Contact: Kim Dalton or Richard Davidson <mailto:kmdalton@wisc.edu> kmdalton@wisc.edu
608-263 8913
Study: Eye contact triggers threat signals in autistic children's brains
MADISON - Brain tests at the University of Wisconsin-Madison suggest thatautistic children shy from eye contact because they perceive even the mostfamiliar face as an uncomfortable threat. The work deepens understanding of an autistic brain's function and may oneday inform new treatment approaches and augment how teachers interact withtheir autistic students. Tracking the correlation between eye movements and brain activity, theresearchers found that in autistic subjects, the amygdala - an emotioncenter in the brain associated with negative feelings - lights up to anabnormal extent during a direct gaze upon a non-threatening face. Writing inthe March 6 issue of the journal Nature Neuroscience, the scientists alsoreport that because autistic children avert eye contact, the brain'sfusiform region, which is critical for face perception, is less active thanit would be during a normally developing child's stare. "This is the very first published study that assesses how individuals withautism look at faces while simultaneously monitoring which of their brainareas are active," says lead author Kim Dalton, an assistant scientist atUW-Madison's Waisman Laboratory for Brain Imaging and Behavior. Daltonmeasured eye movements in conjunction with magnetic resonance imaging (MRI),a sophisticated technology that allows researchers to "see" a brain inaction. Notably, the UW-Madison study overturns the existing notion that autisticchildren struggle to process faces because of a malfunction in the fusiformarea. Rather, in autistic children the fusiform "is fundamentally normal"and shows only stunted activity because over-aroused amygdalas make autisticchildren want to look away, says senior author Richard Davidson, aUW-Madison psychiatry and psychology professor who has earned internationalrecognition for his work on the neural underpinnings of emotion. "Imagine walking through the world and interpreting every face that looks atyou as a threat, even the face of your own mother," Davidson adds.Scientists have in the past speculated that the amygdala - which has beenimplicated in certain anxiety and mood disorders - plays a role in autism,but the study directly supports that idea for the first time. An increasingly publicized developmental disability, autism greatly weakensthe capacity to socialize and communicate normally. The tendency to avoideye contact is one of the most pervasive traits among autistic children,says Dalton. The characteristic is a problem because eyes, in particular,are a crucial source of "subtle cues that are critical for normal social andemotional development," Dalton says. Dalton's work comprised two studies. In the first, researchers placedautistic children inside an MRI scanner and showed them pictures of faceswith both emotional and neutral expressions. The children had to press oneof two buttons to indicate whether a face showed a blank or expressive face.Throughout the process, the researchers used precise eye-tracking technologyto measure exactly which parts of the face study participants were lookingat and for how long. Normally developing children far outpaced the autisticstudy participants in identifying expressions correctly. During the second study, the researchers again placed subjects in MRImachines and showed them photographs of both familiar and unfamiliar faces.They monitored eye movements and brain activity, and once again, autisticsubjects performed considerably more poorly than normally developingparticipants. In the future, the findings could help scientists "train autistic childrento look at a person's eye region in a more strategic way, like when theperson may not be looking directly at them," says Davidson. Researcherseventually could assess whether such approaches improve the ability to makeeye contact and whether they might even induce positive developmentalchanges in the brain. Because autism is more inheritable than any other psychiatric condition,researchers also could start to explore the genetic mechanisms underlyinghyperactive amygdalas - "a completely uncharted research territory," saysDavidson. And if the autistic amygdala is found to be overactive frominfancy, the knowledge could help doctors implement intervention approachesright from an early age. ###
- Paroma Basu (608) 262-9772, <mailto:basu1@wisc.edu> basu1@wisc.edu
