“There must be some sort of classification to remember what is relevant and forget the rest,” Zugaro said. “We still need to understand how specific memories are selected for storage… Now we have a good clue.”
Last December, a research team led by Bendor at University College London published related results in Nature Communications that anticipated Yang and Buzsáki’s. They, too, found that sharp waves that were triggered When the rats were awake and asleep The researchers appeared to be labeling experiences in order to remember them. However, their analysis averaged a series of different trials, a less precise approach than the one achieved by Yang and Buzsáki.
The key innovation of the NYU team was to incorporate the temporal element, which distinguishes similar memories from one another, into their analysis. The mice ran through the same maze patterns, and yet the researchers were able to distinguish between blocks of trials at the neuronal level, a resolution never before achieved.
The brain patterns are marking “something a little bit closer to an event, and a little bit less like general knowledge,” he said. Loren Franka neuroscientist at the University of California, San Francisco, who was not involved in the research. “I think that’s a really interesting finding.”
“They are showing that the brain may be creating some kind of temporal code to distinguish between different memories that occur in the same place,” he said. Freyja Ólafsdóttira neuroscientist at Radboud University who was not involved in the work.
Shantanu JadhavBrandeis University neuroscientist praised the study. “It’s a good start,” he said. However, he hopes to see a follow-up experiment involving a behavioral test. Showing that an animal forgot or remembered particular test blocks would be “the real test that this is a labeling mechanism.”
The research leaves a burning question unanswered: why is one experience chosen over another? The new work suggests how the brain tags a particular experience for recall, but it can’t tell us how it decides what’s worth remembering.
Sometimes the things we remember seem random or irrelevant, and surely different from what we would select if we had the choice. “There is a sense that the brain prioritizes based on ‘importance,’” Frank said. Because studies have suggested that emotional or novel experiences tend to be remembered better, it’s possible that internal fluctuations in arousal or memory levels can play a role in the memory’s ability to remember. neuromodulators Like dopamine or adrenaline and other chemicals that affect neurons, they end up selecting experiences, he suggested.
Jadhav echoed that idea, saying, “The internal state of the organism may predispose experiences to be encoded and stored more effectively.” But it’s not known what makes one experience more likely to be stored than others, he added. And in the case of Yang and Buzsáki’s study, it’s not clear why a mouse would remember one experience better than another.
Buzsáki remains committed to exploring the roles sharp waves play in the hippocampus, though he and his team are also interested in the potential applications that could emerge from these observations. It’s possible, for example, that scientists could alter the waves as part of a treatment for conditions such as post-traumatic stress disorder, in which people remember certain experiences too vividly, he said. “The low-hanging fruit in this case is erasing the sharp waves and forgetting what you experienced.”
But for now, Buzsáki will continue to tune into these powerful brain waves to discover more about why we remember what we do.
Original story Reprinted with permission from Quanta Magazinean editorially independent publication of the Simons Foundation whose mission is to improve public understanding of science by covering advances and trends in research in mathematics, physical sciences, and life sciences.