0150 GMT December 16, 2019
The reason lies, among other things, in a small group of inhibitory nerve cells that can use the messenger GABA to curb the activity of other nerve cells. The neuroscientists at the University of Freiburg have discovered that the distances between communicating cells play a part in the regulation of brain networks, Physorg wrote.
GABA is released at special contact points, synapses, from a projection of the inhibitory cells that serves precisely this purpose, the axon. The messenger causes an electrical inhibitory current in the target cells. A special subtype of the GABA-releasing cells is the so-called basket cell. It is known to have a strongly inhibitory effect on brain circuits. A reason for this is the fact that basket cells have a long and widely branching axon, with which they can control hundreds to thousands of target cells scattered over a broad area.
Up to now, it was not clear whether all of these target cells are subject to the same inhibitory current or whether target cells that are more distant from the GABA-releasing basket cell are more difficult to keep under precise control.
With the help of the patch-clamp technique for measuring the inhibitory currents of individual cells, the team discovered that the farther away a target cell is, the smaller and longer are their inhibitory currents. In pharmacological and electrophysiological experiments and by means of detailed microscopic studies, the neuroscientists demonstrated that the basket cell axon with more distant target cells forms less synapses and that other proteins capable of sensing GABA are found in these synapses.