Adrenomedullary responses to non-invasive cortical stimulation in humans

Abstract Introduction: The discovery of cortical adrenomedullary projections in cebus monkeys suggests that similar pathways exist humans. Notably, the major corticoadrenomedullary projection regions have human equivalents can be stimulated non-invasively with repetitive transcranial magnetic stimulation (rTMS). If rTMS used to selectively modulate activity, there may significant therapeutic benefits for stress-, affective-, or neuroimmune-related disorders. Purpose: To assess resting and stress-induced neuroendocrine responses continuous (cTBS) intermittent (iTBS) theta burst TMS Methods: 39 healthy young adults (14W) were randomly assigned three counterbalanced sessions iTBS (n=19) cTBS (n=20). Stimulation was applied motor areas contain majority non-human primates (primary cortex trunk region (M1TRUNK) presupplementary area (preSMA)). M1 leg (M1LEG) as a spatial control. locations determined based on TMS-evoked electromyographic rectus abdominus vastus lateralis using combination fMRI activity metanalytical structural coordinates (preSMA). All procedures performed 96mm curved double coil stereotactic navigation. TBS 600 biphasic pulses at 80% AMT. Corticoadrenomedullary corticospinal excitability (CSE) assayed before after TBS, immediately maximal exercise, 60min 90min plasma epinephrine concentrations median MEP AUC, respectively. Initial analysis made 2 (protocol) x 3 (visit) 5 (time-point) mixed methods ANOVA. Results Conclusions: As expected, exercise resulted large increase (p<0.0001, 8-fold) overall. Ongoing indicates target-specific changes are likely, CSE, often paradoxical. Our preliminary results also suggest subthreshold principally stress inducible. Research Category Technology Methods Translational Research: 10. Transcranial Magnetic (TMS) Keywords: Adrenal Medulla, Cortex, Sympathetic Nervous System, Non-Invasive Brain