The similarities between the pathways used by nerves and by blood vessels first struck anatomists hundreds of years ago; they appear clearly, for example, in the detailed drawings of Leonardo da Vinci. At the Society for Neuroscience meeting, researchers presented more than a dozen examples of neurovascular links in health and disease.

These connections suggest a common origin, research presented at SfN indicates; the signals first used by the nervous system were later “co-opted” and reused by the vascular system, Peter Carmeliet of the Flanders Interuniversity Institute for Biotechnology in Leuven, Belgium, said in a Presidential Special Lecture at the conference.
  Unlike any other organ, the brain depends on continuous blood flow. If the circulation to a portion of the brain is interrupted, within seconds that area will lose its ability to function. A prolonged interruption—as, for example, with a stroke—can cause permanent damage.

Current research on stroke exemplifies the way scientific work on blood-brain interaction has developed during the past several decades. Thomas Jacobs, program director of the Neural Environment Cluster at the National Institute of Neurological Disorders and Stroke, said that research in the 1980s focused mainly on the vascular aspects of stroke and in the 1990s on the neuronal aspects, but these approaches yielded only one major new therapy, the “clot-busting” drug tPA.

Hence, at the turn of this century, scientists widened their focus to include not only neurons but also the blood vessels surrounding them and the structural cells, known as the glia, that hold them together. “Research on this emerging concept of a neurovascular unit is providing new leads toward understanding how the brain communicates with its blood vessels,” Jacobs said.