Abstract
Objective: Neurexan®, a medicinal product sold over the counter (OTC), contains passionflower, oat, coffee and zinc valerianate. Neurexan® has been investigated in patients with symptoms related to acute stress, nervousness and insomnia. Amygdala is involved in the development of fear and emotional behavior. Acute stress sensitizes the amygdala, thereby increasing vigilance/anxiety, which in turn promotes the stress response. Amygdala reactivity to negative stimuli is a reliable phenotype that closely associates with stress regulation and can be assessed with Hariri paradigm. Furthermore, a linkage between an increased level of stress hormones and increased emotional response to angry faces has been shown in patients with social phobia. Previous investigation suggested an attenuated euroendocrine
stress response in healthy volunteers induced by Neurexan®.
Thus, our aim was to further explore the effect of Neurexan® on the emotional brain response in the amygdala.
Methods: In a randomized, placebo-controlled, double-blind, twoperiod crossover trial brain response to the Hariri task, an emotional paradigm, of 39 healthy, moderate stressed males was measured after intake of a single dose of Neurexan® and placebo control via 3 Tesla functional magnetic resonance imaging. Data were preprocessed and
analyzed in SPM12. Amygdala was anatomically defined by the AAL (Automated Anatomical Labelling Atlas).
Results: Hariri task was firstly validated for negative emotional faces response. Significant (peak level FWE corrected) bilateral activations of fusiform gyri, amygdalae and prefrontal cortex as well as unilateral activation in right thalamus were confirmed as previously reported.
Paired t-test showed a treatment effect (p\0.05) in the left amygdala, with stronger activations in placebo than in Neurexan® condition.
Conclusion: We found a significant reduction of BOLD response to negative faces in the left amygdala during the Neurexan® session as compared to placebo. Neurexan® reduced the emotional brain response to negative stimuli.
