Saturday, May 22, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
11:00 AM
Background: Children and adolescents with High-Functioning Autism often demonstrate impulsive behaviors, possibly due to impaired sensitivity to stimulus-response contingencies and the ability to predict reward. The neurobiological mechanisms underlying these deficits have not been thoroughly explored, but can be examined using the ‘feedback-related negativity’ (FRN)—an event-related potential (ERP) component evoked following performance or response feedback (e.g., whether a monetary reward is obtained), with greater-amplitude FRN following unfavorable than favorable outcomes and following unexpected, relative to predicted, unfavorable outcomes.
Objectives: We know of no published study that has directly measured the FRN in autism. Because EEG is generally well-tolerated by individuals with higher-functioning ASD, we designed a study using a child-friendly task (choosing balloons of different colors) that has previously shown deficits in emotion regulation in adolescents with early life cocaine exposure (Crowley et al., 2009), to examine the possibility of similar deficits in ASD.
Methods: We examined ERPs elicited by favorable (monetary gain; ‘reward’) and unfavorable (no monetary gain; ‘non-reward’) feedback during a guessing task where expectation of reward outcome was manipulated (75% or 25% probability of reward counterbalanced across two blocks of 200 trials) in 25 children and adolescents diagnosed with ASD and 25 age- and IQ-matched healthy participants.
Results: Replicating previous work, controls showed larger amplitude FRN to ‘non-reward’ feedback and largest amplitude FRN following ‘non-reward’ when ‘reward’ feedback was expected (i.e., when reward probability was greatest). The same was true for the ASD group. However, inspection of correlation matrices observed a strong association between Verbal IQ and measures of the FRN. Regression analyses that included VIQ in the model consistently showed that VIQ explained a significant amount of the variance in FRN in both ASD and comparison groups, in fact washing out the significance of the difference between reward and non-reward trials.
Conclusions: We discuss the implications for understanding of decision making, learning, and motivation in ASD in the context of no significant differences in Feedback-related negativity compared to controls. More importantly in our view, we know of no previous studies that have reported the influence of IQ on the FRN even in healthy development, perhaps because it has never been measured. Although it is a serendipitous finding, this has important potential applications for understanding how we measure the reward system in both typical and atypical development.
Objectives: We know of no published study that has directly measured the FRN in autism. Because EEG is generally well-tolerated by individuals with higher-functioning ASD, we designed a study using a child-friendly task (choosing balloons of different colors) that has previously shown deficits in emotion regulation in adolescents with early life cocaine exposure (Crowley et al., 2009), to examine the possibility of similar deficits in ASD.
Methods: We examined ERPs elicited by favorable (monetary gain; ‘reward’) and unfavorable (no monetary gain; ‘non-reward’) feedback during a guessing task where expectation of reward outcome was manipulated (75% or 25% probability of reward counterbalanced across two blocks of 200 trials) in 25 children and adolescents diagnosed with ASD and 25 age- and IQ-matched healthy participants.
Results: Replicating previous work, controls showed larger amplitude FRN to ‘non-reward’ feedback and largest amplitude FRN following ‘non-reward’ when ‘reward’ feedback was expected (i.e., when reward probability was greatest). The same was true for the ASD group. However, inspection of correlation matrices observed a strong association between Verbal IQ and measures of the FRN. Regression analyses that included VIQ in the model consistently showed that VIQ explained a significant amount of the variance in FRN in both ASD and comparison groups, in fact washing out the significance of the difference between reward and non-reward trials.
Conclusions: We discuss the implications for understanding of decision making, learning, and motivation in ASD in the context of no significant differences in Feedback-related negativity compared to controls. More importantly in our view, we know of no previous studies that have reported the influence of IQ on the FRN even in healthy development, perhaps because it has never been measured. Although it is a serendipitous finding, this has important potential applications for understanding how we measure the reward system in both typical and atypical development.