Supplementary Material for: Hypothalamic Deep Brain Stimulation Influences Autonomic and Limbic Circuitry Involved in the Regulation of Aggression and Cardiocerebrovascular Control in the Göttingen Minipig

Background: Deep brain stimulation (DBS) in the ventral tuberal hypothalamus (VTH) is currently under investigation for the treatment of severe obesity. Stimulation impact on a number of closely related hypothalamic neural systems could potentially influence normal hypothalamic function and thereby generate adverse side effects. Objective: To assess the feasibility and safety of VTH DBS in a non-primate large animal model. Methods: In the VTH of 6 Göttingen minipigs, quadropolar leads were implanted bilaterally (n = 2) or unilaterally (n = 4), using optimized MRI sequences allowing identification of major diencephalic landmarks. Heart rate, weight, behavior and nighttime locomotor activity were recorded throughout the study period. Two of the unilaterally implanted minipigs were examined with [¹⁵O]H₂O positron emission tomography (PET) scans performed in DBS-off and DBS-on mode. Results: VTH DBS elicited an amplitude-dependent increase in heart rate and transient aggressive behavior. PET demonstrated that VTH DBS caused a global increase in cerebral blood flow velocities and decreased mean transit time. Conclusions: VTH DBS results in behavioral and physiological changes, which may derive from activation of closely related limbic and autonomic networks. Caution and further studies of longer length should be requested before this procedure is used more widely in humans.