Friday, May 21, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
3:00 PM
S. J. Weng
,
Department of Psychology, University of Michigan, Ann Arbor, MI
M. Carrasco
,
Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI
J. R. Swartz
,
Department of Psychology, University of Michigan, Ann Arbor, MI
J. L. Wiggins
,
Department of Psychology, University of Michigan, Ann Arbor, MI
N. Kurapati
,
Psychology, University of Michigan, Ann Arbor, MI
I. Liberzon
,
Department of Psychiatry, University of Michigan, Ann Arbor, MI
S. Risi
,
The University of Michigan Autism and Communication Disorders Center, University of Michigan, Ann Arbor, MI
C. Lord
,
University of Michigan, Ann Arbor, MI
C. S. Monk
,
Department of Psychology, University of Michigan, Ann Arbor, MI
Background:
Autism spectrum disorders (ASD) involve a core deficit in social functioning and impairments in the ability to recognize face emotions. Adolescence is a period where the social environment of peers can increase in complexity and others have reported that younger adolescents might have poorer social functioning than adolescents at older ages. Despite these reports, no known study has examined the association of age and amygdala function in ASD during adolescence. Moreover, there have been inconsistencies among studies surrounding the patterns of activation in neural structures involved in face processing. These conflicting reports can be partly explained by group differences in attention allocation to face stimuli. It is therefore crucial that neuroimaging studies on face processing, limit differences in attention between groups. Consequently, we adopted an emotional faces task designed to constrain group differences in attention in a sample of adolescents with ASD and typical controls. We used functional MRI to characterize activation in the amygdala, ventral prefrontal cortex (vPFC), and striatum, three structures involved in socio-emotional processing, in adolescents with ASD. Objectives:
The present study had two objectives. The first objective was to examine amygdala, ventral prefrontal and striatal function in ASD and control adolescents during the viewing of socio-emotional stimuli (facial expressions). The second objective was to characterize how amygdala activation relates to age during adolescent development for individuals with ASD. Methods:
Twenty-two adolescents with ASD and 20 healthy adolescents viewed emotional (happy, fearful, and sad) and neutral faces that were briefly presented (250ms) during functional MRI acquisition. To monitor attention, subjects were asked to identify the gender of each face. Results:
Relative to healthy adolescents, those with ASD showed greater activation in the amygdala, t(40)=2.29, p=.027, vPFC, t(40)=2.65, p=.011 and striatum, t(40)=3.30, p=.002 to faces relative to baseline (corrected for multiple comparisons). Additionally, in the contrast of sad vs. baseline, adolescents with ASD relative to controls demonstrated greater bilateral activation in the amygdala, vPFC and striatum. To establish statistical significance, we used a small volume correction approach false discovery rate (FDR) p<.05 on these regions of interest (ROIs). Moreover, in the ASD group, there was a negative correlation between age and mean activation from the whole bilateral amygdala region of interest (t(39)=1.94 , p=.060); younger adolescents showed greater activation than older adolescents. There were no group differences in accuracy or reaction time in the gender identification task. Conclusions:
The present findings suggest that neural correlates of ASD may be characterized as heightened activation of socio-emotional structures when group differences in attention are minimized. The heightened activation of the amygdala is most pronounced when youth with ASD are transitioning into adolescence.
