Neural Correlates of Congruency Sequence Effects in Autism Spectrum Disorders
43.422, Monday, May 13, 8:30 am - 12:30 pm, Orchid Ballroom
Kristina Denisova1, Zhishun Wang1, Yuankai Huo1, Bradley Peterson1; 1Division of Child and Adolescent Psychiatry, College of Physicians and Surgeons, Columbia University
Persons with Autism Spectrum Disorder (ASD) often exhibit stereotyped, repetitive, instead of flexible and appropriate behavior for a particular goal and context. We investigated how adjustments of cognitive resources in ASD, a developmental disorder, may be influenced by recent experiences with stimuli that have either competing or complementary dimensions (i.e., influence of "trial history"; Gratton, 1992). Previous work has shown that experiencing stimuli features that are incompatible with an internal goal slows down performance on the current trial (thus producing "interference"), but facilitates processing on a subsequent conflict trial, as manifested in speeded RTs and increased accuracy (e.g., Botvinick et al., 2001). Functional MRI and behavioural data were acquired from children and adults with ASD (N=55) and typically developing controls (N=78), matched by age, IQ, and gender. Participants performed a stimulus-response compatibility task (Simon, 1969) by judging the direction of left- or right-facing arrow, while ignoring its spatial location. We found that ASD and TD participants responded more quickly to current congruent trials compared to incongruent trials (F(1,131) = 124.419, p <0.000). In both groups RTs were faster on a current incongruent trial if a preceding trial was another incongruent trial, F(1,131)= 77.386, p<0.000, an effect called conflict adaptation. Dorsal Anterior Cingulate Cortex (dACC) and Left Inferior Frontal Gyrus (left IFG) activity was associated with processing of interference from incongruent dimension in both TD and ASD groups, with ASD showing significantly more DLPFC activity compared to TD group. However, only TD group showed context-specific conflict adaptation activation in DLPFC, mirroring the behavioural pattern. ASDs capability to suppress or inhibit prepotent responses is sustained by a network of associative cortices and sub-cortical regions. DLPFC activity was attenuated in ASD depending on previous trial conflict history, perhaps reflecting a decreased neural contribution of DLPFC to flexible processing in ASD.