Simultaneous three-photon and optical coherence microscopy deep within an intact mouse brain

Area of Science:

• Biomedical Engineering
• Neuroscience
• Optical Imaging

Background:

• Multimodal microscopy offers complementary tissue information in a single session.
• Combining imaging techniques enhances visualization capabilities for complex biological samples.

Purpose of the Study:

• To demonstrate a multimodal imaging approach combining three-photon microscopy (3PM) and spectral-domain optical coherence microscopy (SD-OCM).
• To showcase the simultaneous use of an optical parametric amplifier (OPA) laser source for 3PM, third harmonic generation (THG), and SD-OCM.
• To evaluate the system's performance for deep tissue imaging in vivo.

Main Methods:

• Utilized a multimodal microscopy system integrating 3PM and SD-OCM.
• Employed an optical parametric amplifier (OPA) laser source at a 1620 nm center wavelength.
• Performed in vivo imaging of deep mouse brains.

Main Results:

• Achieved simultaneous 3PM, THG, and SD-OCM imaging using a single OPA laser source.
• Visualized fine structures like myelinated axons, neurons, and fiber tracts at depths exceeding 1 mm in adult mouse brains.
• Demonstrated noninvasive imaging with high spatial resolution using combined linear and nonlinear contrast mechanisms.

Conclusions:

• Simultaneous OCM and 3PM at long wavelengths provide a powerful tool for deep tissue imaging in vivo.
• The demonstrated multimodal system offers a convenient and effective approach for neuroscience research.
• This technique advances noninvasive visualization of neural structures in the intact brain.