Stimulation-artifact-free, high-spatiotemporal-resolution in vivo opto-electrophysiology with μLED optoelectrodes

In vivo extracellular electrophysiology and genetic-engineering-assisted optical stimulation combined ( in vivo opto-electrophysiology or optoEphys) has proven its great potential to be one of the best tools for study of the intricate networks inside the brain. Micro-LED optoelectrode, the Michigan Probe with monolithically integrated cell-sized LEDs, enabled in vivo optoEphys at the highest spatial resolution to date. However, high-magnitude stimulation artifact had prevented experiments from being conducted at a desirably high temporal resolution. Here, we report engineering schemes with which the magnitude of stimulation artifact generated from μLED optoelectrode can be greatly reduced for nearly artifact-free (V peak-to-peak in vivo experiments. The second-generation μLED optoelectrodes, fabricated using heavily boron-doped silicon wafer and equipped with dedicated EMI shielding layers, exhibited capability to record neuronal activities during fast-switched optical stimulations without degradation in signal quality. We believe that the novel μLED optoelectrodes will lead to exciting discoveries of the brain′s circuit-level mechanisms.