High-resolution three-dimensional microelectrode brain mapping using stereo microfocal X-ray imaging.

Area of Science:

• Neuroscience
• Medical Imaging
• Biophysics

Background:

• In vivo neuronal recordings are crucial for understanding brain function.
• Accurate 3D localization of microelectrode tips is challenging, limiting spatial mapping of brain areas, especially deep structures.

Purpose of the Study:

• To present a practical digital stereo microfocal X-ray imaging method for real-time 3D localization of microelectrode recording sites.
• To enable precise coregistration of electrophysiology data with anatomical references.

Main Methods:

• Digital stereo microfocal X-ray imaging for real-time 3D position estimation of microelectrode tips.
• Ex vivo and in vivo experiments to validate localization accuracy and coregistration.
• Coregistration of microelectrode sites with magnetic resonance images (MRIs).

Main Results:

• Achieved ex vivo localization accuracy better than 50 micrometers.
• Successfully coregistered hundreds of deep-brain microelectrode recordings in monkeys to a common reference frame with a median error of <150 micrometers.
• Demonstrated coregistration of recording sites with MRIs for anatomical comparison.

Conclusions:

• The developed X-ray imaging method provides accurate, real-time 3D localization of microelectrode recording sites.
• This technique bridges the gap between single-cell electrophysiology and spatial imaging, enabling high-resolution brain mapping.
• The method lays the foundation for advanced electrophysiology/fMRI comparisons and novel functional brain mapping.