Friday, January 25, 2008


Wired reports on efforts to determine the brain's connectome, a comprehensive map of all the neural connections in the brain.
Lichtman's lab is creating what could be the equivalent of the genome sequencing machine, which dramatically sped up the race to map the human genome. It's an automated brain peeler and imager they call ATLUM.

ATLUM uses a lathe and specialized knife to create long, thin strips of brain cells that can be imaged by an electron microscope. Software will eventually montage the images, creating an ultrahigh-resolution 3-D reconstruction of the mouse brain, allowing scientists to see features only 50 nanometers across.

"It works like an apple peeler," Lichtman said. "Our machine takes a brain, peels off a surface layer, and puts it all on tape. These technologies will allow us to get to the finest resolution, where every single synapse is accounted for."

My predictions:

  • The number of projections from one region to another in the human brain will be under 2000. In other words, there will only be about 2000 genes that control the development of the fetal brain.

  • The mechanism by which local, short-range cortical connections is made will be the same everywhere. Any variations in morphology will result solely from the tasks that specific regions perform.

  • The cortex will turn out to be fairly boring. All the interesting stuff will be in how the cortex augments the processing of projections to and from the specialized structures in the brainstem.

  • We'll discover that autism and possibly schizophrenia are "connection diseases." In other words, autistic and schizophrenic individuals will have some very small number of missing or deformed connection pathways.

  • Projection anatomy will be fairly crude. The genomics will only influence the connectomics to the extent that projections to and from brain regions are approximate. All the heavy lifting will be done by learning and its consequent synaptic pruning.

  • When we understand how the connectomics is influenced by the genomics, we'll be able to engineer the same process in silicon. When we do that, we'll be able to engineer truly intelligent machines.

This is cool stuff, although I have to say that the idea of microtoming somebody's brain on a lathe sounds kinda yucky.

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