Faculty of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel.
Faculty of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel.
Cell Rep. 2023 Mar 28;42(3):112214. doi: 10.1016/j.celrep.2023.112214. Epub 2023 Mar 14.
Finger dexterity is manifested by coordinated patterns of muscle activity and generalization of learning across contexts. Some fingers flex, others extend, and some are immobile. Whether or not the neural control processes of these direction-specific actions are independent remains unclear. We characterized behavioral principles underlying learning and generalization of dexterous flexion and extension movements, within and across hands, using an isometric dexterity task that precisely measured finger individuation, force accuracy, and temporal synchronization. Two cohorts of participants trained for 3 days in either the flexion or extension direction. All dexterity measures in both groups showed post-training improvement, although finger extension exhibited inferior dexterity. Surprisingly, learning of finger extension generalized to the untrained flexion direction, but not vice versa. This flexion bias was also evident in the untrained hand. Our study indicates direction-specific control circuits for learning of finger flexion and extension that interact by partially, but asymmetrically, transferring between directions.
手指的灵活性表现为肌肉活动的协调模式和跨情境的学习泛化。有些手指弯曲，有些伸展，有些则保持不动。这些特定方向动作的神经控制过程是否独立尚不清楚。我们使用等长灵巧任务来描述灵巧的弯曲和伸展运动在手部内部和之间的学习和泛化的行为原则，该任务可以精确测量手指的个体化、力的准确性和时间同步性。两组参与者分别在弯曲或伸展方向上训练 3 天。两组的所有灵巧度指标在训练后都有所提高，尽管手指伸展的灵巧度较差。令人惊讶的是，手指伸展的学习可以泛化到未训练的弯曲方向，但反之则不行。这种弯曲偏好在手未训练时也很明显。我们的研究表明，手指弯曲和伸展的学习具有特定的控制回路，它们通过在方向之间部分但不对称地传递来相互作用。
