title: Aversive life events enhance human freezing responses.
abstract: In the present study, we investigated the effect of prior aversive life events on freezing-like responses. Fifty healthy females were presented neutral, pleasant, and unpleasant images from the International Affective Picture System while standing on a stabilometric platform and wearing a polar band to assess body sway and heart rate. In the total sample, only unpleasant pictures elicited reduced body sway and reduced heart rate (freezing). Moreover, participants who had experienced 1 or more aversive life events showed greater reductions in heart rate for unpleasant versus pleasant pictures than those who had experienced no such event. In addition, relative to no-event participants, single-event participants showed reduced body sway to unpleasant pictures, while multiple-event participants showed reduced body sway in response to all picture categories. These results indicate that aversive life events affect automatic freezing responses and may indicate the cumulative effect of multiple trauma. The experimental paradigm presented is a promising method to study freezing as a primary defense response in trauma-related disorders.
authors.affiliation: Department of Clinical Health and Neuropsychology, Leiden University, P.O. Box 9555, Leiden 2300 RB, The Netherlands. mhagenaars@fsw.leidenuniv.nl
authors.forename: Muriel A
authors.initials: MA
authors.lastname: Hagenaars
authors.forename: John F
authors.initials: JF
authors.lastname: Stins
authors.forename: Karin
authors.initials: K
authors.lastname: Roelofs
mesh_terms: D000293:Adolescent; D000328:Adult; D001143:Arousal / Q000502:physiology; D004644:Emotions / Q000502:physiology*; D005260:Female; D046352:Freezing Reaction, Cataleptic / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008016:Life Change Events; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation; D011187:Posture / Q000502:physiology*; D011795:Surveys and Questionnaires