The gateways of communication between neurons in the brain are known as synapses, and these can be either excitatory or inhibitory. An excitatory synapse will stimulate the neighbouring neuron to 'fire', whilst an inhibitory synapse will have the opposite effect. When a child is born, there is an abundance of excitatory synapses in its brain, which must later be balanced by inhibitory synapses in order for the baby to develop normally. If the excitatory synapses remain unopposed, the neurons of the brain become overactive, which can lead to seizures or other neurological problems.

A molecule in the brain known as Npas4 has control over many genes, and is responsible for either activating or suppressing them. Researchers in Boston, USA recently, studied the precise function of Npas4, by experimentally blocking and stimulating its activity in neurons, and examining the resulting effects.

They discovered that Npas4 is stimulated by excitatory synaptic activity, and that once it is activated, an increased number of inhibitory synapses appear on the neurons. In light of this, it is likely that the excitatory environment of a new born brain stimulates Npas4 activity, and that Npas4 then increases the number of inhibitory synapses in the area, providing the necessary balance between excitation and inhibition.

Npas4 is therefore a potentially important factor in the development of epilepsy, because if its function is blocked for some reason, the neurons of the brain will become hyperexcitable.

Evidence to support this came when the scientists examined mouse models that had been bred to lack Npas4. These mice were anxious and prone to seizures.

Finally, the researchers found that when Npas4 activity was blocked, as many as 270 genes were affected. This suggests that Npas4 plays an extremely important role in the development and maintenance of a healthy brain.

The next steps will be to identify all 270 genes that are controlled by Npas4, examine the precise effects upon these genes that abnormal Npas4 function will have, and clarify how abnormal Npas4 can lead to different neurological disorders.

The findings of this study are extremely exciting, because they suggest that Npas4 is essentially a switch that, if faulty, can lead to a number of conditions including epilepsy. Once more research has been performed, a drug that targets Npas4, and treats a spectrum of neurological disorders, could potentially be developed in the future.

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