Cornell University:

When postdoctoral researcher Matthew Zipple releases lab mice into a large, enclosed field just off Cornell’s campus, something remarkable happens.

The mice, which have only ever lived in a cage a little larger than a shoebox, rear up on their back legs, sniff the air, move into the grass and begin to bound over it, a new way of moving and a totally new experience for them. It’s one of many they’ll have as “rewilded” mice, and in a new study, Cornell researchers have found that the novel environment changes the mice’s behavior and reverses anxiety, even when anxieties are well established.

In the study, published in Current Biology, researchers rewilded multiple cohorts of lab mice over two years and found that their fear response in a classic assay used to assess anxiety was reduced and even reversed after living in the field—even after a single week.

“We release the mice into these very large, enclosed fields where they can run around and touch grass and dirt for the first time in their lives,” said senior author Michael Sheehan, associate professor of neurobiology and behavior and a Nancy and Peter Meinig Family Investigator in the College of Agriculture and Life Sciences. “It’s a new approach to understanding more about how experiences shape subsequent responses to the world, and the hope is that what we learn from these mice will have more generalizability to other animals and to ourselves as well.” [Continue reading…]