Master switch that "balances the brain" found.

This is huge. It could have major effect on studies into epilepsy, schizophrenia, autism, being a Yankees fan, you name it. From Science Daily:

Neuroscientists at Children's Hospital Boston have identified the first known "master switch" in brain cells to orchestrate the formation and maintenance of inhibitory synapses, essential for proper brain function. The factor, called Npas4, regulates more than 200 genes that act in various ways to calm down over-excited cells, restoring a balance that is thought to go askew in some neurologic disorders.

Synapses, the connections between brain cells, can be excitatory or inhibitory in nature. At birth, the rapidly developing brain teems with excitatory synapses, which tend to make nerve cells "fire" and stimulate their neighbors. But if the excitation isn't eventually balanced, it can lead to epilepsy, and diseases like autism and schizophrenia have been associated with an imbalance of excitation and inhibition. The creation of inhibitory connections is also necessary to launch critical periods -- windows of rapid learning during early childhood and adolescence, when the brain is very "plastic" and able to rewire itself.

Npas4 is a transcription factor, a switch that activates or represses other genes. The researchers, led by Michael Greenberg, PhD, director of the Neurobiology Program at Children's, demonstrated that the activity of as many as 270 genes changes when Npas4 activity is blocked in a cell, and that Npas4 activation is associated with an increased number of inhibitory synapses on the cell's surface.