Photo of Prof. Rae Silver


On August 8, 2023, Rae Silver, Helene L. and Mark N. Kaplan Professor of Natural & Physical Sciences, published a new article in the Journal of Biological Rhythms, alongside Barnard affiliates Alana Taub ’18, Ruya Tazebay ’24, and research scientist Joseph Lesauter, titled “Vasculature of the Suprachiasmatic Nucleus: Pathways for Diffusible Output Signals.” 

This study builds on previous research conducted by Silver and colleagues in 2021, published in Nature Communications, that demonstrated the existence of a portal pathway in a mouse’s brain, with capillary blood vessels linking the brain’s suprachiasmatic nucleus (SCN) to those of the organum vasculosum of the lamina terminalis (OVLT), a circumventricular organ. Before this study, there had only been one known portal pathway in the mammalian brain, the pituitary gland.

Portal pathways are important because they enable low concentrations of neurosecretions to reach specialized local targets without dilution in the systemic circulation. This new study conducted by Silver and her colleagues expands upon their findings from 2021 by investigating the blood vessels of the core and shell SCN in mouse brains to explore the SCN vasculature and the capillary vessels whereby SCN neurosecretions might reach portal vessels.

The study findings suggest three important hypotheses. First, the distinct arterial and venous systems of the rostral (toward the front of the brain) and caudal (toward the back of the brain) SCN may contribute to the in vivo variations of metabolic and neural activities observed in SCN networks. Second, the dense capillaries of the SCN shell are well positioned to transport blood-borne signals. Finally, variations in SCN vascular supply and drainage may contribute to differences in different animal species. Silver and her colleagues’ work marks an exciting step in our increased understanding of the ways in which diffusible signals act within the brain.