A new research study from the Columbia University Medical Center, looked at brain tissue from the temporal lobe, or the area known to be involved in social behavior and communication, from 26 individuals with autism ages 2 to 20 as well as samples from 22 typically developing children, all of who died from other causes. Researchers were actually able to gain some new insight into how autism develops, why people with autism experience symptoms, such as over sensitivity to their environments, and what we can do to treat these symptoms.
As our brains develop it goes through what’s called a pruning process as we progress from child to adolescent to adult. This pruning process limits or turns off certain synapses, or connections, in the brain that allow neurons to communicate with one another. This is a natural and desirable process for typically developing brain, as an overactive brain that is constantly active and releasing too much of a particular neurotransmitter, such as serotonin, can lead to things like seizures—more than a third of people with autism experience epileptic seizures. Kids with autism, however, seem to actually retain this extra brain connectivity that typically developing children weed out as they grow older.
From the study they observed that the number of synapses was all around the same level in younger children from both groups but the adolescents had significantly fewer synapses than those with autism. David Sulzer, a professor of neurobiology at the Columbia University Medical Center who worked on the study, explains, “It’s the fist time that anyone had looked for and seen a lack of pruning during development of children with autism.” The typically developing 19 year olds had 41% fewer synapses than toddlers, but the ones with autism only had 16% fewer synapses. “Impairments that we see in autism seem to be partly due to different parts of the brain talking too much to each other. 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,” explains Ralph-Axel Muller, neuroscientist at San Diego State University.
This growing area of research in the field of autism is particularly promising as it provides new methods to treat autism, and researchers are hoping to do just that in the near future.