Biomedical engineering researchers at Case Western Reserve University have identified a previously unidentified form of neural communication, a discovery that could help scientists better understand the neural activity surrounding brain processes and specific brain disorders.
"We do not know yet the part" And what? "From this discovery," said Dominique Durand, Principal Investigator, Professor Elmer Lincoln Lindseth in Biomedical Engineering and Director of the Center for Neural Engineering at the Case School of Engineering. "But we know that this seems to be a whole new form of communication in the brain, so we're very excited about it.
Until now, neurons "spoke" in the brain in three known ways: via synaptic transmission, axonal transmission, and what are called "gap junctions" between neurons.
Scientists have also learned, however, that when multiple neurons are activated together, they generate weak electric fields that can be recorded with the electroencephalogram (EEG). But these fields were too small to contribute to neuronal activity.
These new experiments in Durand's laboratory have shown, however, that not only can these fields excite the cells, but they can also produce their own electric fields and generate a wave of self-propagating activity.
This newly discovered form of communication was discovered while Case Western Reserve scientists were analyzing the relatively fast brainwave propagation mechanism similar to that generated during our sleep. They call this ephaptic (or electrical) coupling, a reference to the low-level electrical field known and observed in the brain – but it is now thought that it is also capable of generating neural activity.
"We have known these waves for a long time, but nobody knows their exact function and no one thought that they could spread spontaneously," Durand said. "It's been 40 years since I studied the hippocampus, which is only a small part of the brain, and this constantly surprises me."
This surprise culminated in a series of experiments during which Durand and his team observed a "jump" wave through a break that they had made in cutting the fabric. cerebral – a phenomenon that they conclude could only be explained by the coupling of the electric field.
Again and again, the brainwave seemed to jump over the void. Imagine a "wave" of stadium admirers hitting the empty stands in the center-field. You expect the wave to disintegrate, but it is again captured by the crowd in the right field and continues to cross the crowd.
Except that it was the behavior of waves in neural tissue that had never been reported before by neuroscientists, nor by anyone, the scientists said.
Durand said he did not believe it when he saw it. Neither fellow researchers in his laboratory nor a partner of Tianjin University in China.
"It was a staggering moment," he said, "for us and for all the scientists we've talked to so far."
Among the doubtful ones: The Journal of Physiology Review Committee, which asked Case Western Reserve researchers to conduct additional experiments to double-check their work before agreeing to the publication of the work.
"But all the experiments we've done since to verify it have confirmed so far," Durand said.
This article has been republished from material provided by Case Western Reserve University. Note: Content may have changed for length and content. For more information, please contact the cited source.
Chiang, C., Shivacharan, R., Wei, X., Gonzalez-Reyes, L. and Durand, D. (2018). A slow periodic activity in the longitudinal section of the hippocampus can be propagated non-synaptically by a mechanism compatible with ephaptic coupling. The Journal of Physiology, 597 (1), pp. 249-269.