Valence-dependent coupling of prefrontal-amygdala effective connectivity during facial affect processing

Abstract Despite the importance of the prefrontal- amygdalanetwork for emotion processing, valence-dependent coupling within this network remains elusive. In this study, we assessed the effect of emotional valenceon brain activity and effective connectivity. We tested which functional pathways within the prefrontal- amygdalanetwork are specifically engaged during the processing of emotional valence. Thirty-three healthy adults were examined with functional magnetic resonance imaging while performing a dynamic faces and dynamic shapes matching task. The valenceof the facial expressions varied systematically between positive, negative, and neutral across the task. Functional contrasts determined core areas of the emotion processing circuitry, comprising the medial prefrontal cortex(MPFC), the right lateral prefrontal cortex, the amygdalaand the right fusiform face area. Dynamic causal modellingdemonstrated that the bidirectional coupling within the prefrontal- amygdalacircuitry is modulated by emotional valence. Additionally, Bayesian model averaging showed significant bottom-up connectivity from the amygdalato the MPFC during negative and neutral, but not positive, valence. Thus, our study provides strong evidence for alterations of bottom-up coupling within the prefrontal- amygdalanetwork as a function of emotional valence. Thereby our results not only advance the understanding of the human prefrontal- amygdalacircuitry in varying valencecontext, but, moreover, provide a model to examine mechanisms of valence-sensitive emotional dysregulationin neuropsychiatric disorders. Significance statement Recent neuroimaging studies have emphasized the importance of valence-sensitivity within the prefrontal- amygdalanetwork during emotion processing. Yet, it remains elusive which specific pathways are involved in processing affective information, and how this information is integrated in the brain’s network. In particular, the amygdala’s role in signaling valenceinformation to the cortex is subject to ongoing discussions. Moreover, as aberrant brain function has been found in the amygdalaand the prefrontal cortexin various debilitating psychiatric disorders, understanding the mechanisms of processing emotional stimuli with different valence(positive, negative, neutral) is particularly relevant for the field. Our findings indicate changes in coupling strength as a function of emotional valencewithin the prefrontal- amygdalanetwork.