Large field-of-view volumetric multiphoton calcium imaging through GRIN lenses

The brain is the most complex organ, and understanding its functions is crucial for both medicine and artificial intelligence. Recent advances in neurophotonics have enabled the observation and manipulation of individual neurons in the mammalian brain, providing valuable insights into neuronal activity. However, a major challenge is the limited depth of light penetration due to tissue scattering, restricting imaging to superficial regions. Currently, the GRIN lens is the most commonly used solution to image deep brain regions. However, due to its inherent aberrations, the achievable imaging FOV is very small, which limits the measurement throughput and success rate. To overcome this problem, my team developed optical engineering solutions that eliminate astigmatism and field curvature in GRIN lenses, enabling high-throughput volumetric recordings with unprecedented performance. I will present these solutions and their effectiveness for deep brain imaging.