January 25, 2021

Dynamic integration and segregation of amygdala subregional functional circuits linking to physiological arousal

The dynamical organization of brain networks is essential to support human cognition and emotion for rapid adaption to ever-changing environment. As the core nodes of emotion-related brain circuitry, the basolateral amygdala (BLA) and centromedial amygdala (CMA) are recognized as two major amygdalar nuclei that regulate distinct affective functions and internal autonomic responses via their unique connections with cortical and subcortical structures in rodents. However, little is known how the dynamical organization of emotion-related brain circuitry reflects internal autonomic responses in humans. Using resting-state functional magnetic resonance imaging (fMRI) with concurrent recording of skin conductance, we show robust dynamic integration and segregation states of amygdala subregion-related intrinsic functional networks linked to spontaneous autonomic arousal. To be specific, time-varying connectivity analysis of resting-state fMRI data with K-means clustering approach revealed two distinct states of BLA- and CMA-based connectivity patterns, with a segregation state showing generally stronger BLA- than CMA-based connectivity with cortical regions, and an integration state showing substantial overlapping, in a spatio-temporal manner, between BLA- and CMA-based connectivity networks. Further analysis of skin conductance revealed significantly higher physiological arousal during the integration state than the segregation state, and state-specific BLA- and CMA-based connectivity with distinct subcortical and neocortical targets were predictive of spontaneous fluctuations of skin conductance. Our findings characterize dynamic functional organization of emotion-related amygdala nuclei circuits and networks and its links to spontaneous autonomic arousal in humans.

 bioRxiv Subject Collection: Neuroscience

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