On 25 June 2026, the CRC 1744 Seminar Series welcomed Dr. Marine Tournissac from the Vision Institute in Paris (CNRS) as guest speaker, hosted by Arthur Liesz (Project B01).

Marine Tournissac uses hypercapnia, controlled exposure to elevated CO₂, as a tool to probe how blood vessels in the brain respond and regulate themselves. Her work challenges a common assumption: that CO₂ plays a direct role in neurovascular coupling, the mechanism by which neural activity drives local blood flow changes. Her findings show that the two processes are in fact distinct. While CO₂ induces acidification in the arteriole wall and surrounding space, this does not interfere with neurovascular coupling – CO₂ is not its mediator.

Her work also reveals that the cerebral vasculature is far from a passive pipe: different vascular compartments, arteries and veins, follow different rules. The acidification triggered by CO₂ is spatially restricted, concentrated at the arterial side, with distinct dynamics compared to venous responses. This compartmentalised view of vascular regulation opens new questions about how CO₂ exchange at the blood-brain interface shapes cerebrovascular function and what happens when it goes wrong in disease.

We thank Dr. Tournissac for a stimulating discussion and look forward to future collaborations.