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 traumarelated disorders.

Cognitively and socially induced stress affects postural control

“…Our results suggest that the emotional contexts that affect postural sway may not only be postural threat and passive viewing of aversive images but also stress induced using cognitive and SET contexts. We show a reduction in sway with SET, which is in line with studies on postural threat (Carpenter et al 1999(Carpenter et al , 2001Adkin et al 2000) and aversive or threatening images (Azevedo et al 2005;Hagenaars et al 2012;Roelofs et al 2010), suggesting that the reduction in sway in the present study could be evidence for a common 'freezing' or 'stiffening' mechanism in response to increased threat, anxiety, and stress. However, it is important to acknowledge that to make a strong claim about a stiffening or freezing strategy, it is critical to also show an increase in sway frequency, but our results did not show this increase.…”

“…For example, studies assessing postural threat and fear of falling have primarily used electrodermal activity which measures skin conductance, showing that it is a reliable measure of postural threat (Cleworth et al 2012;Osler et al 2013). On the other hand, studies using passive viewing of threatening images used heart rate, based on the idea from the animal literature that freezing is accompanied by bradycardia (Azevedo et al 2005;Hagenaars et al 2012;Roelofs et al 2010). Furthermore, studies assessing stress using social evaluative threat have used cortisol measures (e.g., Dedovic et al 2013).…”

“…Similarly, Roelofs et al (2010) showed a freezing response in reaction to angry faces, reflected in reduced heart rate and body sway, and Hillman et al (2004) showed a backward body movement away from unpleasant stimuli in women which was not observed in the case of pleasant or neutral stimuli. This response was also affected by the previous experience of an aversive life event, with individuals who had experienced such an event showing a greater reduction in sway when exposed to aversive images compared with a control group (Hagenaars et al 2012). However, another study manipulating arousal and valence using this paradigm (Horslen and Carpenter 2011) showed that only arousal affected postural sway similar to postural threat, and identified methodological limitations in some of the passive-viewing studies.…”

Biomechanical organization of gait initiation depends on the timing of affective processing

“…Posturographic studies have revealed that potent emotional triggers may activate innate behavioral tendencies, such as freeze, fight, or flight responses [2][3][4]. These responses may play into the neural control of balance, where they become visible as automatic postural adjustments.…”

The role of automatic defensive responses in the development of posttraumatic stress symptoms in police recruits: protocol of a prospective study

“…Freezing is generally considered as adaptive stress-coping mechanism, and the timing of the transition from passive freeze to active fight-or-flight may be essential for optimal decision-making under threat. Maladaptive, exacerbated freezing was observed in anxious (Roelofs, Hagenaars, & Stins, 2010) and trauma-exposed (Hagenaars, Stins, & Roelofs, 2012) individuals, as well as in adolescents with insecure attachment during infancy (Niermann et al, 2015). Moreover, self-reported tonic immobility during trauma exposure was predictive for the development of PTSD symptoms after sexual assault (Bovin, Jager-Hyman, Gold, Marx, & Sloan, 2008).…”