Differences in the late positive potential in response to emotional stimuli in trauma-exposed people

Despite the high prevalence of post-traumatic stress disorder (PTSD; Kilpatrick et al., 2013), much is still unknown about the etiology of this debilitating condition. Dysregulated reactivity to emotional stimuli has been implicated in the maintenance and onset of PTSD symptoms (McLean & Foa, 2017; Nawjin et al., 2015). Neurobiological markers of emotional reactivity in response to emotional stimuli can help elucidate the relationship between post-trauma psychopathology and emotional processing. The late positive potential (LPP) is an event-related potential that is associated with emotional reactivity to salient stimuli and can be used as neural measure of dysregulated emotional processes in clinical and subclinical populations (Hajcak et al., 2010). However, results of studies of the relationship between the LPP in response to emotional stimuli and PTSD symptoms in trauma-exposed people have been mixed (e.g., DiGangi et al., 2017; Lobo et al., 2014). The purpose of the current study was to test the relationship between emotional reactivity, as measured by the LPP, and PTSD symptoms in trauma-exposed people. We hypothesized that trauma-exposed people will have greater LPP amplitude in response to negative stimuli than to positive or neutral stimuli, and that greater LPP amplitude to negative stimuli will be associated with greater severity of PTSD symptoms. Data from 76 trauma-exposed undergraduates were used. Participants viewed a series of negative, neutral, and positive images while ERPs were recorded. Negative images produced the highest LPP amplitudes, followed by positive and neutral images. However, LPP amplitudes to emotional images did not predict PTSD symptoms. These results suggest that trauma-exposed people experience stronger emotional reactions to negative compared to positive images. More work is needed to understand the relationship between emotional reactivity and PTSD symptoms.M.S.Includes bibliographical reference