Abstract
Background: Two areas of importance in stress reaction are the anterior cingulated cortex (ACC) and the Amygdala. Previous studies showed that especially the dorsal ACC (dACC) influences the generation of autonomic arousal (Critchley et al., 2003). It was also found that the dACC is activated under cognitive stress (Falkenbeg et al., 2012). Thus, the dACC seems to be an important area controlling stress reactivity. Neurexan®, a medicinal product sold over the counter (OTC), contains four ingredients, Passiflora incarnata (passionflower), Avena sativa (oats), Coffea arabica (coffee) and Zincum isovalerianicum (zinc valerianate). Neurexan® has been investigated in patients with symptoms related to acute stress, nervousness/restlessness, and insomnia. The underlying neuronal mechanisms that lead to the reduction of those symptoms are less clear. In this study we explore whether Neurexan® induces changes in the activation of dACC and associated areas during a stress task.
Method: Thirty-nine healthy male volunteers participated in a randomized, placebo-controlled, double-blind, two-period-crossover trial. The effects of treatment were measured after a single dose of Neurexan or placebo by 3 Tesla fMRI. The stress response was induced using the ScanSTRESS (Streit et al., 2014), which uses arithmetic tasks as well as mental rotation tasks. Additionally the stress response was measured by saliva cortisol concentration and visual analogue scales (VAS) for nervousness and anxiety.
Results: After correcting for multiple testing in the region of interest (right dACC) paired t-test analysis showed a significant activation cluster (peak level p=0.027, FWE-corrected) in rotation stress condition as compared to stress control. Stress induced activity in the right dACC was reduced by Neurexan treatment as compared to placebo. No effect in dACC was found for arithmetics conditions.
Conclusion: The intake of single dose of Neurexan® significantly reduces right dACC activation during psychosocial stress compared to the intake of placebo.
