一天的Beta波振幅的下降速率較訓練前來得快，但此變化與精準度的提升無直接的關聯。進一步的分析發現，精準度的提升與同側頂葉皮質至對側初級運動皮質間的Theta-Beta耦合呈正相關。然而，雖然非慣用手在訓練下有立即的進步，但此效果並未有效轉移至慣用手上。
本研究結合大腦半球的動作功能差異進行訓練設計，並在過去探討Beta波與動作敏銳性的研究基礎上，提出新的研究貢獻。結果指出，動作表現需仰賴大腦皮質間的互相合作，而非單一區域的活動，對未來探討動作敏銳性之神經機制具有參考價值。
;Motor learning is a complex process through which practice and experience lead to the permanent changes in movement skill capabilities. This field includes three main paradigms: sequence learning, sensorimotor adaptation, and motor acuity. However, motor acuity, which focuses on movement accuracy and precision, has been underexplored.
Bilateral transfer is another key concept in motor learning, referring to performance gains in an untrained limb resulting from training of the opposite limb. Recent evidences suggest that the extent of movement transfer is influenced by hemispheric specialization, the left hemisphere is more involved in trajectory dynamics, while the right hemisphere is more engaged in accuracy and precision.
Beta oscillations in the sensorimotor cortex play a critical role in movement preparation and execution. Typically, beta power decreases before movement and rebounds afterward, reflecting a neural mechanism for maintaining the status quo. In addition to power, spectral features such as phase and cross-frequency coupling also contribute to movement performance.
This study designed self-paced dart-throwing training to investigate how training enhances throwing precision and whether neural oscillations, particularly beta activity, reflect these changes. A secondary aim was to examine whether improvements from non-dominant hand training would transfer to the dominant hand.
Behavioral results showed significant improvements on the first day of training compared to the pre-training day, particularly in the low-precision group. When examining the throwing quality, the optimal throws improved significantly on the first training day but plateaued in the following days. EEG results revealed a faster beta power decrease rate after movement onset on the first training day; however, this reduction did not directly correlate with improved precision. Further analysis showed that the improved throwing precision was associated with stronger inter-areal theta-beta phase amplitude coupling from the ipsilateral parietal cortex to the contralateral primary motor cortex following movement onset.
Despite performance gains in the non-dominant hand, no improvement was observed in the dominant hand, indicating limited bilateral transfer.
The present study incorporates hemispheric specialization into the training paradigm, providing further insights into beta oscillations and extending previous findings on motor acuity. Furthermore, the results suggest that motor performance relies on network-level interaction, rather than local neural activity. These findings contribute to a deeper the understanding of the motor acuity and its underlying neural mechanism during training. |
