New findings challenge standard model of memory consolidation.
When we visit a friend or go to the beach, our brain stores a short–term memory of the experience in a part of the brain called the hippocampus. Those memories are later “consolidated” — that is, transferred to another part of the brain for longer–term storage. A new MIT study of the neural circuits that underlie this process reveals, for the first time, that memories are actually formed simultaneously in the hippocampus and the long–term storage location in the brain’s cortex. However, the long–term memories remain “silent” for about two weeks before reaching a mature state.

“This and other findings in this paper provide a comprehensive circuit mechanism for consolidation of memory,” says Susumu Tonegawa, the Picower Professor of Biology and Neuroscience, the director of the RIKEN–MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, and the study’s senior author.

The findings, which appeared in the journal Science on April 6, may force some revision of the dominant models of how memory consolidation occurs, the researchers say.

The paper’s lead authors are research scientist Takashi Kitamura, postdoc Sachie Ogawa, and graduate student Dheeraj Roy. Other authors are postdocs Teruhiro Okuyama and Mark Morrissey, technical associate Lillian Smith, and former postdoc Roger Redondo.