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The ability to both induce and monitor neural activity at cellular resolution is necessary to comprehend the activation paradigm in sensory processing and for the development of effective neuromodulation treatments. Our lab has produced an actuator-sensor construct via the hybridization of an optogenetic actuator (bMCOII) and bioluminescent Ca2+ sensor (GeNL) which allows continuous monitoring of neural activity with high spatiotemporal resolution. Modeling revealed that the construct is bound to the cell membrane through 14 transmembrane helices with the Ca2+ -bioluminescence indicator domain 20-40 Å inside the cytoplasm (membrane localization confirmed by imaging). The construct can be used to stimulate neural activity with very low intensity (10 μW/mm2 ) light but unlike fluorescent methods, requires no excitation light. Activation of the opsin causes influx of Ca2+ by opening MCOII-channels via trans-cis isomerization of all-trans-retinal. When these ions bind the indicator domain there is an increase in bioluminescence intensity. We observed significant correlation between the magnitude and kinetics of induced electrical activities and Ca2+ -bioluminescence. Longterm (>14 hours) recording of evoked neural activity in the visual cortices of murine models allowed the quantification of the strength of sensory activation. Additionally, through Artificial Intelligence-based Neural Activation Parameters, the Ca2+ -bioluminescence signals were used to map network activity patterns. We also observed delayed, secondary Ca2+ - bioluminescence responses murine visual cortices. These may be astrocyte-mediated responses to direct optogenetic and indirect visual stimulation. Our technique will enable the development of a scalable, and modular interface system which can be expanded to monitor and modulate a variety of neurological activities.
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