Findings of a new research from Cornell University suggested that female rats display a stronger drive to socialize with other females after periods of intense isolation, significantly increasing the production of social calls similar to human emotional vocalizations. .
The researchers, whose study was published in PLOS ONE, said their behavior suggests a promising pathway for understanding the brain mechanisms through which isolation affects people’s social motivation and mental health – COVID-19. A growing concern during the -19 pandemic.
“This kind of social interaction among female rats is equivalent to our daily interactions with other people,” said Katherine Tschida, assistant professor of psychology in the College of Arts and Sciences.
“Intuitively, we know that social isolation has an effect on our behavior: We want to see and interact with people.”
The researchers set out to test whether exposure to acute isolation – alone in their home cage for three days – affected mice with so-called ultrasonic vocalization (USV), as well as non-vocal social behaviors such as sniffing and following another mouse. will be the reason. was presented in the cage. Inaudible to humans, Tschida said that the USV is neither speech nor language, but sounds such as laughing, crying and sighing that help indicate and communicate emotional states.
“It’s that kind of spontaneous, emotional type of vocal communication that we produce on top of our learned speech sounds,” Tschida said.
“By studying this in the mouse, we think we will gain insight into how this process is controlled in people as well.”
Female–female interactions showed a “profound effect” from acute isolation: a fourfold increase in USV compared to a control group of rats placed in group housing and more non-assertive social behavior.
“They interact a lot, they are too vocal,” Tschida said, “and the behavior of the subject animal—the lone mouse, essentially—seems to have changed.”
Scholars speculate that acute isolation may not be enough to significantly affect men’s sexual motivation with women or aggressive motivation with other men. But it does have a strong effect on women’s craving for associated social interaction thought to motivate social interaction. With a complicated caveat: After emerging from isolation, female rats climbed other females more frequently, possibly an expression of low-level aggression aimed at establishing a social hierarchy.
Tschida’s lab is now shifting from behavioral to neural studies of interactions between female rats. The researchers hope to identify the neurons that encode social context and emotional states in order to discover how isolation acts on circuits that control social motivation, including vocalization. In the long run, that knowledge may contribute to the understanding and treatment of disorders such as anxiety and depression, as well as factors that contribute to individual differences in susceptibility to social isolation.
“You feel lonely, you want to seek out social interaction – what exactly is causing it at the level of brain circuits?” Tschida said.
“Because we have its behavioral output end resolved, it becomes a more tractable question.”