High bandwidth all-optical electrophysiology

In systems neuroscience, many “dream experiments” depend on the ability to simultaneously record from thousands of neurons in vivo, often across multiple cortical layers or subcortical regions, while also being able to selectively induce activity patterns in subsets of these same neurons. While advances in genetically-encoded calcium indicators and optogenetic channels (i.e., opsins) and their expression mechanisms make such experiments theoretically possible, optical microscopes necessary to fully support these experiments do not yet exist. 3i seeks to establish the feasibility of combining recent advances in optical techniques to produce a commercial instrument that fully harnesses these biological innovations to actualize the dream experiments through large-scale all-optical electrophysiology. Significant academic research has already been conducted in two distinct areas of photonics: 1) volumetric imaging of neuroactivity at physiologically relevant rates and cellular resolution, and 2) using computer-generated holography to selectively activate optogenetically-labeled neurons within similar volumes. However, most work in volumetric functional imaging has not included real-time optical neuro- stimulation, and most work in 3D stimulation has been paired with conventional single-plane imaging. 3i is in a unique position to merge cutting-edge techniques in these two areas and produce an instrument that would enable optical manipulation and unbiased recording of the activity of all labeled neurons within a target volume that spans multiple layers of mammalian cortex or subcortical regions. The proposed Phase I project is submitted in response to the NIH Notice of Special Interest (NOSI): “Translation of BRAIN Initiative Technologies to the Marketplace (NOT-MH-24-115)” and addresses two priority areas for technology commercialization: “Monitor Neural Activity” and “Interventional Tools.” 3i was first to commercialize computer-generated holography for neural stimulation and has sold over 60 systems. Further, 3i has exclusively licensed and implemented two new forms of 3D holography that are well suited to multi-cell stimulation at physiological timescales: MTF-CGH, developed by the Emiliani lab at the Vision Institute, and 3D-SHOT, developed by the Adesnik lab at UC Berkeley, both of which received BRAIN Initiative funding. In 2019, 3i began a collaboration with the Vaziri lab at Rockefeller to produce a commercial version of their scanned temporal focusing (s-TeFo) microscope, also funded by BRAIN, and has since installed a prototype system there. This microscope can measure calcium responses from thousands of neurons spanning multiple cortical layers, at speeds reaching tens of Hertz. In addition to proving the feasibility of such a combination through in vitro evaluation, 3i proposes to perform preliminary experiments in collaboration with the labs of Dr Diego Restrepo and Dr Emily Gibson, at the University of Colorado Anschutz Medical Campus, to assess its suitability in vivo.