Yang, M.; Zhou, Z.-Q.; Lang, S.; Zheng, H.; Chen, S.; Li, T.; Stas, E.; Zhang, L.; Zhang, Z.; Uzungil, V.; Liu, Q.; Huang, Y.; Jing, L.; Li, Y.; Jia, H.; Li, M.; Li, X.; Li, J.; Tan, Y.; Yan, G.; Schultz, S. R.

Observing the activity patterns of large neural populations throughout the brain is essential for understanding neural functions. However, capturing neural interactions across widely distributed brain regions, including both superficial and deep cortical layers, remains challenging with existing microscopy technologies. Here, we introduce a state-of-the-art two-photon microscopy system capable of single-cell resolution imaging across an ultra-large field of view (FOV) exceeding 50 mm2, enabling deep in vivo imaging. To demonstrate its capabilities, we conducted a series of experiments under multiple imaging conditions, successfully visualizing brain structures and neuronal activities spanning a wide spatial range (> 7 mm) from superficial layers to depth reaching up to 900 um in the mouse brain. This versatile imaging platform overcomes traditional spatial constraints, providing a powerful tool for comprehensive exploration of neuronal circuitry over extensive spatial scales with cellular resolution.