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Progress toward Cyberimmortality
the personality are encoded in the shape of the network of
connections linking neurons. “Self lives in the synapses,”
might be the motto of this viewpoint. Actually, much smaller
structures may also play a role, either inside the neurons or
on their surfaces near the synapses. It has even been suggested
that the glial cells, which outnumber neurons in the brain, are
not merely supportive tissue but have some active function in
thought or memory. Granting that further research is needed,
let us assume for present purposes that a mind really does
consist of the momentary structure of neuronal connections.
At present, we can only imagine how that fine structure might
be mapped.
Magnetic Resonance Imaging (MRI), Computer Assisted
Tomography (CAT scans), Positron Emission Tomography
(PET scans), Electroencephalography (EEGs or brain waves),
and infrared observation are non-destructive ways of studying
the brain. However, all of them have rather poor resolution.
For example, MRIs are generally unable to resolve features
smaller than a cubic millimeter, whereas thousands of neurons
may jostle each other within this space. To see smaller struc-
tures requires increasing the power of the MRI scan, but this
is dangerous and violates government regulations for research
on human subjects. Perhaps computer analysis techniques can
improve the resolution somewhat, but several of these meth-
ods already use sophisticated software, so we cannot count on
really dramatic advances without a fresh approach. [4]
Unfortunately, at the present time it is difficult to see how the
brain’s detailed structure could be mapped without destroy-
ing it. In the Visible Human Project of the National Library of
Medicine of the National Institutes of Health, two deceased
human beings were frozen and then sliced so that their cross
sections could be photographed, from head to toe. The images
were then computerized so that three-dimensional models
could be made of any of the organs. The resolution was at