Turning on a set of neurons that dampen brain activity improves social behavior in a mouse model of were recently publishedin Science Translational Medicine.These findings help to add weight to the theory that autism could stem from too much excitation in the brain.

They’re also considering the future with the findings showing that treatments could restore the balance between excitation and inhibition, easing the social difficulties faced by people affected by autism. “If we could shift something in their brains in just the right way, we might be able to help them with social function,” says lead investigator Karl Deisseroth, professor of bioengineering and psychiatry at Stanford University in California.

The work relies on a technique called optogenetics that Deisseroth’s team pioneered. In this technique, researchers engineer mice to express light-sensitive proteins called opsins. They then shine light into the mice’s brains to turn certain neurons on or off.

Deisseroth’s team has used this technique to ease signs of anxiety, depression and obsessive-compulsive disorder in mice. This is the first time they have used optogenetics to manipulate social behavior in a mouse model of autism.

“I think this work is important because it provides the most direct evidence so far that acutely changing the ratio of excitation to inhibition immediately improves autistic-like behaviors,”says William Catterall, professor of pharmacology at the University of Washington in Seattle, who was not involved in the new study.

Practical application of the findings of the study is still some way off in the future. Every positive step forward is still a good sign for people living with autism.