X-Message-Number: 19368 From: Date: Sat, 29 Jun 2002 10:16:10 EDT Subject: Brain reader, intensity interferometer --part1_125.12d73f3e.2a4f1b2a_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit I have already wrote a number of messages concerning the need for reading the contents of a brain in a nondestructive way. Indeed, it appears more and more that stem cells will make it possible to regenerate any body part. At least if one is only interested by the functional aspect. The case of the brain is separate: It must not only function, but set out again where it had stopped. It is of no use to start anew from zero and end up with a twin of the original person. In brain reading, two scales of analysis seem interesting: the one of connections between neurons and that of the molecular compexes of the synaptic buttons. The first is on the level of the micrometer, the second of a few tens of nanometers. The first is interesting for two reasons: It gives the wiring map of the brain and then the localization of the points of contact between neurons. This last element is useful for calculations necessary to reconstitute the brain, these calculations are considerable and the fact of being able to reduce the zone where they must be done is very significant. For that first scale, the magnetic imagery by raisonnance of helium 3 nuclei polarized per laser seems the solution (He3 NMR). The second scale of analysis, the finest, has more problems. The magnetic imagery by raisonnance would ask for months of recording, if not more. X-rays "dentists" (Photons of 60 keV) would do too many damage by radiations. The best solution seems to be the use of "soft" x-rays in an interferometer of the Michelson type with quantum nondemolition (QND). The probem is to get these x-rays with a very big coherence length, which implies a nuclear laser. I think that in approximately 30 years this device can be developed, either by exciting nuclei with entangled optical photons, or with devices of the thermonuclear type. Those can be quasi military: Theta pinch or compression by 2 stage guns and hollow-charges with hydrogen-xenon, or more exotic, quantum states carried out in a quantum calculator and teleported on the thermonuclear fuel (black magic). Another possibility, completely different would be to exploit an interferometer with particles, or interferometer with 2x2 waves. It would be then possible to exploit millimetric waves. This kind of device can extract information on a scale independent of the wavelength of radiation used, a millimeter-length wave can be thus used to look at objects 100 000 times smaller. In fact, even a device with two waves can do that if one takes into account the evanescent wave. The problem is then that of the proximity of the source. This soution is not valid for an image in 3 dimensions. To give some idea about a four wave interferometer, let us say that the interferometer with 2 waves produces interference fringes whereas the system with 4 waves counts correlations time in particle hits. In the interferometer with 4, or rather, 2 X 2 waves, what interferes are squares of amplitudes, therefore density of probability of presence of particles. When one integrates that over a defined time duration, one has a number of particles, for example a light intensity. Such intensities are thus compared. The key of the system is to have a rather fast recorder. By spreading out the beam of light over a CCD it is possible to have a high temporal resolution. If one sweeps 1000 times a second a mega pixels CCD, we are on the level of the nanosecond time resolution. I considered this system a few years ago, but such CCD were on the level of the laboratory at best. They are now in general consummer electronics products. In approximately 3 hours, it would be possible to obtain an image with a resolution of about 10 microns. To gain 3 orders of magnitude, it would take a time 1 milion time longer, that is to say nearly 500 years! One obviously needs larger sensors or more rapids systems. Each time one gains a factor 10 on the speed, one gains a factor 100 over the time of observation. For example by juxtaposing 10 CCD, with a sweeping 10 times faster, a brain can be analyzed in 5 years instead of 500. Theoretically, it is still possible to gain a factor 100 in speed, which would bring the complete analysis in a few hours. The current situation does not make it possible to build a brain reader, on the other hand, the technological development should produce the elements necessary some years from now. So, it seems desirable to establish a technology in this field, with intermediate interferometers which would make it possible to develop the software necessary to the rebuilding of the brain picture The original version of that text was in french, it was then translated by Alta-Vista Systrans one line service and combed a lot to remove the worst errors. Yvan Bozzonetti. --part1_125.12d73f3e.2a4f1b2a_boundary Content-Type: text/html; charset="US-ASCII" [ AUTOMATICALLY SKIPPING HTML ENCODING! ] Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=19368