For my money, what was simultaneously the most exciting and depressing part of the Dawn of the Neurohacking Revolution was the discovery that the immune system contains specific instructions that prevent it from regenerating neurons, and that the instructions can be disabled.
Exciting: You take a pill and your spinal cord regrows. That's not an
"advance", that's Star Trek. That's Dr. McCoy walking through the halls
of an Earth hospital in "STIV: The Voyage Home".
Depressing: If you try to regenerate neurons, you'll probably destroy the programming - there's almost certainly a reason why the immune system is deliberately refusing to repair neurons.
-- email@example.com Eliezer S. Yudkowsky http://pobox.com/~sentience/AI_design.temp.html http://pobox.com/~sentience/singul_arity.html Disclaimer: Unless otherwise specified, I'm not telling you everything I think I know.