Researchers at the University of Washington have discovered an increased pattern of brain activity in the amygdalas of adults with autism that may be linked to the social deficits that typically are associated with the disorder.
Previous research at the UW and elsewhere has shown that abnormal growth patterns in the amygdala are commonly found among young children diagnosed with autism.
The amygdala is popularly associated with the "fight-or-flight response" in dangerous situations. But it has other functions, including identifying faces and situations and evaluating social information such as emotions.
The new research shows that brain activation in adults with autism remains elevated long after similar brain regions of typically developed adults have stopped being activated when exposed to a series of pictures of human faces. A decrease in activation over time to the same type of information is called neural habituation and is connected with learning, according to Natalia Kleinhans, lead author of the new study and a UW research assistant professor of radiology.
"What we are seeing is hyperexcitability or overarousal of the amygdala, which suggests that neurons in the amygdala are firing more than expected," said Kleinhans, who is associated with the UW Autism Center.
"If you consider that habituation reflects learning in as simple a task as looking at a face, slowness to habituate in people with autism may contribute even more markedly to difficulty with more complex social interactions and social cognition. If the brain is not reacting typically to a static face with a neutral expression, you can imagine how difficult it may be for someone with autism to pick up more subtle social cues."
The National Institute of Child Health and Human Development and the National Institute of Mental Health funded the research, which appears in the online edition of The American Journal of Psychiatry.
The UW researchers used functional magnetic resonance imaging to examine brain activation in 19 individuals with autism and in a comparison group of 20 healthy adults. The subjects ranged in age from 18 to 44 and the two groups were matched for IQs in the low-normal range. Both groups had their brains scanned while they looked at series of faces with neutral expressions. Each face appeared on a screen for three seconds and occasionally a face would be repeated two consecutive times. When that happened subjects were instructed to push a button.
The scientists were interested in what happened in two brain regions, the amygdala and the fusiform gyrus, when the subjects viewed the faces. It turned out that the fusiform gyrus, which helps determine what kind of object a person is looking at – a face or a house, for example – showed no habituation in either group. But the differences were striking when it came to the amygdala.
"The differences we found were in the amygdala and specific to the amygdala," said Kleinhans. "They originated there and did not go across the brain."
She said one theory about autism is that when this hyperarousal occurs an individual misses important information. Those individuals with autism who had the most social impairment exhibited the highest levels of amygdala arousal.
"This is another piece of evidence that there is something wrong with the amygdala in autism that contributes to social impairment. These results help refine our understanding of functional abnormalities in autism and are a new way of thinking about social dysfunction in autism," said Kleinhans.
Joel Schwarz | EurekAlert!
Further reports about: > Amygdala > Autism > Brain Activity > Health > almond-shaped structure > amygdala activity > brain activation > brain region > fight-or-flight response > functional abnormalities in autism > human face > neutral expressions > pictures of human faces > social cognition > social deficits in autism > social dysfunction in autism > social interaction
Cholesterol-lowering drugs may fight infectious disease
22.08.2017 | Duke University
Once invincible superbug squashed by 'superteam' of antibiotics
22.08.2017 | University at Buffalo
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
23.08.2017 | Materials Sciences
23.08.2017 | Automotive Engineering
23.08.2017 | Life Sciences