Beta-adrenergic modulation of context porcessing in autism spectrum disorders

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Previous studies have shown improvements in cognitive flexibility and verbal problem solving following administration of propranolol, a beta adrenergic antagonist, to individuals with autism spectrum disorders (ASD). The observed effect is presumed to be related to the adrenergic projections to the prefrontal cortex and related brain regions. It remains unclear to what extent this benefit may extend to other aspects of executive control. The present study examines the potential effect of propranolol on context processing in individuals with and without an ASD. Fourteen high functioning adults with an ASD and a demographically-matched comparison group of 13 typically developing individuals participated. An AX continuous performance test (AX-CPT) was used to evaluate the contributions of working memory and inhibitory control to context processing. AX-CPT performance was assessed once following propranolol and once following placebo administration, in a counterbalanced manner. Overall the groups displayed comparable inhibitory control performance. In contrast, individuals with ASD made more errors in the working memory condition. Importantly, administration of propranolol was associated with improvements in working memory for the ASD group but had no effect on performance in the control group. Other aspects of task performance (e.g., inhibitory control) were unaffected. The present findings suggest that pharmacological treatment with propranolol may help individuals with ASD to overcome difficulties with executive control and context processing. Additional research is needed to better understand the neurophysiological mechanisms underlying this observed effect.