The human connectome

We had the human genome project, and now we have the human connectome project. In this week's New Scientist there is a short article entitled Connectome. I found an on-line paper entitled The Human Connectome: A Structural Description of the Human Brain whose abstract reads:

The connection matrix of the human brain (the human “connectome”) represents an indispensable foundation for basic and applied neurobiological research. However, the network of anatomical connections linking the neuronal elements of the human brain is still largely unknown. While some databases or collations of large-scale anatomical connection patterns exist for other mammalian species, there is currently no connection matrix of the human brain, nor is there a coordinated research effort to collect, archive, and disseminate this important information. We propose a research strategy to achieve this goal, and discuss its potential impact.

This project is much more realistic in its scope than the ridiculously premature Mission to build a simulated brain that I wrote about a while ago. Measuring the connection matrix of the human brain might seem to be mundane and rather like butterfly collecting, but it is essential to collect lots of data in order to constrain the imagination of the scientists who construct models of the brain; without such data we would not be doing science.

I wish them well in the success of this project. However, knowing the connection matrix does not imply that you understand the brain states that emerge from the corresponding network of neurons. It is not even clear that the connection matrix is a sufficient description of the network of interconnections between neurons. Even if you know the connection matrix, it does not tell you anything about the self-organisation of such a network of connections in the first place. Which aspects are genetically determined and which are the result of being driven by sensory inputs?

Are there as yet undiscovered universal principles governing such self-organisation? I'll bet there are.