Scientists Discover Neurons that Control How Social You Are: New Findings for Autism

Children and adults with autism can often be less social. In fact, they often display an increased tendency to engage in solitary behaviors. Now, scientists have discovered antagonistic neuron populations in a mouse's amygdala, a segment of its brain, that actually controls social behaviors.

"We know that there is some hierarchy of behaviors, and they interact with each other because the animal can't exhibit both social and asocial behaviors at the same time," said David Anderson, one of the researchers, in a news release. "In this study, we wanted to figure out how the brain does that."

More specifically, the scientists found two intermingled populations of neurons in the amygdala, a part of the brain that is involved in innate social behaviors. While one population of these neurons promotes social behaviors, such as mating, fighting and social grooming, the other population promotes repetitive self-grooming, which is an asocial behavior.

In order to examine the relationship between these two populations, the scientists used a method called optogenetics. This is a technique that involves genetically altering neurons so that they express light-sensitive proteins from microbial organisms. By shining a light on these neurons, the researchers can then control the activity of the cells and their behaviors.

The researchers found that with the two populations of neurons appeared to interfere with each other's function. For example, the activation of social neurons inhibited the self-grooming behavior while the activation of self-grooming neurons inhibited social behaviors. Now named the seesaw circuit, researchers believe that these findings could have relevance to human behavioral disorders, such as autism.

"In autism, there is a decrease in social interactions, and there is often an increase in repetitive, sometimes asocial or self-oriented behaviors," said Anderson. "Here, by stimulating a particular set of neurons, we are both inhibiting social interactions and promoting these perserverative persistent behaviors."

The findings reveal a bit more about both social and asocial behaviors. This, in turn, could allow scientists to develop treatments for behavioral disorders, such as autism.

The findings are published in the journal Cell.