Tuesday, February 07, 2012

Our connectomes 'R Us?

I have received by now several offers from Houghton Mifflin publishers to send a reviewer's copy of Sebastian Seung's "Connectome: How the Brain's Wiring Makes Us Who We Are." I haven't acted on it, because a review of the synopsis has convinced me that Seung's own brilliant efforts, and similar works he describes to map every connection in our brain, are not the complete key to understanding ourselves that he implies. I was actually starting to write a list of problems I see with the idea that when you've got the wiring diagram between nerve cells you've got it all, but this succinct critique by Chris Koch permits me to be lazy:
Treating the connectome as the be-all and end-all of brain function has its problems. Seung, for example, rebrands autism and schizophrenia as 'connectopathies' — diseases in which the brain's wiring goes awry. Yet plenty of other things are wrong in brains with these disorders besides their connectivity.

Faults in synaptic transmission and in processes inside neurons and the glial cells that support them have all been implicated in mental illness and brain disease. Neurons are intricate devices with elaborate input structures that show complex, time-dependent and nonlinear processing. They have various characteristic, and often tortuous, morphologies. Connectionism treats all this as irrelevant. Even though we have known the connectome of the nematode worm for 25 years, we are far from reading its mind. We don't yet understand how its nerve cells work.

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