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The brains of autistic children contain 67% more neurons
Medical expert of the article
Last reviewed: 01.07.2025
The prefrontal cortex of the brain, which is responsible for higher nervous functions, contains 67% more neurons in people with autism than in a normal person. This excess number of neurons prevents the brain from functioning normally and doing its job.
Back in 2003, American scientists (University of California, San Diego) discovered a peculiarity in the development of autistic children - during the first year after birth, these children's heads grew very quickly. Previously, scientists believed that such growth was associated with abnormal brain development, but what exactly happens to the brain of such children, researchers were able to determine only now.
Scientists analyzed the prefrontal cortex of the brain in seven children aged 2 to 16 who suffer from autism. The control group consisted of similar nerve tissue samples from healthy peers. The prefrontal cortex of the brain occupies about 1/3 of the entire gray matter and is responsible for performing almost all higher nervous functions: speech, cognitive functions, social behavior. Autism is characterized by a disorder of each of these functions.
The authors of the study found that the prefrontal cortex of the brain of autistic children has 67% more nerve cells than the brain of healthy children. Therefore, the brain of children with autism is heavier than the brain of healthy children, which is manifested by the enlargement of the skull after birth. New nerve cells of the cortex are formed during prenatal development, between the 10th and 20th week of pregnancy. According to the researchers, autistic children have a mechanism that blocks the destruction of extra neurons, which is launched before the birth of the child and continues for some time after birth. In healthy children, this mechanism is absent, due to which approximately half of the neurons are eliminated.
Excess neurons, and accordingly an excess of neural circuits, lead to disruption of the “information space”, which leads to inadequate performance of higher nervous functions.
This study shows that a large proportion of autism cases are associated with abnormalities in the child's embryonic development.