Scientists at the New York University (NYU) School of Medicine identified brain signals dubbed sharp wave ripples (SPW-Rs) that are believed to support working memory. Signals are created by brain cells (neurons). They become tens of milliseconds longer when a mammal is learning about a new place than when it is in a familiar environment.
https://blog.genexi.ru/news/Changing-Brain-Waves-Could-Improve-Memory-en