Photoemission electron microscopy for connectomics

bioRxiv (Cold Spring Harbor Laboratory)

Abstract

Detailing the physical basis of neural circuits with large-volume serial electron microscopy (EM), 'connectomics', has emerged as an invaluable tool in the neuroscience armamentarium. However, imaging synaptic resolution connectomes is currently limited to either transmission electron microscopy (TEM) or scanning electron microscopy (SEM). Here, we describe a third way, using photoemission electron microscopy (PEEM) which illuminates ultra-thin brain slices collected on solid substrates with UV light and images the photoelectron emission pattern with a wide-field electron microscope. PEEM works with existing sample preparations for EM and routinely provides sufficient resolution and contrast to reveal myelinated axons, somata, dendrites, and sub-cellular organelles. Under optimized conditions, PEEM provides synaptic resolution; and simulation and experiments show that PEEM can be transformatively fast, at Gigahertz pixel rates. We conclude that PEEM imaging leverages attractive aspects of SEM and TEM, namely reliable sample collection on robust substrates combined with fast wide-field imaging, and could enable faster data acquisition for next-generation circuit mapping.

Authors 9

1. Kevin M. Boergens corresponding

   University of Illinois Urbana-Champaign · University of Illinois Chicago

   Affiliation as printed

   Department of Physics, University of Illinois, Chicago

   Department of Physics, University of Illinois

2. Gregg A. Wildenberg corresponding

   Argonne National Laboratory · University of Chicago

   Affiliation as printed

   Argonne National Laboratory, Lemont, IL

   Department of Neurobiology, University of Chicago

3. Ruiyu Li

   University of Chicago

   Affiliation as printed

   Department of Chemistry, University of Chicago

   James Franck Institute, University of Chicago

4. Lola Lambert

   University of Chicago

   Affiliation as printed

   Department of Neurobiology, University of Chicago

5. Amin Moradi Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University

6. Rudolf M. Tromp Aachen

   Leiden University · IBM Research - Thomas J. Watson Research Center

   Affiliation as printed

   IBM T.J. Watson Research Center

   Leiden Institute of Physics, Leiden University

7. Sense Jan van der Molen Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University

8. Sarah B. King

   University of Chicago

   Affiliation as printed

   Department of Chemistry, University of Chicago

   James Franck Institute, University of Chicago

9. Narayanan Kasthuri

   Argonne National Laboratory · University of Chicago

   Affiliation as printed

   Argonne National Laboratory, Lemont, IL

   Department of Neurobiology, University of Chicago