(PS3-D79) The Relationship Between Neural Measure of Expectancy Violation and Dimensional Measure of Obsessive-compulsive Contamination-concerns

Expecting, or overestimating the probability of, a threatening outcome when encountering ambiguous events may contribute to the etiology and maintenance of Obsessive-Compulsive Disorder (OCD). Moreover, violations of these expectancies (i.e. Expectancy Violation; EV) is central to learning and may be the central ingredient of gold standard treatments for OCD (i.e., exposure and response prevention). However, existing studies have relied on self-report measures to validate whether EV has occurred. Event related potentials (ERPs), a component of the electroencephalogram (EEG), allow the assessment of EV in real time. Specifically, the P300 component may capture EV to unexpected stimuli. In the current study, we asked 69 participants to complete an EV Assessment in which ambiguous sentences that could lead to potential contamination concerns (i.e. “You are handed a towel that is…”) were followed with a benign (i.e., “white”) or threat-related (i.e., “soiled”) ending. The P300 was quantified separately following benign and contamination-related sentences. Participants also completed a validated self-report measure of OCD symptoms. We found a negative relationship between contamination concerns and the P300 amplitude following threat-endings, such that individuals with higher contamination-concerns had lower EV for threat-related stimuli. This finding suggests that participants with greater contamination fears expect to encounter threats in ambiguous scenarios at the neuronal level. If replicated and validated further, this measure of EV could represent a step forward in establishing an empirical measure of EV for studies of learning during exposure therapy.