Medullary and Hypothalamic Functional Magnetic Imaging During Acute Hypoxia in Tracing Human Peripheral Chemoreflex Responses

Hypoxia-sensitive peripheral carotid chemoreceptors, which regulate sympathetic outflow from the brain stem, are promising antihypertensive treatment targets. However, central nervous pathways integrating human chemoreflexes poorly understood. We combined high-resolution functional magnetic resonance imaging with physiological profiling to elucidate hypothalamic and medullary responses acute hypoxia. exposed 12 healthy men (29.7±6.6 years) 5 hypoxic episodes each by breathing 10% oxygen for 180 seconds followed 90 of normoxia during subcortical imaging. recorded beat-by-beat finger blood pressure, ECG, saturation (Sp o 2 ). analyzed data through independent component analysis, correlation systolic pressure Sp , connectivity analysis dual regression. On average decreased 12±3% ( P <0.01) hypoxia while heart rate increased 3±7 bpm <0.01). Systolic was unchanged. Brain stem-centered analyses revealed distinct hypoxia-responsive regions around nucleus solitary tract, ambiguus/intermediate reticular nucleus, dorsal motor vagal nerve, spinal trigeminal inferior olivary nucleus. Hypothalamus-centered 3 such arcuate anterior area/lateral area, paraventricular During hypoxia, these showed altered various areas. conclude that reveals systems engaged likely correspond chemoreceptor pathway. Our methodology may have utility in studying chemoreflex contributions cardiovascular disease modulation. Registration: URL: https://www.drks.de/ . Unique identifier: DRKS00013101.