Effects of Intracortical Microstimulation on Neural Activity in Distant Cortical Regions

电刺激已被证明是一种向大脑传递信息的有用技术 从脑机接口技术。大脑非常有能力学习解释这种 信息，最明显的证明是人工耳蜗植入的成功。学习翻译刺激 转化为有用的信息可以归因于神经可塑性，但很少有人知道之间的关系， 局部电刺激和随后对远离模拟部位的大脑区域的影响。在 刺激皮质灰质或皮质内微刺激（ICMS）的特定背景， 假设后刺激效应仍然局限于刺激附近的小体积神经元， 电极上然而，有证据表明，这种影响可以传播很远。 在我的实验室之前的工作表明，受试者可以学习解释ICMS传递到四个不同的 电极在初级躯体感觉皮层（S1）作为指令执行四个不同的任意- 指定的动作。我使用该数据集进行的初步研究表明，在S1中提供的ICMS可能具有 ICMS脉冲对远侧皮层神经元的作用有两种类型：1）ICMS脉冲可直接在神经元中引起棘波 从腹侧前运动皮层（PMv）和初级运动皮层（M1）-或者是逆向的， 单突触或寡突触-我称之为“直接驱动”。2)其他神经元不直接由 尽管如此，ICMS脉冲可能会在仅用列车指示相同运动的试验之间以不同的方式发射 ICMS脉冲与只有视觉提示相比，我称之为“视觉-模态依赖性调制”。因此，在本发明中， ICMS的影响可能会延伸到比以前认识到的更远的皮层网络部分。 我建议调查的影响ICMS指令的任意关联运动交付 在S1的几个遥远的皮质区参与运动控制。具体来说，我将研究七个正面的影响， 顶叶区：前辅助运动区，背侧运动前区，腹侧运动前区，吻侧 初级运动皮层、尾侧初级运动皮层、前顶内区和背侧后顶区 皮层目的我将检查哪些皮层区域包含直接由ICMS脉冲驱动的神经元 在S1中交付。目标二将检查哪些皮层区域包含显示指令的神经元- 模态依赖调制拟议的研究将显示S1中ICMS调节 皮层网络的远端部分，以及当受试者学习使用大脑皮层时，这种调制是如何随着时间的推移而发展的。 ICMS作为执行任意关联运动的指令。这些信息可以用来设计 从脑机接口技术输入到皮层，对受试者来说更清楚， 健康的可塑性，以减少训练过程中的认知需求。这些改进有助于 患有可以用脑机接口技术治疗的神经系统疾病的患者 包括中风、感觉神经病或头部创伤。

Electrical stimulation has been shown to be a useful technique for delivering information to the brain from brain-machine interfacing technology. The brain is remarkably capable of learning to interpret such information, most notably demonstrated by the success of cochlear implants. Learning to translate stimulation into useful information can be attributed to neural plasticity, yet little is known about the relationship between localized electrical stimulation and subsequent effects on brain regions distant from the simulation site. In the specific context of stimulating cortical gray matter, or intracortical microstimulation (ICMS), a common assumption is that post-stimulation effects remain localized to a small volume of neurons near the stimulating electrode. However, there is evidence that suggests the effects can spread substantial distances. Prior work in my lab has shown that subjects can learn to interpret ICMS delivered to four different electrodes in the primary somatosensory cortex (S1) as instructions to perform four different arbitrarily- assigned movements. My preliminary studies using that dataset suggest that ICMS delivered in S1 can have two types of effects on neurons in distant cortical areas: 1) ICMS pulses can directly elicit spikes in neurons from both ventral premotor cortex (PMv) and primary motor cortex (M1) – either antidromically, monosynaptically, or oligosynaptically – which I term “direct driving”. 2) Other neurons not directly driven by the ICMS pulses may nevertheless fire differently between trials instructing the same movements with only trains of ICMS pulses versus with only visual cues, which I term “instruction-modality dependent modulation”. Thus, the effects of ICMS may extend to parts of the cortical network more distant than previously appreciated. I propose to investigate the effects of ICMS instructions for arbitrarily-associated movements delivered in S1 on several distant cortical areas involved in motor control. Specifically, I will study effects in seven frontal and parietal regions: pre-supplementary motor area, dorsal premotor cortex, ventral premotor cortex, rostral primary motor cortex, caudal primary motor cortex, anterior intraparietal area, and dorsal posterior parietal cortex. Aim I will examine which of those cortical areas contain neurons that are directly driven by ICMS pulses delivered in S1. Aim II will examine which of those cortical areas contain neurons that show instruction- modality dependent modulation. The proposed studies will show the extent to which ICMS in S1 modulates distant parts of the cortical network, and how such modulation develops over time as subjects learn to use the ICMS as instructions to perform arbitrarily-associated movements. That information can be used to design inputs to cortex from brain-machine interfacing technology that is clearer to the subject and encourages healthy plasticity to reduce cognitive demand during the training process. Those improvements serve to benefit patients with diseases of the nervous system that can be treated with brain-machine interfacing technology including stroke, sensory neuropathies, or head trauma.