Nondestructive Uploading Procedures

Most proposed mind uploading procedures destroy the brain in the process -- slice by slice, layer by layer, or neuron by neuron. Such procedures suffer from two drawbacks: you only get one chance at the process, so if it fails you will be lost forever; and you can't make a "backup" copy of your brain while still in biological form. Nondestructive techniques would avoid both of these problems; these procedures somehow manage to scan the brain in its active, biological form without destroying it. (Actually, some techniques would require an inactive brain, but still not damage it; these avoid the first problem but not the second.)

A variety of nondestructive techniques have been proposed:

Gamma-Ray Holography, which uses a coherent gamma ray source to produce a three-dimensional recording of the brain structure with near-atomic resolution. The resulting information would then be interpreted by a computer to produce a functional reconstruction.
X-Ray Holography, which works in a similar manner but with different complications. X-Ray lasers are very difficult to produce even in theory (much more so than gamma-ray lasers); these proposals require more exotic means of producing coherent X-rays.
Unfortunately, both gamma rays and X-rays would have about 100 times the energy needed to vaporize whatever they hit, so this is not likely to be as nondestructive as it sounds.
MRI (Magnetic Resonance Imaging), a technique that uses a steep magnetic field gradient to cause atoms (usually hydrogen) in the brain to emit radio waves, which are collected and analyzed to produce a three-dimensional map of the distribution of those atoms. Currently MRI is used on live human subjects with a resolution of about 1 mm. Magnet technology will probably never permit sufficient resolution using protons. However, it has been suggested that Helium-3 would diffuse rapidly into cells and permit resolution sufficient for uploading. Also, MRI may be used in serial sections with great resolution (but that would not be a nondestructive technology).
Biphoton Interferometry, like holography, takes advantage of photon interference to recover information about the sample. It was suggested that the resolution does not depend upon the wavelength of light used. This is almost true in astronomy, where milliarcsecond resolution corresponds to several parsecs because the objects being imaged are so far away. In the brain, however, you want to resolve objects much smaller than that, and the wavelength does matter. The position uncertanty is the wavelength of your probe, and to get the resolution we require, we'd be right back to X-ray or gamma-rays, as above.
Correlation mapping, in which roughly 10^12 nanoscale probes are injected into the cerebrospinal fluid; each takes up residence in a random neuron and monitors its activity. At regular intervals, the probe secretes a chemical binary code which encodes the probe's serial number and the current state of its host cell. These codes are collected over an extended period of time, and the correlations between cell states are used to infer the functional connectivity of the brain. This is a very intriguing proposal, but needs more study to see whether it could actually work. See, for example, the paper described by Yamada et al. in [link dead] NEL Msg00152. Work by Randal Koene on rule extraction from neural networks appears to indicate that firing times would not be sufficient to reconstruct all the information in a neural network.

[Editor's note: these techniques (except for the last one) were taken from an article called "Uploading", by Yvan Bozzonetti, cryonics mailing list message # 3241, reprinted from Cryomsg #3212. Some of the refutations come from Robert Reid at the University of Toronto. Correlation mapping was proposed by Keith Lynch in Cryomsg #3326. Many thanks to these contributors.]

nondestructive.html . . . . . . . . 9/20/02 . . . . . . . Joe Strout