School of Engineering, Brown University, Providence, RI, USA.
Electrical and Computer Engineering, Baylor University, Waco, TX, USA.
Nat Commun. 2024 Nov 21;15(1):10093. doi: 10.1038/s41467-024-54542-1.
Transmitting meaningful information into brain circuits by electronic means is a challenge facing brain-computer interfaces. A key goal is to find an approach to inject spatially structured local current stimuli across swaths of sensory areas of the cortex. Here, we introduce a wireless approach to multipoint patterned electrical microstimulation by a spatially distributed epicortically implanted network of silicon microchips to target specific areas of the cortex. Each sub-millimeter-sized microchip harvests energy from an external radio-frequency source and converts this into biphasic current injected focally into tissue by a pair of integrated microwires. The amplitude, period, and repetition rate of injected current from each chip are controlled across the implant network by implementing a pre-scheduled, collision-free bitmap wireless communication protocol featuring sub-millisecond latency. As a proof-of-concept technology demonstration, a network of 30 wireless stimulators was chronically implanted into motor and sensory areas of the cortex in a freely moving rat for three months. We explored the effects of patterned intracortical electrical stimulation on trained animal behavior at average RF powers well below regulatory safety limits.
通过电子手段将有意义的信息传递到大脑回路是脑机接口面临的一个挑战。一个关键目标是找到一种方法，在皮层的感觉区域中大面积地注入空间结构的局部电流刺激。在这里，我们引入了一种无线方法，通过空间分布的皮层内植入的硅微芯片网络对特定的皮层区域进行多点模式化的电微刺激。每个亚毫米大小的微芯片从外部射频源中获取能量，并通过一对集成的微丝将其转换为双相电流，聚焦注入组织。通过实现一种具有亚毫秒延迟的预调度、无冲突位图无线通信协议，可以在植入网络中控制每个芯片的注入电流的幅度、周期和重复率。作为概念验证技术演示，一个由 30 个无线刺激器组成的网络被慢性植入到自由移动大鼠的运动和感觉皮层中，持续了三个月。我们在平均射频功率远低于监管安全限制的情况下，探索了模式化皮层内电刺激对训练动物行为的影响。
