AHA/ASA Stroke Council Chair-elect and volunteer expert, Patrick D. Lyden, M.D., offers perspective (via Zoom) on ISC 20 presentations 11 and 114. He is Carmen and Louis Warschaw Chair in Neurology; professor, Neurology Cedars Sinai, Los Angeles, CA.
copyright American Heart Association 

"Arteries, they open and close normally, and that process of dilation or narrowing is controlled by the nerve fibers that coat the artery, and those nerve fibers can be stimulated just like we stimulate nerves in other parts of the body for other reasons."