The scalp prefrontal-limbic functional connectivity moderates stress-related rumination effects on stress recovery.

Background: Mood disorders are often associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction, and rumination has been implicated in delayed cortisol recovery. However, research findings on the impact of rumination on cortisol recovery have been inconsistent. The moderating effects of scalp prefrontal-limbic connections on the relationship between rumination and cortisol recovery may explain these discrepancies.

Method: Acute stress was induced by a 5-min simulated job interview. Salivary samples and affective ratings were collected at seven pre-determined time points. After the simulated job interview, 35 healthy adult participants were randomly assigned to either the rumination condition (n = 17) or the distraction condition (n = 18).

Results: Inducing stress and rumination led to increased cortisol levels, negative mood, and state rumination. Compared with the distraction group, the rumination group displayed delayed cortisol recovery and decreased scalp prefrontal-limbic connectivities, that is, left ventrolateral prefrontal cortex (LVLPFC) and left temporal area (LTMP) [ps < .05], and right dorsolateral prefrontal cortex (RDLPFC) and anterior cingulate cortex (ACC) [ps < .05]. The relationship between rumination and cortisol recovery was moderated by connectivities between the left dorsolateral prefrontal cortex (LDLPFC) and LTMP, RDLPFC and LTMP, LDLPFC and ACC, and RDLPFC and ACC [B = -0.98 to -0.35, SE = 0.15-0.34, ps < .05]. Higher rumination combined with reduced scalp prefrontal-limbic connectivities to predict delayed cortisol recovery.

Conclusion: The current findings suggest that scalp prefrontal-limbic connectivity is a neural underpinning related to emotion regulation for the effects of state rumination on stress recovery. These findings also provide a potential target for non-invasive intervention in HPA axis dysregulation.