Three photon microscopy of mouse brain structure and function at 2 mm depth and beyond.

Area of Science:

• Neuroscience
• Biomedical Imaging
• Optical Microscopy

Background:

• Understanding brain function requires high-resolution, noninvasive imaging of neuronal activity deep within brain tissue.
• Current multiphoton microscopy techniques have limitations in imaging depth, hindering exploration of deeper brain structures.

Purpose of the Study:

• To develop and demonstrate an improved 1300-nm three-photon microscope capable of maximal excitation and collection efficiency.
• To achieve deep-tissue imaging of neuronal activity and brain vasculature at unprecedented depths in the intact mouse brain.

Main Methods:

• Utilized an improved 1300-nm three-photon microscopy platform engineered for maximal excitation and collection efficiency.
• Performed structural imaging of brain vasculature and functional imaging of neural activities in intact mouse brains.

Main Results:

• Achieved structural imaging of brain vasculature at depths up to 2.5 mm.
• Enabled functional imaging of neural activities at depths up to 2 mm, reaching previously inaccessible deep brain regions.
• Demonstrated imaging up to the theoretical three-photon depth limit.

Conclusions:

• The improved 1300-nm three-photon microscope significantly extends the frontier of deep-tissue functional imaging.
• This technology opens new possibilities for longitudinal and mechanistic studies in neuroscience and related fields.
• Enables noninvasive, single-cell resolution imaging deep within the brain.