How do house hunters who visit 20 homes daily still recall details of the master bedroom of a specific one? Our memories can perform this neat trick because of the existence of modules of cells preformed based on prior experiences that can be triggered and recombined in the hippocampus to rapidly encode new experiences, suggests a new study by Yale researchers.
One theory has held that the cells in the hippocampus, a region of the brain crucial to forming new memories, fire in unique and novel rapid sequence as a person absorbs a new experience. This sequence is eventually consolidated as memory during sleep and by next day is cleared out of the hippocampus. This process is repeated for each new experience.
However, the new study suggests that hippocampal cells form modules that preserve past our experiences and contribute to new rapid learning, much as a “novelist doesn’t have to relearn the vocabulary before writing a new essay,” said George Dragoi, assistant professor of psychiatry and neuroscience and senior author of the study.
The modules help the brain retain a large capacity for organizing distinct events and still rapidly encode new memories, he said. The complex cellular coordination necessary for people to distinguish between many experiences is described on Aug. 23 in the journal Neuron. Download a PDF of the study.