A wireless multichannel optogenetic headstage with on-the-fly spike detection

In this paper, we present a light-weight, wireless optogenetic headstage which provides optical neural stimulation and electrophysiological recording alongside on-the-fly neural signal processing. The proposed headstage is suitable to conduct long terms in-vivo experiments with small freely moving transgenic rodents, and features two implantable LED-coupled optical fibers and two electrophysiological recording channels while being powered by a small Lithium-ion battery. The headstage can transmit the raw neuronal signals or only spike waveforms after applying on-the-fly spike detection, which reduces power consumption by up to 14.5%. The headstage is entirely built using commercial off-the-shelf components, and the miniature design, using rigid-flex PCBs, results into a lightweight (7.4g) and compact device (25×20×15 mm). Low-power consumption is achieved by using on-the-fly spike detection alongside a real-time operating system which brings the headstage autonomy to 3h25 in full operation, including high-output power optical stimulation, micro-volts neuronal signal amplification and wireless transmission of the acquired waveforms.