Application of the mirror technique for block-face scanning electron microscopy

Area of Science:

• Neuroscience
• Microscopy
• Cell Biology

Background:

• The mirror technique correlates neuronal structures across light microscopic sections.
• Current limitations restrict this technique to thin sections (<100 µm).
• Investigating neurochemical structures requires correlating with larger tissue blocks.

Purpose of the Study:

• To extend the mirror technique for use with millimeter-sized tissue blocks.
• To demonstrate compatibility with serial block-face electron microscopy (SBEM).
• To enable correlation of neuronal structures across larger tissue sections for detailed analysis.

Main Methods:

• Modified the mirror technique for larger tissue blocks (millimeter range).
• Ensured compatibility with serial block-face electron microscopy (SBEM).
• Developed a method to remove unbound resin for improved surface visibility during curing.

Main Results:

• Successfully applied the enhanced mirror technique to millimeter-sized tissue blocks.
• Demonstrated unequivocal identification of neuronal cell bodies using epi-illumination and confocal microscopy.
• Enabled correlation of cell body layout with complementary sections for immunohistochemistry.

Conclusions:

• The modified mirror technique overcomes spatial limitations for synaptology investigation.
• Facilitates detailed analysis of neurochemically identified neuronal processes, dendrites, and axons.
• Provides a powerful tool for high-resolution neuroanatomical and neurochemical studies.