The areas that glow particularly in this cross-section of the mouse brain are decisive for how social the animals are. When these circuits are stimulated, the mice practice social distancing – they avoid company.
We humans are social beings like mice – we need contact with conspecifics. How strong this tendency towards sociability is, however, can vary greatly from person to person. Some people love to get to know as many new people as possible and prefer to surround themselves with many friends and acquaintances. Others, on the other hand, have a rather small group of friends and are also very good on their own. An extreme case is people with autism – their social interactions are often severely disrupted.
So far, it is only partially understood whether these differences are also manifested in the brain and where the areas and circuits are located that control our need for social proximity and contact. But now an experiment with mice has given new insights. For this purpose, researchers at the Scripps Research Institute in La Jolla, California, manipulated certain areas in the brain of mice in such a way that they were able to switch these neurons on and off in a targeted manner.
This enabled the scientists to identify two neural circuits that decisively influenced the social behavior of the mice. Depending on whether the centers were active or inactive, the animals either sought to be close to fellow species or avoided them. Both circuits connect areas of the cerebral cortex to the amygdala, a part of the brain responsible for emotions and fear.
This photo shows a cross section through a mouse brain, in which the different areas and layers of the brain tissue are colored. The brightly lit areas mark the line of the brain that is involved in the decision between approach and “social distancing”.