Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AZ, UK.
Dani Clode design, 40 Hillside Road, London SW2 3HW, UK.
Sci Robot. 2021 May 19;6(54). doi: 10.1126/scirobotics.abd7935.
Humans have long been fascinated by the opportunities afforded through augmentation. This vision not only depends on technological innovations but also critically relies on our brain's ability to learn, adapt, and interface with augmentation devices. Here, we investigated whether successful motor augmentation with an extra robotic thumb can be achieved and what its implications are on the neural representation and function of the biological hand. Able-bodied participants were trained to use an extra robotic thumb (called the Third Thumb) over 5 days, including both lab-based and unstructured daily use. We challenged participants to complete normally bimanual tasks using only the augmented hand and examined their ability to develop hand-robot interactions. Participants were tested on a variety of behavioral and brain imaging tests, designed to interrogate the augmented hand's representation before and after the training. Training improved Third Thumb motor control, dexterity, and hand-robot coordination, even when cognitive load was increased or when vision was occluded. It also resulted in increased sense of embodiment over the Third Thumb. Consequently, augmentation influenced key aspects of hand representation and motor control. Third Thumb usage weakened natural kinematic synergies of the biological hand. Furthermore, brain decoding revealed a mild collapse of the augmented hand's motor representation after training, even while the Third Thumb was not worn. Together, our findings demonstrate that motor augmentation can be readily achieved, with potential for flexible use, reduced cognitive reliance, and increased sense of embodiment. Yet, augmentation may incur changes to the biological hand representation. Such neurocognitive consequences are crucial for successful implementation of future augmentation technologies.
人类长期以来一直对增强技术带来的机会着迷。这种愿景不仅依赖于技术创新，还严重依赖于我们的大脑学习、适应和与增强设备接口的能力。在这里，我们研究了是否可以通过额外的机器人拇指实现成功的运动增强，以及它对生物手的神经表示和功能的影响。健康参与者在 5 天内接受了额外的机器人拇指（称为第三拇指）的训练，包括实验室基础训练和非结构化日常使用。我们要求参与者仅使用增强后的手完成通常的双手任务，并检查他们开发手-机器人交互的能力。参与者接受了各种行为和脑成像测试，旨在在训练前后研究增强手的表示。训练提高了第三拇指的运动控制、灵巧性和手-机器人协调性，即使在认知负荷增加或视觉被遮挡时也是如此。它还增加了对第三拇指的体现感。因此，增强技术影响了手表示和运动控制的关键方面。第三拇指的使用削弱了生物手的自然运动协同作用。此外，大脑解码显示，即使不佩戴第三拇指，训练后其运动表示也会轻微崩溃。总之，我们的研究结果表明，运动增强可以很容易地实现，具有灵活使用、降低认知依赖和增强体现感的潜力。然而，增强技术可能会对手的表示产生变化。这些神经认知后果对于成功实施未来的增强技术至关重要。
