Autism may be brain disorder, says children's study

Autism may be a disorder of hyper-connectivity in the brain, according to a study that found children with the condition have too many synapses, the points where neurons connect and communicate with each other.

The study, published Thursday in the journal Neuron, suggests that a dysfunction in the brain doesn't prune the neurons during development, as happens in most people. Researchers from NewYork-Presbyterian Hospital/Columbia University Medical Center examined tissue from the brains of children who had died, including those with and without autism.

Autism disorders are characterized by indifference to social engagement, communication difficulties and repetitive behaviors. There is no cure or single known cause, though studies have suggested a range of potential biological and environmental starting points.

"This is an important finding that could lead to a novel and much-needed therapeutic strategy for autism," Jeffrey Lieberman, psychiatrist-in-chief at the hospital, said in a statement. He wasn't involved in the study.

The researchers examined brain tissue from 26 children and adolescents ages 2 to 20 who had autism and from 22 more who didn't. The tissue was from a region of the brain involved in social and communication processes and implicated in autism. They counted the number of spines extended from the neurons, each of which connect with another neuron by synapse.

By late childhood, researchers found that spine density decreased by 41 percent in the normal brains, compared with 16 percent in the brains of autistic children. "This deficit may contribute to abnormalities in cognitive functions that humans acquire" later in development, the researchers wrote.