多通道在体记录技术----小鼠可推进式微电极阵列帽制作与植入手术

Multi-channel in vivo recording technique:Microdrive array fabrication and electrode implantation in mice

本文旨在探讨适合小鼠在体记录的多通道可推进式微电极阵列帽的制作和电极植入手术。利用转动螺杆驱动螺母移动的机械推进原理,用纤维板、螺杆、螺母和固定螺丝等材料,组装成可推进式多通道电极驱动装置。在该装置上,螺杆转动一圈可使其上的螺母移动280μm,从而使固定于其上的电极也同步推进。记录电极为自制的四电极,由四股直径为13μm的绝缘电极丝绞合而成。电极帽制作的主要步骤包括:四电极制作、电极驱动器制作、电极帽装配和电极镀金等步骤。制作好的多通道电极帽重量轻,电极数量可根据实验需要设置,且可随时调整电极在脑内的深浅位置,适合在小鼠等动物上开展多通道在体记录。此外,本文还详细介绍了在小鼠双侧海马进行多通道在体记录的电极植入手术过程。使用这种多通道电极帽,可在自由活动的小鼠双侧海马CA1脑区,同时记录到群体神经元的放电活动。

Here we describe and illustrate our methods for multi-channel in vivo recording in mice, including the fabrication of the microdrive array and the surgical procedure for implanting electrodes. The multi-channel microdrive is fabricated from printed circuit board base, screws, nuts and clamping screws. Rotation of the screw drives both the nut and the attached electrodes to move forward simultaneously. Each full turn of the screw corresponds to 280 μm in depth penetration. The recording electrodes are self-made tetrodes consisting 4 wires （13 μm in diameter）. The major steps of headstage fabrication include： tetrode making, microdrive construction, headstage assembling and tetrode plating. The finished headstage is suitable for multi-channel recording in freely moving rodents with the modest weight and the adjustable number of recording electrodes. Additionally, the recording site is allowed to be manipulated after implantation at any time. In the latter part of this paper, we introduce the procedure of the implant surgery to record in bilateral hippocampus in mice. Using these headstages, we simultaneously recorded population activity in bilateral CA1 in freely behaving mice.