X-Message-Number: 737
From:	Ralph Merkle <>
Subject: Re:  cryonics: #735 Brain Scan Question
Date:	Tue, 14 Apr 1992 17:51:32 PDT

You might be interested in "Large Scale Analysis of Neural Structures."  This
paper, available as Xerox PARC technical report (Blue & White) CSL-89-10,
discusses in reasonable detail the issues involved in high resolution imaging
of neural structures of a size up to and including the human brain by the
use of transmission electron microscopy.  The general context of this
discussion was research.  A complete analysis of a structure the size of the
human brain using what amounts to modest extensions to current technology
would be a project of rather large size (billions of dollars) and might
be comparable to going to the moon, sequencing the human genome, or the
construction of the superconducting super collider.  It should be feasible
within 20 years using nothing more than evolutionary advances in current
technology.  The major issue that would require resolution would be the

automated image analysis required to make sense of the large number of sections.

The combined use of transmission electron microscopy with computed tomography
(which has already been done by at least three different groups) should allow
analysis to a resolution of better than 100 angstroms.  Even the finest neurons
and dendrites are 1000 angstroms in diameter, so 100 angstrom resolution should
be adequate.

The concept of analyzing the human brain is being taken quite seriously in
the neuroscience community.  "Mapping the Brain and it's Functions" by
the Institute of Medicine, National Academy Press, 1991, discusses this.

In their "Summary of Recommendations" section, they say (among other things):
"The committee recommends that the Brain Mapping Initiative be established
with the long-term objective of developing three-dimensional computerized
maps and models of the structure, functions, connectivity, pharmacology, and
molecular biology of human, rat, and monkey brains across developmental stages
and reflecting both normal and disease states."

There were a number of further recommendations, calling (for example) for
international and cross-disciplinary cooperation in establishing and enlarging
the requisite data bases, establishing the needed funding, etc.

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=737