A systematic approach to reconstructing microcircuitry by electron microscopy of serial sections

Area of Science:

• Neuroscience
• Electron Microscopy
• Computational Biology

Background:

• Reconstructing neurons from electron micrographs is crucial for understanding neuronal geometry and microcircuitry.
• Analyzing serial, ultra-thin sections presents significant technical challenges.

Purpose of the Study:

• To describe a novel approach for preparing, photographing, and analyzing moderately long series of electron micrographs for neuron reconstruction.
• To enable detailed quantitative analysis of neuronal structures.

Main Methods:

• Utilizing an assembly-line approach for section preparation and mounting.
• Employing low-magnification, high-accelerating voltage electron microscopy for image acquisition.
• Developing a "movie" format from sequential negatives, aligned and digitized using specialized equipment and a microprocessor for microalignment and coordinate storage.

Main Results:

• Achieved "microaligned" neuronal profiles with minimal frame-to-frame jitter.
• Stored alignment corrections as process vectors in a microprocessor.
• Demonstrated the generation of neuron "branch schematics" and digitized 3D reconstructions.

Conclusions:

• The described method provides an efficient and accurate approach for reconstructing neurons from serial electron micrographs.
• This technique facilitates detailed quantitative analysis of neuronal geometry and microcircuitry.
• The approach has been successfully applied to neuronal samples from the cat retina and visual cortex.