Yale University scientists studied the brains of more than 500 people with and without autism of all ages. The youngest participants were six months old and the oldest fifty years old.
Subjects were placed under a brain scanner and by spread tensor photography (DTI) The white matter pathways in the brain were mapped. White matter pathways are extensions of neurons that allow cells to communicate with each other.
The US researchers saw differences in the white matter pathways of the autistic and non-autistic participants: there were fewer white matter pathways in the autistic people. These differences were particularly noticeable in the corpus callosum, the brain structure that connects the right and left hemispheres of the brain. The corpus callosum plays a role in many functions – including motor skills – although you can still function quite well without the skeleton. We know this because the corpus callosum was sometimes cut in people with severe epilepsy.
Differences were present in adults and adolescents, but not in younger participants. According to the scientists, this indicates that the abnormalities are caused by autism and not a significant cause.
Psychologist and neuroscientist Annabelle Nijhoff (Ghent University), found this discovery to be astonishing. It appears that decreased connections in the corpus callosum are indeed a consequence rather than the origin of autism. Although it may also have to do with individual differences, she says. Although it is fine for participants of different ages to participate, the researchers compared different subjects and did not follow the same group of people for a longer period of time. Furthermore, fewer adults participated and only one woman was among the 96 people.
Nejoff also says that the trial results are in line with current ideas about autism and the brain. It appears that there is not a single brain region implicated in autism, but rather larger networks that connect brain regions over longer distances. This includes the corpus callosum. In addition, some people with autism also have problems with their gross motor skills. We also know that people with autism usually have a hard time seeing the bigger picture and keeping an overview, but they are very good at remembering many details. This may have something to do with these types of abnormalities in larger brain networks.
The researchers hope the findings will lead to an early diagnosis of autism and lead to treatment options. Nejoff responds: “If these kinds of changes in the brain are really caused by autism and not a cause, it’s hard to make a diagnosis based on this at such a young age.” It is, of course, a starting point for further research into how these differences appear in the corpus callosum and whether there really are treatments that have an effect on them.
