Why brain cells communication is so fast

Brain cells work like an organic supercomputer they keep everything going, from breathing to solving riddles. And now, researchers have for the first time described how nerve cells manage to transmit signals practically simultaneously.

The cells of the nervous system communicate using small molecule neurotransmitters such as dopamine, serotonin and noradrenalin.

Dopamine is associated with cognitive functions such as memory, serotonin with mood control, and noradrenaline with attention and arousal.

The brain cell communication network, the synapses, transmit messages via chemical neurotransmitters packaged in small containers (vesicles) waiting at the nerve ends of the synapses.

An electrical signal causes the containers and membrane to fuse and the neurotransmitters flow from the nerve ending to be captured by other nerve cells. This occurs with immense rapidity in a faction of a millisecond.

Researchers from the Universities of Copenhagen, Gottingen and Amsterdam have been studying the complex organic protein complexes that link vesicles and membrane prior to fusion, in order to find an explanation for the rapidity of these transmissions.

They have discovered that the vesicle contains no fewer than three copies of the linking bridge or "SNARE complex".

With only one SNARE complex the vesicle takes longer to fuse with the membrane and the neurotransmitter is therefore secreted more slowly.

“The precursors for the SNARE complexes are present in the vesicles before they reach the target membrane. Fast (synchronous) fusion is enabled when at least three of them work in tandem. If the vesicle only has one SNARE complex it can still fuse with the target membrane, but it takes much longer,” said Professor Jakob Balsev Sørensen from the Department of Neuroscience and Pharmacology at the University of Copenhagen.

The discovery has just been published in Science.