Central autonomic network functional connectivity: correlation with baroreflex function and cardiovascular variability in older adults

Baroreflex regulates short-term cardiovascular variability via the autonomic neural system. The contributions of the central autonomic system to the baroreflex regulations of arterial blood pressure (BP) and heart rate have been reported in young healthy adults, but not in older adults. Therefore, we investigated the association between the high-level central autonomic network (CAN) connectivity and baroreflex sensitivity (BRS) under a resting condition in a healthy older population. Twenty-two older adults (68 ± 8 years old) underwent BRS assessment using the modified Oxford and transfer function methods. Resting-state brain functional MRI was performed to assess the CAN functional connectivity at rest. We found that the functional connectivity (FC) between the left amygdala and left medial frontal gyrus (MeFG), bilateral postcentral gyri and bilateral paracentral lobules (PCL) is associated with BRS and R-R interval (RRI) variability in the low-frequency (LF) range. Compared to the left amygdala, the FC map of the right amygdala only showed significant associations with BRS in the anterior cingulate cortex (ACC) and with RRI variability in the left occipital region. In addition, post hoc analysis of the functionally defined left insula sub-region confirmed the association between CAN and BRS. Overall, our study demonstrates that CAN and its related brain regions may be involved, likely in a left-lateral manner, in peripheral cardiac autonomic regulation at rest. The results highlight the potential importance of brain neural network function in maintaining cardiovascular homeostasis in older adults.