|From Douglas Fields' Perspective|
Myelination of layer II/III pyramidal neurons of the
cerebral cortex with a long axon initial segment and
segments with variable lengths of unmyelinated axon.
Yesterday we went to Cambridge to hear our younger grandson sing a solo part in Stanford's For Lo I Raise Up in his school concert. The stand-out performance was a string quartet led by a 15-year old called Patrick Bevan: really musical and someone to watch.
I've been meaning for a while to blog about the Tomassy et al. paper "Distinct Profiles of Myelin Distribution Along Single Axons of Pyramidal Neurons in the Neocortex" in Science. This strikes me as a very important paper in terms of making it clear, once more, that there is far more going on in the brain than the simplistic view of "Neurons + Synapses" suggests. As I'm fond of saying, the brain simply isn't a digital computer. It is analogue and asynchronous and enormously complicated, and what happens can depend on the exact details of pretty much any part of the brain or blood supply. As I explored in the book Questions of Truth (Appendix B) even in computer models like NEURON tiny timing differences get amplified up exponentially until they will make the difference between a neuron firing or not. This paper elucidates just some of the fascinating additional complexity that makes all attempts to recreate brains by digital means doomed to failure. This is not to say that such projects are without value - merely that they will not match the functioning of real brains.
So whilst I warmly applaud advances in Neuroscience (such as this, and the Allen Brain Atlas) it is ridiculously wrong to suppose that such things are "the first step to immortalizing the human biological soul." - to quote a comment post that is I think quite representative of much current thinking
PS I'm pleased to say that over 5 years after publication Questions of Truth is still in the top 100 on Science and Religion in Amazon.com.