Mice certainly aren’t men, but they can teach us a lot about memories. And in the latest experiments, mice are helping to resolve a long-simmering debate about what happens to “lost” memories. Are they wiped out permanently, or are they still there, but just somehow out of reach?

Researchers in the lab of Susumu Tonegawa at the Picower Institute for Learning and Memory at MIT conducted a series of studies using the latest light-based brain tracking techniques to show that memories in certain forms of amnesia aren’t erased, but remain intact and potentially retrievable. Their findings, published Thursday in the journal Science, are based on experiments in mice, but they could have real implications for humans, too.

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The mice were trained to remember getting a shock in a certain chamber. The scientists then used protein labels to tag the specific cells in…