Poster Session C, Sunday, March 24, 5:00 – 7:00 pm, Pacific Concourse
Individuals with autism exhibit atypical pupillary responses under cognitive load
Michael C. Granovetter1,2, Charlie S. Burlingham3, David J. Heeger3, Marlene Behrmann1; 1Carnegie Mellon University, 2University of Pittsburgh, 3New York University
One proposal for a neural mechanism underlying features of autism spectrum disorders (ASD) is that there is a disruption in the homeostasis of cortical excitation and inhibition. Norepinephrine is a global modulator of the balance of excitatory and inhibitory neural activity and is critical for regulating an array of cognitive processes. Using pupillometry—a non-invasive technique for inferring cortical norepinephrine release—we investigated whether individuals with ASD exhibit inherent differences in pupillary responses, relative to typical individuals, in the context of a one-back working memory task. 16 adults with autism and 16 neurotypical age-matched controls performed a one-back letter detection task while pupil size was continuously measured at a rate of 1000 Hz. There were no significant differences in the number of correct responses to repeated letters between individuals with ASD and controls. However, there were between-group differences in the impulse response function (IRF) of pupil dilation during correct responses: a support vector machine, trained iteratively with a random subset of individual participants’ IRFs, revealed above chance accuracy in classification of group (autism, typical) on data from left-out participants. These findings indicate that even on a task in which behavioral performance by ASD individuals is comparable to that of neurotypical controls, there are nonetheless group differences in pupil responses. This suggests that cortical norepinephrine (and potentially acetylcholine) is modulated differently in individuals with ASD.
Topic Area: EXECUTIVE PROCESSES: Working memory