Seminar: Mapping the Central Autonomic Network with Task-Based BOLD fMRI

Student: Wilmer Alfonzo Ramos

Supervisors: Dr. Nathan Churchill and Dr. Vladislav Toronov

Abstract

The central autonomic network (CAN) coordinates cardiovascular, respiratory, and homeostatic regulation. Mapping its function may help clarify the mechanisms underlying autonomic symptoms observed in concussion, traumatic brain injury, long COVID, anxiety disorders, cardiovascular disease, and neurodegenerative conditions. This pilot study evaluated the feasibility of task-based blood oxygenation level–dependent (BOLD) functional MRI for characterizing CAN responses during standardized autonomic challenges. Twenty-three healthy adults underwent 3-T MRI with synchronized respiratory and pulse monitoring during cold pressor, isometric handgrip, breath-hold, and paced-breathing tasks. Preliminary analyses examined task-evoked activation maps and insular responses across repeated trials. The tasks produced distinct patterns of BOLD activation and deactivation in CAN-related regions. Breath-hold elicited prominent responses in the bilateral insula, thalamus, and midbrain, while paced breathing showed prominent anterior cingulate activation and weaker insular responses. Cold pressor and handgrip produced mixed activation and deactivation patterns, including insular signal decreases. Insular responses during paced breathing showed broadly similar temporal patterns across four repeated trials. These findings support the feasibility of using autonomic challenges to map BOLD responses within central autonomic circuitry. Ongoing analyses will quantify physiological confounds and evaluate response reliability in an expanded healthy cohort. With further validation in clinical populations, this framework could help determine whether altered central autonomic function contributes to persistent symptoms following concussion and in long COVID, including dizziness, palpitations, and fatigue. Ultimately, functional mapping of the CAN may support the identification of neural correlates of autonomic symptoms and the development of objective measures to characterize dysfunction and assess treatment response.