The reasons for such a long-standing bias in neuroscience are complicated, Datta said: “Part of it is just plain old sexism, and part of it is conservatism in the sense that people have studied male mice for so long that they don’t want to make a change.”
The team analyzed the videos with MoSeq, an artificial intelligence technology previously developed by the lab. The technology usesalgorithms to break down a mouse’s movements into around 50 different “syllables,” or components of body language: short, single motions such as rearing up, pausing, stepping, or turning. With MoSeq, the researchers gathered in-depth, high-resolution data about the structure and pattern of mouse behavior during each session.
“People have been making this assumption that we can use male mice to reliably make comparisons within and across experiments, but our data suggest that female mice are more stable in terms of behavior despite the fact that they have the estrous cycle,” Datta said.Scientists generally agree that including female mice is important from a fairness perspective, Datta noted, yet some have remained concerned that it could complicate their research.
Datta said that the findings “should encourage folks who are interested in drug development in this context to include both sexes in their analysis.” “I was shocked by how much stable variation between individuals we were observing — it’s like these mice really are individuals,” Datta said. “We’re used to thinking of lab mice as interchangeable widgets, but they’re not at all. So, what is controlling these individualized patterns of behavior?”