Autism is a multi-faceted complex disorder. The cause is unknown, but most Scientist agree the brain plays a major role. Recent studies and much research has focused on the cerebral cortex, which is part of the brain responsible for language and social interaction, but Scientist believe there may be more to the story.
Scientists are discovering the cerebellum, which is the part of the brain that controls movement and motor development, may also play a part in attention and emotional regulation. “There’s an emerging body of data that the cerebellum is important for a lot more than regulating your motor movements. It regulates your emotions as well – your affective state – and your attention,” says William Dobyns, professor of genetic medicine at University of Washington in Seattle.
Last January in a published study, Dobyns and his team found that children who carried a deletion of an autism-linked chromosomal region, 22q13, were more likely to have a smaller than normal vermis, which connects the two halves of the cerebellum, an enlarged posterior fassia, the cavity the cerebellum sits within, or both. DNA analysis suggests that two genes in the 22q13 region, PLXNB2 and MAPK8IP2, are most closely linked to abnormalities of the cerebellum.
It was suggested in another study, published in July in PLoS Computational Biology, that cliques of autism-related genes may affect the cerebellum in mice. A group of 26 autism candidate genes that the team found had a tendency to be expressed together within the cerebellum.
A reduced number of Purkinje cells, which represent the main output of nerve signals from the cerebellum, with elaborately branching neuronal projections that travel to various regions of the cerebral cortex have consistently shown in Postmortem studies of autistic brains.
Emory University School of Medicine’s Chief of medical genetics Michael Gambello, found that mice lacking TSC2, an autism-related gene, in Purkinje cells showed social deficits related to autism. This replicated another study that showed removing TSC1, a related gene, from Purkinje cells also led to autistic behaviors in mice.
It was found in both studies that Purkinje cell degeneration occurred due to the loss of the gene, and that the drug rapamycin prevents Purkinje cell loss and the development of autism-like behaviors in mice by inhibiting a signaling pathway boosted by the two genes.
Charles Blaha, director of experimental psychology at the University of Memphis in Tennessee, conducted another study and found that stimulating the dentate nucleus part of the cerebellum results in the release of dopamine to the prefrontal cortex.
Blaha says “Not too many people have paid too much attention to dopamine and its relationship to autism.” He also points out that it is related to several cognitive functions, including, learning, memory, and theory of mind.
Studies are leading researchers to believe that the cerebellum plays a bigger role in autism than was previously suspected. “I think that there is very likely a percentage of children out there with autism where the cerebellum is playing a major role,” says Gambello.
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For more information on autism research, read here: http://www.icare4autism.org/what-is-autism/autism-research/