Cognitive signals for brain-machine interfaces in posterior parietal cortex include continuous 3D trajectory commands
Cognitive signals for brain-machine interfaces in posterior parietal cortex include continuous 3D trajectory commands
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DOI：
10.1073/pnas.1215092109
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发表时间：
2012-10-16
影响因子：
11.1
通讯作者：
Andersen, Richard A.
中科院分区：
文献类型：
--
作者：
Hauschild, Markus;Mulliken, Grant H.;Andersen, Richard A.
皮质神经假体从大脑提取命令信号，目的是恢复瘫痪或截肢患者的功能。连续的控制信号可以从运动皮质区域提取，而来自后顶叶皮质(PPC)的神经活动可以用来解码与运动目标相关的认知变量。由于日常生活的典型活动既包括连续的控制任务，如伸手，也包括受益于离散控制的任务，如在键盘上打字，因此同时使用这两种信号将有望显著提高性能和多功能性。在这里，我们展示了PPC可以在假肢应用中遇到的自然条件下提供3D手部轨迹信息，从而允许同时提取连续和离散信号，而不需要多部位外科植入。我们发现，在复杂的3D点对点到达任务中，在自由凝视下的一小部分神经单元中，肢体运动可以被稳健且高精度地解码。随着练习的进行，两种动物的大脑控制能力都得到了迅速的提高，从而更快地获得了目标，提高了准确性。这些发现驳斥了运动皮质区域是持续假肢指令信号的唯一候选区域的观点，相反，表明PPC除了提供离散的认知变量外，还可以提供同样有用的轨迹信号。来自PPC的连续和离散信号的混合使用可以实现新一代神经假体，在满足个体患者需求方面提供卓越的性能和额外的灵活性。
Cortical neural prosthetics extract command signals from the brain with the goal to restore function in paralyzed or amputated patients. Continuous control signals can be extracted from the motor cortical areas, whereas neural activity from posterior parietal cortex (PPC) can be used to decode cognitive variables related to the goals of movement. Because typical activities of daily living comprise both continuous control tasks such as reaching, and tasks benefiting from discrete control such as typing on a keyboard, availability of both signals simultaneously would promise significant increases in performance and versatility. Here, we show that PPC can provide 3D hand trajectory information under natural conditions that would be encountered for prosthetic applications, thus allowing simultaneous extraction of continuous and discrete signals without requiring multisite surgical implants. We found that limb movements can be decoded robustly and with high accuracy from a small population of neural units under free gaze in a complex 3D point-to-point reaching task. Both animals' brain-control performance improved rapidly with practice, resulting in faster target acquisition and increasing accuracy. These findings disprove the notion that the motor cortical areas are the only candidate areas for continuous prosthetic command signals and, rather, suggests that PPC can provide equally useful trajectory signals in addition to discrete, cognitive variables. Hybrid use of continuous and discrete signals from PPC may enable a new generation of neural prostheses providing superior performance and additional flexibility in addressing individual patient needs.