PROVIDENCE, R.I. -- Daily events are minted into memories in the hippocampus, one of the oldest parts of the brain. For long-term storage, scientists believe that memories move to the neocortex, or "new bark," the gray matter covering the hippocampus. This transfer process occurs during sleep, especially during deep, dreamless sleep.
Many neuroscientists have embraced and built upon this theory of memory storage, or consolidation, for a generation. But the theory is difficult to test. New research led by Brown University neuroscientist Mayank Mehta, conducted with Nobel Prize-winning physiologist Bert Sakmann, shows the best evidence yet of the sleep dialogue between the old brain and the new.
Their work, published in Nature Neuroscience, also shows that this interaction occurs in a startling way. Instead of the hippocampus uploading information to the neocortex in a burst of brain cell communication, Mehta found the opposite: the neocortex seems to drive the dialogue with the hippocampus.
The findings may give scientists a new understanding of how the brain manages memories in health and during dementia, offering up a fresh look at the causes of diseases such as Alzheimer's, as well as potential treatments.
"Long-term memory making may be a very different process than we previously thought," said Mehta, an assistant professor in the Department of Neuroscience at Brown. "Either this reversed dialogue is, somehow, a part of memory storage or this transfer of information from the old to the new brain may not occur during sleep. Either way, the results call into question commonly held theories about the role of cortico-hippocampal dialogue in sleep."
Edvard Moser, a professor at the Norwegian University of Science and Technology and director of the Centre for the Biology of Memory, is a leading expert on memory processes in the hippocampus. Moser said of the new research, "This technically sophisticated study may signific
Contact: Wendy Lawton