For anyone interested in life extension

I probably could have clarified: "N" stands for the number of lives you estimate this procedure could save above and beyond the "default". In other words, "Net future lives saved with body-transplant technology" minus "Net future lives saved without body-transplant technology"

An example would be, say that there are not any viable hosts for a cadaver's organs, so normally they would just have to cremate him which is +0 lives. But in this situation, they could transplant a head onto the body, which is +1 lives. And say that scenario plays out 50,000 times over the next however many years. So N=50,000.

Of course N will be much lower for you personally if you find that example (and other similar ones) unrealistic.

Don't know about the funding but the doctor is from Italy and is pretty well renowned.

http://www.surgicalneurologyint.com/article.asp?issn=2152-7806;year=2013;volume=4;issue=2;spage=335;epage=342;aulast=Canavero

It should be noted that this is not actually connecting neuron fibers. This is providing empty myelin sheath, with the nerve cells within dead and destroyed due to being cut off from their cell bodies. When the living ends of a cut nerve fiber on the end that contains the cell body are left undisturbed, a subset of them send out growth cones that wander out from the cut. If theres nothing there they dont do much but if a bunch of open ends of myelin sheaths are brought up next to them they will find sheaths and grow through them at something like a millimeter per day to the positions of the former nerve endings of the grafted nerve. You can string together multiple cut nerve fragments in fact, if a nerve is damaged in multiple places due to trauma.

The fibers are not going to grow to their original destinations, and your brain needs to relearn what the heck its controlling or feeling once the fibers grow the long distance through the nerve, but they can regrow and people can and do relearn how to use the remapped fibers. You can even transfer/remap which nerves control what within an individual: see http://nerve.wustl.edu/nd_transfer.php .

Notably, this happens automatically in the peripheral nervous system but usually not the central nervous system. All the attempts do do so in the spinal cord itself, a CNS tissue, have relied on weird interventions and are by no means reliably successful and have never involved tissue from two organisms to my knowledge.

Motor neuron fibers would need to grow from the brain down through the spine, and sensory fibers would need to grow from the spine up into the brain itself. That is not a process that I would expect to go nearly as well in an adult compared to during initial development.