Single 5 μm diameter needle electrode block modules for unit recordings in vivo

• Published in: Scientific reports Vol. 6; no. 1; p. 35806
• Main Authors: Sawahata, H., Yamagiwa, S., Moriya, A., Dong, T., Oi, H., Ando, Y., Numano, R., Ishida, M., Koida, K., Kawano, T.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25.10.2016; Nature Publishing Group
• Subjects: 631/1647/1453/2205; 639/166/985; Animals; Electric Impedance; Electrodes, Implanted; Equipment Design; Humanities and Social Sciences; Male; Mice; Microelectrodes; multidisciplinary; Neurons - physiology; Photic Stimulation; Science; Single-Cell Analysis - instrumentation; Single-Cell Analysis - methods; Somatosensory Cortex - physiology; Visual Cortex - cytology; Visual Cortex - physiology
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep35806

Investigations into mechanisms in various cortical areas can be greatly improved and supported by stable recording of single neuronal activity. In this study, fine silicon wire electrodes (diameter 3 μm, length 160 μm) are fabricated by vapor–liquid–solid (VLS) growth with the aim of stabilizing recording and reducing the invasiveness on the measurement procedure. The electrode is fabricated on a modular 1 ×  1 mm 2 conductive silicon block that can be assembled into a number of different device packages, for example on rigid or flexible printed circuit boards (PCB). After plating with a 5 μm diameter platinum black, the needle exhibits an electrical impedance of ~100 kΩ at 1 kHz in saline. The in vivo recording capability of the device is demonstrated using mice, and spike signals with peak-to-peak amplitudes of 200−300 μV in the range 0.5−3 kHz are stably detected, including single-unit activities in cortical layer 2/3. In addition, the device packaged with a flexible PCB shows stable unit recordings for 98.5 min (n = 4). Consequently, our modular, low-invasive needle electrode block devices present an effective route for single-unit recordings in vivo , as well as demonstrating adaptability in device design for a diverse range of experiments.