Neurosciences Graduate Program, Stanford University, Stanford, CA, USA.
Department of Electrical Engineering, Stanford University, Stanford, CA, USA.
Nat Commun. 2021 Jun 17;12(1):3689. doi: 10.1038/s41467-021-23884-5.
Calcium imaging is a powerful tool for recording from large populations of neurons in vivo. Imaging in rhesus macaque motor cortex can enable the discovery of fundamental principles of motor cortical function and can inform the design of next generation brain-computer interfaces (BCIs). Surface two-photon imaging, however, cannot presently access somatic calcium signals of neurons from all layers of macaque motor cortex due to photon scattering. Here, we demonstrate an implant and imaging system capable of chronic, motion-stabilized two-photon imaging of neuronal calcium signals from macaques engaged in a motor task. By imaging apical dendrites, we achieved optical access to large populations of deep and superficial cortical neurons across dorsal premotor (PMd) and gyral primary motor (M1) cortices. Dendritic signals from individual neurons displayed tuning for different directions of arm movement. Combining several technical advances, we developed an optical BCI (oBCI) driven by these dendritic signalswhich successfully decoded movement direction online. By fusing two-photon functional imaging with CLARITY volumetric imaging, we verified that many imaged dendrites which contributed to oBCI decoding originated from layer 5 output neurons, including a putative Betz cell. This approach establishes new opportunities for studying motor control and designing BCIs via two photon imaging.
钙成像技术是一种强大的工具，可用于记录体内大量神经元的活动。在恒河猴运动皮层进行成像，可以帮助我们发现运动皮层功能的基本原理，并为下一代脑机接口（BCI）的设计提供信息。然而，由于光子散射，目前的表面双光子成像技术无法获取恒河猴运动皮层各层神经元的胞体钙信号。在这里，我们展示了一种植入式和成像系统，该系统能够对猕猴在执行运动任务时的神经元钙信号进行慢性、运动稳定的双光子成像。通过对树突进行成像，我们实现了对背侧运动前皮层（PMd）和脑回初级运动皮层（M1）中深层和浅层皮质神经元的大群体的光学访问。来自单个神经元的树突信号显示出对臂运动不同方向的调谐。通过结合几项技术进步，我们开发了一种由这些树突信号驱动的光学脑机接口（oBCI），该接口可在线成功解码运动方向。通过将双光子功能成像与 CLARITY 体积成像融合，我们验证了许多有助于 oBCI 解码的成像树突来自于 5 层的输出神经元，包括一个假定的贝茨细胞。这种方法通过双光子成像为研究运动控制和设计 BCI 提供了新的机会。
