How Time Is Encoded in Memories

Rats and equations help researchers develop a theory of how our brains keep track of when events took place.

Written byCatherine Offord

| 19 min read

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No matter how he looked at the data, Albert Tsao couldn’t see a pattern. Over several weeks in 2007 and again in 2008, the 19-year-old undergrad trained rats to explore a small trial arena, chucking them pieces of tasty chocolate cereal by way of encouragement. He then recorded the activity of individual neurons in the animals’ brains as they scampered, one at a time, about that same arena. He hoped that the experiment would offer clues as to how the rats’ brains were forming memories, but “the data that it gave us was confusing,” he says. There wasn’t any obvious pattern to the animals’ neural output at all.

Then enrolled at Harvey Mudd College in California, Tsao was doing the project as part of a summer internship at the Kavli Institute for Systems Neuroscience in Norway, in a lab that focused on episodic memory—the type of ...

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Meet the Author

Catherine Offord
After undergraduate research with spiders at the University of Oxford and graduate research with ants at Princeton University, Catherine left arthropods and academia to become a science journalist. She has worked in various guises at The Scientist since 2016. As Senior Editor, she wrote articles for the online and print publications, and edited the magazine’s Notebook, Careers, and Bio Business sections. She reports on subjects ranging from cellular and molecular biology to research misconduct and science policy. Find more of her work at her website.
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