The autonomic nervous system orchestrates the functions of internal organs such as the heart and gut, serving as a connection between the brain and the rest of the body. It is classified in two divisions—the sympathetic and parasympathetic systems, often described as the body’s accelerator and brake, respectively. For example, the sympathetic nervous system activates the “fight-or-flight” response in reaction to danger, concentrating energy on immediate survival and halting less urgent functions such as digestion.
Now, a new study from Caltech uncovers diverse neuron populations within the sympathetic nervous system and reveals how they control visceral functions in an organ-specific manner.
The research, titled “Organ-specific Sympathetic Innervation Defines Visceral Functions.” appearing in the journal Nature on November 27, was led by graduate student Tongtong Wang and conducted in the laboratory of Yuki Oka, professor of biology and Heritage Medical Research Institute Investigator. Research in the Oka lab focuses on understanding how the brain and body cooperate to maintain a healthy internal balance. In 2022, the team discovered a body-to-brain system that transmits signals about hydration levels. But the mechanisms by which the brain regulates other body functions, such as the fight-or-flight response, have long eluded scientists.