INS-fOCT: a label-free, all-optical method for simultaneously manipulating and mapping brain function.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Optical Imaging

Background:

• Current brain stimulation and recording methods often require labels or invasive techniques.
• A need exists for label-free, all-optical approaches with high spatial and temporal resolution for brain function studies.

Purpose of the Study:

• To develop and validate a label-free, all-optical method for simultaneous brain manipulation and imaging.
• To utilize infrared stimulation (INS) and functional optical coherence tomography (fOCT) for real-time brain activity mapping.

Main Methods:

• A coregistered system integrating INS, fOCT, and optical intrinsic signal imaging (OISI) was constructed.
• Optical intrinsic signal imaging and electrophysiology recordings were used to validate fOCT signals.
• The system was tested for its ability to simultaneously stimulate and image neural activity.

Main Results:

• The fOCT signal demonstrated reliability and regional specificity, correlating directly with the INS-activated areas.
• fOCT signals were synchronous with INS onset, showing a linear relationship with stimulation intensity.
• Validation through OISI and electrophysiology confirmed the correlation between fOCT signals and INS-induced neural activity.

Conclusions:

• The developed fiber-based, all-optical INS-fOCT method enables simultaneous stimulation and mapping of brain function.
• This approach eliminates the need for contrast agents or viral transfection, reducing experimental complexity and risk.
• The technique offers deep penetration depth and high resolution, advancing label-free optical neuroscience tools.