Is anxiety related to autism, and where is it in the brain?

Anxiety is common in people with autism – but is is different than other types of anxiety or similar? Is it part of the autism phenotype? When does it start and what triggers it? Two new studies which use a longitudinal design and examine the links between autism features, anxiety symptoms and brain development are summarized this week. It shows that the amygdala is important, that some features of anxiety are core to ASD and some are separate, and it is related to autism features like insistence on sameness. This has implications for how anxiety is diagnosed and treated in those with ASD.

https://pubmed.ncbi.nlm.nih.gov/35871413/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9116934/?report=printable

How that little amygdala makes a big difference in autism

The amygdala has been shown to be differently sized in autistic people – at first it is too big then it becomes smaller than typically developing people. But how early are these differences seen and does it relate to a diagnosis? The Infant Brain Imaging Study tackled this question in a recent study which compared those who were likely to develop autism at 6 months to those with Fragile X to see if there were differences and if it was specific to autism. Their findings will surprise you and have implications for targeted supports and interventions.

https://pubmed.ncbi.nlm.nih.gov/35331012/

From cells to anxiety

Thanks to brain tissue research, scientists now know how cells in the amygdala form, connect, and how this changes with age.  But does that explain behavioral or neurological features in autism?  Last week, Dr. Inna Fishman from SDSU examined connections in and out of the amygdala in children and adolescents in autism, in a different study but the same age range as when cellular changes in the amygdala are seen.  Strikingly, the brain connections to regions outside the amygdala follow a similar pattern at a similar time, which may explain functioning, autism severity and anxiety in adolescents with autism.   Also this week, while autism is a spectrum, it’s on a spectrum with other neurodevelopmental disorders like ADHD.  Just like in autism, there are individuals who are not diagnosed with ADHD until adulthood.  But these adults show signs of autism as children.  This is similar to autism, where symptoms are there but may not manifest until later in life.

 

https://www.ncbi.nlm.nih.gov/pubmed/30274651

https://www.ncbi.nlm.nih.gov/pubmed/30338854

Here’s to understanding why people with autism have anxiety in adolescence

Using resources from the Autism BrainNet, researchers from UC Davis show specific brain changes in an area called the amygdala in autism.  The amygdala is associated with fear, emotion and anxiety in people with autism.  But because they can look at the brain directly,  the actual number of neurons in the amygdala can be counted not just in one individual, but in over 50 individuals across ages 2 to 50.  This remarkable study showed that too much activity in the amygdala early may lead to impaired function later on.  This could be caused by too many neurons which are present early on in life in people with ASD, and reflected by fewer neurons later on in life.  These difference can only be detected through looking directly at brain tissue.  To learn more, register for the Autism BrainNet at www.takesbrains.org/signup.

Here is a link to the paper:  http://www.pnas.org/content/early/2018/03/19/1801912115.long

Dr. Avino will be answering questions about this paper on a Q&A on April 9, 2018 – please register here:  https://register.gotowebinar.com/register/7051754498195523073

Post zygotic mutations in autism: what you need to know

Yes, another type of mutation in autism was revealed this week.  Those that are evident after the sperm and egg meet to form the zygote but still very early, during embryonic development.  Because it occurs after the original zygote is formed, the mutation is not found in every cell or every region of the body, called post-zygotic.  A collaboration of three major genetic consortia studied and collaborated on these types of mutations and revealed that they consist of about 7.5% of all de novo mutations in people with autism.  They affect autism risk genes and selectively target brain regions associated with autism.  Learn more about what this means for family planning and cognitive ability in people with autism.