A System for Serial Reconstruction In the early 1980's, the Laboratory for Retinal Microcircuitry developed a system for 3D reconstruction of neural circuitry based on computer analysis of a series of electron micrographs. A series of a dozen to several hundred thin (100 nm) sections is prepared and photographed in the electron microscope using methods designed in our laboratory (see below). The series contains sufficient information to make a complete reconstruction of a small block of neural tissue. The researcher follows the processes of a neuron from one section to the next on an enlargement of the EM negative, tracing the outlines of the cell membrane onto sheets of clear plastic mounted on a cartoonist's jig. This allows the position of one neural processes to be compared between adjacent sections. Alignment of each successive section is accomplished by the use of "fiducial processes" which are neural outlines near (but not associated with) the one being reconstructed. The researcher aligns successive sections using the fiducial processes as a guide. This corrects distortions between sections, and eliminates any irregularities caused by the EM sectioning, giving an accurate 3D reconstruction of the cell morphology. The Montage package Once a neuron's 3D outline has been traced through the EM series, it is entered into a computer with a digitizing tablet using the Montage program. The result is a data file with a series of polygons representing the cell's outline through the EM series. The Montage 3D reconstruction system, developed in this laboratory, contains programs for 3D reconstruction data entry, display and analysis. The source code for the Montage serial reconstruction system is available by anonymous ftp to retina.anatomy.upenn.edu. For more information on the methods involved in our 3D reconstruction method, see these two papers: Stevens, John K., Thomas L. Davis, Neil Friedman, and Peter Sterling."A Systematic Approach to Reconstructing Microcircuitry by Electron Microscopy of Serial Sections". John K. Stevens, Thomas L. Davis, Neil Friedman, and Peter Sterling. Brain Research Reviews, 2 (1980): 265-293. Smith, Robert G. "Montage: a system for three-dimensional reconstruction by personal computer". Journal of Neuroscience Methods. 21 (1987) 55-69. | Home | Lab Members | Research Goals & Methods | Abstracts | | Serial Reconstructions | Useful Links | How to Contact Us |