Understanding how cognitively-relevant behavioral functions emerge from activity patterns of identified cell- types is predicated on the ability to record large-scale ensemble dynamics from genetically-identified and longitudinally-tracked neuronal populations across multiple brain regions and layers with high spatial and temporal resolution over behaviorally-relevant time-scales. Two-photon scanning microscopy in combination with genetically-encoded calcium (Ca2+) indicators is currently the most essential tool for in vivo optical recording of neuronal activity, its application to deep brain regions. However, currently the commercially available 2pM systems are limited in their applications due to constraints related to the obtainable imaging depth, volumetric field-of-view (VFOV), and temporal resolution at which neuronal population dynamics can be effectively captured. We have recently developed and demonstrated the proof of principle of a new high-speed volumetric Ca2+-imaging platform termed Hybrid Multiplexed Sculpted Light (HyMS) Microscopy that combines 2pM with three-photon microscopy (3pM). HyMS allows for volumetric recording of neuroactivity at single-cell resolution within volumes up to ~1 1 1.22 mm at up to 17 Hz in cortical as well as sub-cortical regions of awake behaving mice. The impact of this tool will depend on a successful optimization, neurobiological application and dissemination strategy within the neuroscience community. While we will provide open source access for technically skilled labs, given the technical complexity and costs of such a system, the most effective strategy is through partnership with industry and through commercialization of the system. Here we propose a roadmap towards this objective. Building on our current existing system, we will implement a number of technical refinements and optimizations. Leveraging the ongoing collaboration with the Losonczy Lab at the Columbia University, we will use our optimized HyMS system to perform high-speed multiphoton volumetric Ca2+ imaging of functional circuitry across the entire depth of the mouse dorsal hippocampus (HPC), encompassing all major regions of the HPC trisynaptic circuitry. This application will provide us valuable feedback for further optimization and refinement and development of our HyMS prototype system. In parallel, we will develop together with our industrial partner a first prototype of the HyMS system (?-HyMS) This prototype will be again used and tested by the Losonczy Lab. The obtained insights and user feedback from their application will drive the development of a beta prototype (?-HyMS) which will be used to engage broader local users as beta testers. 9 user labs, mainly from the NYC area, with a broad range of biological questions and applications, will participate as beta testers and provide us with iterative user feedback which will ultimately drive and be incorporated both into the into the commercialization of HyMS as well its open source model of the access to this technology.
Understanding how behavioral functions emerge from activity patterns of neuronal populations across the brain at single cell is predicated on the ability to record simultaneously from large populations of neurons that make up the relevant networks. This remains an outstanding challenge due to lack of available tools and technologies. Our proposed roadmap to optimize, apply and widely disseminate a new technological imaging platform to the neuroscience community that can enable simultaneously recording of tens of thousands of neurons across cortical and subcortical depths has the potential to provide a major advance in our understanding how cognitively-relevant behavioral functions emerge from neuronal activity across distributed brain circuits.
