Long-Term Stability of Motor Cortical Activity: Implications for Brain Machine Interfaces and Optimal Feedback Control
Long-Term Stability of Motor Cortical Activity: Implications for Brain Machine Interfaces and Optimal Feedback Control
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DOI：
10.1523/jneurosci.2339-15.2016
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发表时间：
2016-03-23
影响因子：
5.3
通讯作者：
Slutzky, Marc W.
中科院分区：
文献类型：
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作者：
Flint, Robert D.;Scheid, Michael R.;Slutzky, Marc W.
人类的运动系统能够非常精确地控制运动——想想职业棒球投手或外科医生的技术。这种精确的控制依赖于大脑中运动的稳定表征。在此，我们通过记录局部场电位（LFPs）和动作电位（多单元峰电位，MSPs），研究了两只猴子在多个时空尺度上皮层活动的稳定性，而两只猴子分别用手或直接通过脑机接口从大脑控制光标。lfp和一些msp在3至3年的时间内非常稳定；总体而言，lfp明显比峰值更稳定。然后，我们评估是否所有神经活动的稳定性，或者只是活动的一个子集，是实现稳定行为所必需的。我们发现，神经活动投射到与任务相关的子空间（“任务相关空间”）比投射到任务无关（或“任务空”）空间要稳定得多。这为支持最小干预原则提供了皮层证据，该原则提出，最优反馈控制（OFC）允许大脑严格控制任务相关空间的活动，而允许任务无关空间的活动在不同的试验中发生很大变化。我们发现，大脑似乎能够在很长一段时间内保持稳定的运动表征，尤其是与任务相关的神经活动，这与OFC的预测一致。
The human motor system is capable of remarkably precise control of movements-consider the skill of professional baseball pitchers or surgeons. This precise control relies upon stable representations of movements in the brain. Here, we investigated the stability of cortical activity at multiple spatial and temporal scales by recording local field potentials (LFPs) and action potentials (multiunit spikes, MSPs) while two monkeys controlled a cursor either with their hand or directly from the brain using a brain-machine interface. LFPs and some MSPs were remarkably stable over time periods ranging from 3d to over 3 years; overall, LFPs were significantly more stable than spikes. We then assessed whether the stability of all neural activity, or just a subset of activity, was necessary to achieve stable behavior. We showed that projections of neural activity into the subspace relevant to the task (the "task-relevant space") were significantly more stable than were projections into the task-irrelevant (or "task-null") space. This provides cortical evidence in support of the minimum intervention principle, which proposes that optimal feedback control (OFC) allows the brain to tightly control only activity in the task-relevant space while allowing activity in the task-irrelevant space to vary substantially from trial to trial. We found that the brain appears capable of maintaining stable movement representations for extremely long periods of time, particularly so for neural activity in the task-relevant space, which agrees with OFC predictions.