۱- Introduction

۲- Methods

۳- Results

۴- Discussion

References

Abstract

Emotional stress responses, encompassing both stress reactivity and regulation, have been shown to differ between men and women, but the neural networks supporting these processes remain unclear. The current study used functional neuroimaging (fMRI) to investigate sex differences in neural responses during stress and the sex-specific relationships between these responses and emotional stress responses for men and women. A significant sex by condition interaction revealed that men showed greater stress responses in prefrontal cortex (PFC) regions, whereas women had stronger responses in limbic/striatal regions. Although men and women did not significantly differ in emotional stress reactivity or subjective reports of stress regulation, these responses were associated with distinct neural networks. Higher dorsomedial PFC responses were associated with lower stress reactivity in men, but higher stress reactivity in women. In contrast, while higher ventromedial PFC stress responses were associated with worse stress regulation in men (but better regulation in women), dynamic increases in vmPFC responses during stress were associated with lower stress reactivity in men. Finally, stress-induced hippocampal responses were more adaptive for women: for men, high and dynamically increasing responses in left hippocampus were associated with high stress reactivity, and dynamic increases in the left (but not right) hippocampus were associated with worse stress regulation. Together, these results reveal that men and women engage distinct neural networks during stress, and sex-specific neural stress responses facilitate optimal emotional stress responses.

Introduction

Negative and uncontrollable events, or stressors, trigger multiple affective and cognitive responses. These include subjective feelings, or stress reactivity, which help signal that the organism is in a stressful situation, as well as stress regulation, which supports cognitive, emotional and behavioral coping to address the distress, the stressor itself and learning to build resilience and adaptation (Sinha, 2008). Thus, both emotional reactivity and timely, flexible modulation of these reactions are adaptive (Gratz and Roemer, 2004; Hartley and Phelps, 2010) and may facilitate optimal responding to stressors to build resilience. Research on stress and emotion processing has highlighted the neural circuitry supporting these responses. For example, early reactivity to acute stressors has been associated with increased signal (measured using functional neuroimaging) in the “salience network”, encompassing subcortical and limbic regions including the amygdala, anterior insula, and striatum (Hermans et al., 2014; van Oort et al., 2017). Connectivity within this network during stress was positively associated with negative affect (Hermans et al., 2011) and these regions are also involved in the generation of emotional responses (Ochsner et al., 2012). The hippocampus has also been associated with emotional reactivity (Kober et al., 2008; Phelps, 2004), stress-related health issues (Seo et al., 2014) and regulation, particularly of the physiological components of the stress response (Herman et al., 2012).