Emotional Contagion: Other People's Stress Can Change Your Brain

Next, the team used optogenetic approaches to engineer these neurons so that they could either turn them on or off with light. When the team silenced these neurons during stress, they prevented changes in the brain that would normally take place after stress. When they silenced the neurons in the partner during its interaction with a stressed individual, the stress did not transfer to the partner. Remarkably, when they activated these neurons using light in one mouse, even in the absence of stress, the brain of the mouse receiving light and that of the partner were changed just as they would be after a real stress.

The team discovered that the activation of these CRH neurons causes the release of a chemical signal, an ‘alarm pheromone’, from the mouse that alerts the partner. The partner who detects the signal can in turn alert additional members of the group. This propagation of stress signals reveals a key mechanism for transmission of information that may be critical in the formation of social networks in various species.

Another advantage of social networks is their ability to buffer the effects of adverse events. The Bains team also found evidence for buffering of stress, but this was selective. They noticed that in females the residual effects of stress on CRH neurons were cut almost in half following time with unstressed partners. The same was not true for males.

Bains suggests that these findings may also be present in humans. “We readily communicate our stress to others, sometimes without even knowing it. There is even evidence that some symptoms of stress can persist in family and loved ones of individuals who suffer from PTSD. On the flip side, the ability to sense another’s emotional state is a key part of creating and building social bonds.”

This research from the Bains lab indicates that stress and social interactions are intricately linked. The consequences of these interactions can be long-lasting and may influence behaviours at a later time.

In addition to Sterley and Bains, the paper’s other authors are Dinara Baimoukhametova, Tamás Füzesi, Agnieszka Zurek, Nuria Daviu, Neilen Rasiah and David Rosenegger.

The study was made possible through the generous contribution of longtime HBI donor Mr. Sanders Lee.

The research was supported by several funding sources including the Canadian Institutes for Health Research, Brain Canada, and Alberta Innovates.

Cumming School of Medicine’s Hotchkiss Brain Institute (HBI),

University of Calgary