Mice with "mohawks" could help researchers gain insight into autism.
A research team noticed a group of mice genetically engineered to possess an autism gene had "overgroomed hair," an NYU Langone Medical Center news release reported. Mice usually groom each others fur.
Overgrooming is a "repetitive motor behavior," which could be a sign of autism. The finding marks the first time this type of behavior has been linked to a specific biological pathway. The research also suggests these "pathways" are reversible.
In the study the research team looked at a protein in mice called Cntnap4, which is specialized in certain brain cells (interneurons) in people with autism.
The team found that eliminating Cntnap4 affected GABA and dopamine, two essential chemical messengers in the brain.
GABA helps control impulses and regulate muscle tone while dopamine produces pleasant and soothing sensations. Repressing Cntnap4 led to a reduction in GABA and an increase in dopamine activity.
"Our study tells us that to design better tools for treating a disease like autism, you have to get to the underlying genetic roots of its dysfunctional behaviors, whether it is overgrooming in mice or repetitive motor behaviors in humans," senior study investigator Gordon Fishell, PhD, the Julius Raynes Professor of Neuroscience and Physiology at NYU Langone, said in the news release. "There have been many candidate genes implicated in contributing to autism, but animal and human studies to identify their action have so far not led to any therapies. Our research suggests that reversing the disease's effects in signaling pathways like GABA and dopamine are potential treatment options."
The team found that Cntnap4 in mature interneurons strengthened the GABA signal, but the same was not true in younger interneurons.
Researchers exposed young mice with normal Cntnap4 levels who did not groom each other to to more mature mice without Cntnap4. Only the mature mice without Cntnap4. carefully groomed the hairstyles of the other mice.
In the future the team hopes to look at how GABA and dopamine production evolves as the brain cells mature.