Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
J Neural Eng. 2014 Feb;11(1):016010. doi: 10.1088/1741-2560/11/1/016010. Epub 2014 Jan 20.
Spatial localization of neural activity from within the brain with electrocorticography (ECoG) and electroencephalography remains a challenge in clinical and research settings, and while microfabricated ECoG (micro-ECoG) array technology continues to improve, complementary methods to simultaneously modulate cortical activity while recording are needed.
We developed a neural interface utilizing optogenetics, cranial windowing, and micro-ECoG arrays fabricated on a transparent polymer. This approach enabled us to directly modulate neural activity at known locations around micro-ECoG arrays in mice expressing Channelrhodopsin-2. We applied photostimuli varying in time, space and frequency to the cortical surface, and we targeted multiple depths within the cortex using an optical fiber while recording micro-ECoG signals.
Negative potentials of up to 1.5 mV were evoked by photostimuli applied to the entire cortical window, while focally applied photostimuli evoked spatially localized micro-ECoG potentials. Two simultaneously applied focal stimuli could be separated, depending on the distance between them. Photostimuli applied within the cortex with an optical fiber evoked more complex micro-ECoG potentials with multiple positive and negative peaks whose relative amplitudes depended on the depth of the fiber.
Optogenetic ECoG has potential applications in the study of epilepsy, cortical dynamics, and neuroprostheses.
用电皮质图（ECoG）和脑电图对大脑内的神经活动进行空间定位在临床和研究环境中仍然是一个挑战，虽然微制造的 ECoG（微 ECoG）阵列技术在不断改进，但仍需要同时调节皮质活动并进行记录的互补方法。
我们开发了一种利用光遗传学、颅窗和在透明聚合物上制造的微 ECoG 阵列的神经接口。这种方法使我们能够在表达通道视紫红质-2 的小鼠的微 ECoG 阵列周围的已知位置直接调节神经活动。我们在记录微 ECoG 信号的同时，在皮质表面施加时间、空间和频率不同的光刺激，并用光纤靶向皮质内的多个深度。
光刺激施加到整个皮质窗口时会引起高达 1.5 mV 的负电位，而聚焦施加的光刺激会引起空间定位的微 ECoG 电位。两个同时施加的焦点刺激可以根据它们之间的距离分开。用光纤在皮层内施加光刺激会引起更复杂的微 ECoG 电位，具有多个正负极，其相对幅度取决于光纤的深度。
光遗传 ECoG 在癫痫、皮质动力学和神经假体研究中有潜在的应用。
