Objectives: To determine whether the central acetylcholinesterase (AChE) activity, a marker for the cholinergic system, is altered in ASD, and the alteration in the AChE activity, if any, is correlated with their social functioning.
Methods: Twenty adult subjects with ASD (14 male and 6 female; age range 18-33 years; mean [SD] IQ, 91.6 [4.3]) and 20 age-, sex-, and IQ-matched healthy comparison subjects were recruited from the community. Using positron emission tomography and a radiotracer N-[11C]methyl-4-piperidyl acetate ([11C]MP4A), regional cerebrocortical AChE activities were estimated by reference tissue-based linear least-squares analysis and were expressed in terms of the rate constant k3. Current and childhood autistic symptoms in the adult subjects with ASD were assessed by the Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R), respectively. Voxel-based analyses as well as region-of-interest (ROI)-based methods were used for between-subject analysis and within-subject correlation analysis with respect to clinical variables.
Results: Both voxel- and ROI-based analyses revealed significantly lower [11C]MP4A k3 values in the bilateral fusiform gyri in subjects with ASD than in those of controls (P < .05, corrected). The fusiform k3 values in subjects with ASD were negatively correlated with their social disabilities as assessed by ADOS as well as ADI-R.
Conclusions: The results suggest that a deficit in cholinergic innervations of the fusiform gyrus, which can be observed in adults with ASD, may be related with not only current but also childhood impairment of social functioning.
See more of: 4th Oral Brain Imaging in ASD temporary
See more of: Brain Structure & Function