Functional MRI investigations of emotional processing and autonomic responses in patients with autonomic hyperactivity

Introduction Previous functional imaging studies provide evidence for neural integration of human emotions and autonomic bodily responses. However it remains unclear how primary autonomic disorders influence emotional processing. The present functional MRI study investigates how heightened bodily reactivity shape excessive emotional responses. Methods We recruited patients with autonomic hyperreactivity (postural tachycardia syndrome, POTS) and age-matched normal controls. Participants were scanned with heart rate recording when judging emotional pictures, consisting of five emotion-specific categories of faces and scences (happy, angry, disgust, sad, and neutral) taken from the Karolinska Directed Emotional Faces (KDEF) and the International Affective Picture System (IAPS). After scanning, participants completed questionnaires for anxiety (STAI), depression (BDI-II), and panic disorders (PDSS). Results The scores of the questionnaires indicated that the POTS patients showed significantly higher state and trait anxiety, higher depressive status, and nearly half of the patients had past experience of pacic attacks. At the physiological level, the POTS patients showed an excessive rise in heart rate from onset of each stimulus presentation when compared to controls. The results of the fMRI data showed much greater deactivation within ventromedial prefrontal cortex (VMPFC, BA11, Figure 1 & 2) and right dorsolateral prefrontal cortex (BA9) in the patients compared to controls. In contrast, greater activation in midline structures; precuneus (BA7), anterior prefrontal cortex (BA10), and rostral anterior cingulate cortex, were found in the patients compared to controls. Further investigations showed that globus pallidus (GP), pons, and VMPFC were significantly correlated with higher state anxiety in the patients. Causal mediation analysis revealed that the activation in VMPFC provoked the activation in GP mediated via the level of state anxiety in the patients. Conclusions Overall findings suggest that hyperreactive bodily states trigger disruptive emotional status by increased attenuation of activity within VMPFC impacting on GP function. Our study highlights the possible neural mechanisms for understanding emotional disturbance in autonomic hyperreactivity disorders