A Brown University research team, led by an Indian-American, has found that the electrical activity in the brain cells of sleeping mice isn't completely random.
The team observed a dialogue between the hippocampus and the neocortex, areas of the brain where memories are made and stored.
Mayank Mehta, Assistant Professor of neuro-science, led the research team that made the discovery.
The team's work was published in the Proceedings of the National Academy of Sciences.
"It's quite surprising," said Mehta, who has earned his doctoral degree in physics at the Indian Institute of Science, from where he moved to neuroscience and carried out postdoctoral training at several places, but most of his work was done at MIT.
"We've known for a century that the hippocampus and the neocortex are anatomically connected. But this is the first time we've seen the effect of this connectivity in the brains of live animals.
The dialogue is quite unexpected and complex, suggesting that this 'simple' brain circuit is much more sophisticated than we imagined," said Mehta.
"We've known for a century that the hippocampus and the neocortex are anatomically connected. But this is the first time we've seen the effect of this connectivity in the brains of live animals," he said in a University news release.
"The dialogue is quite unexpected and complex, suggesting that this 'simple' brain circuit is much more sophisticated than we imagined."
The researchers discovered that the slow and regular firing of excitatory cells in the neocortex was echoed in three parts of the hippocampus, suggesting that the neocortex initiates and controls the communication instead of the hippocampus, according to the release.
Mehta suggested, in a commentary published in the Nature Neuroscience journal in January, that memories are not stored during sleep but instead that sleep acts as a way to erase memories and create "a fresh page" for new memories, according to the release.
"All of this research raises more questions than it answers," Mehta said. "But we do know this: How we make and store memories is a more complex process than we thought." Mehta's work was supported by the Rhode Island Foundation, the Salomon Foundation, NARSAD: the Mental Health Research Association, the National Institutes of Health and the National Science Foundation.
