Brain Policing

A Rare Nerve Cell Keeps a Tab

Scientists from the Karolinska Institutet and the Brain Mind Institute in Switzerland have discovered a cell which triggers off signals that maintain the balance between excitatory and inhibitory activity in neuron cells. The cells are known as martinotti cells. The study was reported in the journal Neuron.

The cell prevents diseases like epilepsy, schizophrenia and anxiety, they said.

The human brain consists of around a hundred million nerve cells linked together by around ten billion contact junctions called synapses.

The activity of this extremely complex network is regulated through a dynamic balance between excitatory signals, which are transmitted by one type of synapse, and inhibitory counter-signals, which are transmitted by another.

Excitatory signals are much more than the inhibitory signals. But the numerous martinotti cells act as a safety device, which sends inhibitory signals as soon as they receive signals above a certain frequency, according to the study.

The martinotti cells link collections of pyramid cells. The inhibitory signals that these cells generate prevent the pyramid cells, the most common neurons in the brain, from being over-activated, the study said.

"A characteristic feature of epilepsy is the hyper-activation of cortical pyramid cells, which is exactly what this mechanism inhibits. It is possible that epilepsy is related to a deficit of martinotti cells or a deficiency of martinotti activity in the brain," said Gilad Silberberg, one of the researchers of the study.

Source: Invention Intelligence, April 2007