Multicolor two-photon light-patterning microscope exploiting the spatio-temporal properties of a fiber bundle

Abstract

The development of efficient genetically encoded indicators and actuators has opened up the possibility of reading and manipulating neuronal activity in living tissues with light. To achieve precise and reconfigurable targeting of large numbers of neurons with single-cell resolution within arbitrary volumes, different groups have recently developed all-optical strategies based on two-photon excitation and spatio-temporal shaping of ultrashort laser pulses. However, such techniques are often complex to set up and typically operate at a single wavelength only. To address these issues, we have developed a novel optical approach that uses a fiber bundle and a spatial light modulator to achieve simple and dual-color two-photon light patterning in three dimensions. By leveraging the core-to-core temporal delay and the wavelength-independent divergence characteristics of fiber bundles, we have demonstrated the capacity to generate high-resolution excitation spots in a 3D region with two distinct laser wavelengths simultaneously, offering a suitable and simple alternative for precise multicolor cell targeting.

Introduction to the Optics and the Brain 2023 feature issue

“…The authors’ novel design shows better performance with reduced aberrations. Another work [ 8 ] demonstrated a simple design for two-photon optogenetic holographic stimulation with multiple laser wavelengths, a fiber bundle, and spatial light modulator. The simplified approach can be used to perform scanless two-photon imaging combined with optogenetic stimulation to modulate and record activity at the individual neuron-level.…”