University North Carolina. US: Tantrums, irritability, self-injury, depression, anxiety. These symptoms are associated
with autism, but they’re not considered core symptoms of the disorder.
Researchers from the UNC School of Medicine are challenging this
assertion. They have used functional MRI to show that – when it comes to
the ability to regulate emotions – brain activity in autistic people is
significantly different than brain activity in people without autism.
The findings, published online today in the Journal of Autism Developmental Disorder
as part of a special issue on emotion regulation, suggest that
improving prefrontal cortex activity could directly help autistic people
regulate their emotions and improve serious symptoms associated with
the disorder, which affects millions of people in the United States.
The discovery shows that “emotion regulation” symptoms have a
biological explanation that can be visualized using fMRI. The symptoms
do not seem to be merely associated with or a result of the core autism
symptoms, which include repetitive behaviors, verbal and non-verbal
communications problems, difficulties with social interactions, and
other cognitive issues.
Gabriel Dichter, PhD, associate professor of psychiatry and
psychology and senior author of the paper, said, “This research adds to
the growing awareness that although autism is diagnosed on the basis of
social impairment and repetitive behaviors, the importance of emotion
regulation and all the behaviors that come with it – depression,
tantrums, meltdowns, irritability – are very real and should be a focus
of clinical services.”
“Any parent of a child with autism knows that these symptoms can be
pervasive,” added Dichter, who is a member of the Carolina Institute for
Developmental Disabilities. “Children with autism often lack the
ability to cope with difficult emotional situations that result in
meltdowns and tantrums.”
There are only two FDA-approved medications to treat autism and
neither treats core symptoms; they treat high rates of irritability and
aggression. “We’ve known for a while that we need to pay attention to
emotion regulation in people with autism,” Dichter said, “but we think
these data suggest a neural basis for these problems and add credence to
their ubiquity as core features of the disorder.”
The Carolina Institute for Developmental Disabilities, directed by
Joseph Piven, MD, is the umbrella program for autism research at UNC,
which ranked second worldwide for the number of autism-related scientific papers published in 2012, the last time an intergovernmental agency issued the ranking.
The institute has a registry of more than 5,000 families with members who have been diagnosed with autism.
For this study, Dichter’s team recruited 15 controls and 15 young
adults, age 18 to 30, with autism. Because it is well documented that
people with autism often have trouble regulating their emotions,
Dichter’s team spent 45 minutes with each participant to teach them how
to change their perception of an emotional stimulus before they entered
the MRI scanner.
During the study, while in the fMRI scanner, each participant viewed a
series of pictures of human faces with no expression. Partway through
viewing each picture, participants were asked to generate positive
thoughts about the picture, or generate negative thoughts, or leave
their emotional response unchanged.
The researchers also used eye-tracking methods to ensure all
participants continuously viewed the picture and to measure at high
resolution the size of each participant’s pupils. It’s known that pupils
dilate when people exert cognitive effort, such as trying to recall
someone’s name or trying to change an emotional response to situation.
These methods, along with self-reporting from participants, created
checks and balances that ensured the accuracy of the data they collected
from brain scans.
They found that in the control group, the prefrontal cortex worked
hard to modulate the emotional response that originated in the limbic
system – an evolutionarily old part of the brain associated with basic
emotions and needs. This confirmed what other research had shown.
The brain scans of people with autism were different. “The prefrontal
cortex did not come online to the same extent,” Dichter said. “It was
as though the brain region that’s needed to work hard to regulate
emotional responses couldn’t activate to the same degree as it did in
people without autism. This limited activation of the prefrontal cortex,
not surprisingly, resulted in less modulation of the limbic regions.”
The pupil data suggested that participants worked hard to fulfill the
requirements of the study. They changed their emotional responses to
the picture. But their brain scans suggest that people with autism did
not use their prefrontal cortex to the same extent as people without
autism.
Thus, when faced with emotional situations, people with autism do not
use their prefrontal cortices to regulate emotions to the same extent
as people without autism. This in turn may lead to the “associated
symptoms,” such as anxiety, tantrums, and irritability, which can be
pervasive.
Dichter’s team also found a correlation between the level of brain
activity in the prefrontal cortex and the severity of a person’s autism.
“There does seem to be an association between the ability to bring
these brain regions online as needed during emotional situations and the
severity of a person’s autism symptoms,” Dichter said.
Next, Dichter wants to conduct a similar study with children.
“Studying children with autism helps us tease apart the effects of having autism from the affects of living with autism for years as a teenager and an adult.”
Future intervention research based on these findings could use
cognitive behavior techniques to improve emotion regulation abilities
for people with autism or brain stimulation techniques to improve
activity in the prefrontal cortex during emotion regulation.
The first author of the Journal of Autism Developmental Disorder
paper is John Richey, PhD, former postdoctoral fellow in Dichter’s lab
who was part of the T-32 training program at the Carolina Institute for
Developmental Disorders. He is now an assistant professor at Virginia
Tech. UNC graduate student Cara Damiano and former UNC graduate student
Anna Sabatino, are also authors.
The study was funded by the National Institute of Mental Health
and the Eunice Kennedy Shriver National Institute of Child Health and
Human Development. The study was also supported by the UNC-CH Graduate
School Dissertation Completion Fellowship and the Clinical Translational
Core of the Carolina Institute for Developmental Disabilities.
Dichter is also the director of UNC’s Clinical Affective Neuroscience Lab.