Stress transmitted by other people brings a destructive effect to the brain. Researchers have discovered that it stimulates the development of serious mental illnesses such as anxiety and depressive disorders.
Recent studies prove that emotions and stress are indeed contagious. They missed investigating, however, if the receiver will eventually suffer from long-term consequences.
A team led by Jaideep Bains of the University of Calgary has filled this gap by studying pairs of mice comprised of a male and female rodent. One member of each pair was then taken to be exposed to mild stress before being returned to its partner.
Upon studying each pair's CRH neurons, which are responsible for controlling the animal's stress response, they found that brains of both the transmitter and receiver showed identical changes.
Researchers Use Optogenetics To Manipulate CRH Neurons
To observe the effects of this transmission further, the team altered CRH neurons through optogenetics so they can be controlled using light.
As these neurons were silenced, the transmitters remarkably experienced no stress at all, even with the introduction of triggers. Also, during its interaction with the receiver, there wasn't any transmission observed.
Alternatively, when researchers activated the neurons without the presence of triggers, both the transmitter and receiver experienced the same changes resulting from stressful conditions.
In a paper published Jan. 8 on Nature Neuroscience, they note that as CRH neurons were "turned on," the transmitter releases an "alarm pheromone" to alert the receiver, which in turn, alerts the other rodents.
Considering the similarities in the brain structure of mice and humans, this transmission observed during the experiment offers a deeper understanding as to how people form social networks.
"The ability to sense another's emotional state is a key part of creating and building social bonds," explains Bains in a report.
Between the genders, the team determined that females respond better to stress after interacting. The number of their CRH neurons was cut almost by half after spending some time with unstressed transmitters. Male rodents, meanwhile, did not exhibit the same character.
Psychological Stress Caused By Conflicts Affects Gut Bacteria
Moreover, another recent study by a team at Georgia State University uncovered evidence that social stress caused by conflicts alters the gut microbiota living in the digestive tract.
Having the ability to communicate with the brain, changes in these microorganisms then cause an increase in the production of stress hormones. Dr. Benoit Chassaing, one of the authors of the study, calls this process as "bi-directional communication."
In addition, the team found that repeated exposure to social conflict causes a bigger change in gut bacteria.