Atypical Learning in Autism Spectrum Disorders: A Functional Magnetic Resonance Imaging Study of Transitive Inference.
OBJECTIVE
To investigate the neural mechanisms underlying impairments in generalizing learning shown by adolescents with autism spectrum disorder (ASD).


METHODS
A total of 21 high-functioning individuals with ASD aged 12 to 18 years, and 23 gender-, IQ-, and age-matched adolescents with typical development (TYP), completed a transitive inference (TI) task implemented using rapid event-related functional magnetic resonance imaging (fMRI). Participants were trained on overlapping pairs in a stimulus hierarchy of colored ovals where A>B>C>D>E>F and then tested on generalizing this training to new stimulus pairings (AF, BD, BE) in a "Big Game." Whole-brain univariate, region of interest, and functional connectivity analyses were used.


RESULTS
During training, the TYP group exhibited increased recruitment of the prefrontal cortex (PFC), whereas the group with ASD showed greater functional connectivity between the PFC and the anterior cingulate cortex (ACC). Both groups recruited the hippocampus and caudate comparably; however, functional connectivity between these regions was positively associated with TI performance for only the group with ASD. During the Big Game, the TYP group showed greater recruitment of the PFC, parietal cortex, and the ACC. Recruitment of these regions increased with age in the group with ASD.


CONCLUSIONS
During TI, TYP individuals recruited cognitive control-related brain regions implicated in mature problem solving/reasoning including the PFC, parietal cortex, and ACC, whereas the group with ASD showed functional connectivity of the hippocampus and the caudate that was associated with task performance. Failure to reliably engage cognitive control-related brain regions may produce less integrated flexible learning in individuals with ASD unless they are provided with task support that, in essence, provides them with cognitive control; however, this pattern may normalize with age.
University of California, Davis (UC Davis); UC Davis Imaging Research Center, Davis, CA; MIND Institute, Davis. Electronic address: marjorie.solomon@ucdmc.ucdavis.edu.
Marjorie
M
Solomon
University of California, Davis (UC Davis); UC Davis Imaging Research Center, Davis, CA.
J Daniel
JD
Ragland
University of California, Davis (UC Davis); UC Davis Imaging Research Center, Davis, CA.
Tara A
TA
Niendam
University of California, Davis (UC Davis); UC Davis Imaging Research Center, Davis, CA.
Tyler A
TA
Lesh
University of California, Davis (UC Davis).
Jonathan S
JS
Beck
University of California, Davis (UC Davis).
John C
JC
Matter
Brown University, Cognitive, Linguistic, and Psychological Sciences, Providence, RI.
Michael J
MJ
Frank
University of California, Davis (UC Davis); UC Davis Imaging Research Center, Davis, CA; MIND Institute, Davis; Center for Neuroscience of UC Davis.
Cameron S
CS
Carter
D000293:Adolescent; D000067877:Autism Spectrum Disorder / Q000503:physiopathology*; D000067290:Behavior Rating Scale; D001931:Brain Mapping; D002648:Child; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology*; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000473:pathology*; D017397:Prefrontal Cortex / Q000473:pathology*; D011340:Problem Solving; D011569:Psychiatric Status Rating Scales
adolescents; fMRI; learning; problem solving; reasoning