Brain 'noise' found to nurture synapses
A long-overlooked form of neuron-to-neuron communication called “miniature neurotransmission” plays an essential role in the development of synapses, a study by researchers at Columbia University Medical Center has shown. The findings raise the possibility that abnormalities in miniature neurotransmission may contribute to neurodevelopmental diseases.
The primary way in which neurons communicate with each another is through “evoked neurotransmission.” This process begins when an electrical signal, or action potential, is transmitted along a long, cable-like extension of the neuron called an axon. Upon reaching the axon’s terminus, the signal triggers the release of chemicals called neurotransmitters across the synapse.
Finally, the neurotransmitters bind to and activate receptors of the neuron on the other side of the synapse. Neurotransmitters are packaged together into vesicles, which are released by the hundreds, if not thousands, with each action potential.
Evoked neurotransmission was first characterized in the 1950s by Sir Bernard Katz and two other researchers, who were awarded the 1970 Nobel Prize in Physiology or Medicine for their efforts.
“Dr. Katz also found that even without action potentials, lone vesicles are released now and then at the synapse,” said study leader Brian D. McCabe, PhD, assistant professor of pathology and cell biology and of neuroscience in the Motor Neuron Center.
“These miniature events, or minis, have been found at every type of synapse that has been studied. However, since minis don’t induce neurons to fire, people assumed they were inconsequential, just background noise.”