Thursday, March 1, 2007

Mapping out a wiring diagram of the brain, one neuron at a time

An overwhelming undertaking, given there are millions of neurons in the brain, and "these circuits are difficult to unravel because dozens of different neuronal types are entangled within a precisely connected network, and even neighboring neurons of the same type differ in connectivity and function.".

The good news is, researchers at the Salk Institute have created a way to isolate one neuron, and then trace its interconnections and pathways.

""The bottom line is that you need two genes expressed in the cell or cell type of interest: TVA, to get the rabies virus in, and the missing viral gene so the virus can spread to connected cells," says Wickersham.
Experimenting on slices of neonatal rat brain, the Salk researchers inserted these two genes into selected neurons -- as well as a gene that fluoresces red when expressed. Then they applied the modified rabies virus, which had furthermore been given the ability to make infected cells fluoresce green. The result was spectacular: as expected, these red cells were selectively infected by the virus, which spread to hundreds of surrounding cells, turning them brilliantly fluorescent green."

Too bad they don't have a youtube video of this yet.

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