New research shows that children with autism have too many synapses or connections in their brains. A synapse acts a bridge between cells called neurons. The synapse is used to send information between the neurons. Having too many synapses results in poor communication between the cells and researchers think autism symptoms, such as sensitivity to sound, result from these communication problems.
As children grow, their brains prune or pare down the number of synapses. This research found a malfunction of this pruning process in children with autism. This malfunction leaves too many synapses in parts of the brain.
“Impairments that we see in autism seem to be partly due to different parts of the brain talking too much to each other,” said Ralph-Axel Müller, a neuroscientist at San Diego State University. “You need to lose connections in order to develop a fine-tuned system of brain networks, because if all parts of the brain talk to all parts of the brain, all you get is noise.”
Researchers able to remove extra brain connections in mice
In this study, researchers replicated autism symptoms in mice. Then, researchers were able to reduce the number of synapses in the mice by giving them a drug called rapamycin. The mice displayed less autistic behaviors after receiving rapamycin. Although researchers believe these findings are significant, they caution against expecting a treatment in the near future.
“The pruning problem seems to happen later in development than one might think,” Dr. Eric Klann, professor of neural science at New York University, said. “It suggests that if you could intervene in that process that it could be beneficial for social behavior.”
The study, "Loss of mTOR-Dependent Macroautophagy Causes Autistic-like Synaptic Pruning Deficits", is published in the journal Cell.