"You can think of the inhibitory modulation as a system of control for ensembles of neurons, both in spatial and temporal terms. It's a system that must depend upon a very stringent genetic program we can assume this is true since the outcome is almost always right. But we also know how important the proper 'tuning' must be, based on our observations of neuropsychiatric and other brain illnesses. If the system is not in balance, you can have major illnesses such as schizophrenia or autism or epilepsy."
While the main purpose of the work just published was to create a resource for neuroscientists, the Huang lab's first experiments with newly engineered mouse lines have enabled them to see things never before seen. In one experiment, the CSHL team has been able to track the migration of GABA neurons from the site of their "birth" in a structure called the MGE (medial ganglionic eminence), along a route that takes them to specific spots within the cortex. "It's fascinating," says Huang. "They are generated far outside the cortex to make an analogy, it's as if they were born in Africa and take various but very specific routes to another continent. Once you track them, as we have, you can see these paths are not random; they are like highways."
More generally, says Huang, "Not only can we now watch specific inhibitory cell types from early in development; we can also watch as they migrate and establish connections, grow dendrites, make synapses. I would argue this 'Gene-based cell Positioning System' is even better than GPS, because it allows us to track how the circuits actually assem
|Contact: Peter Tarr|
Cold Spring Harbor Laboratory