Vascular Structure & Hemodynamics

Although the brain typically makes up only 2% of our body weight, it consumes approximately 20% of our total generated energy. In addition, since there are limited energy reserves in the brain, neural function is critically dependent on a constant supply of blood to deliver oxygen and glucose. Our lab investigates a number of aspects of this vital infrastructure system using structural imaging and analysis, in vivo imaging, and mathematical modelling.

The structure of networks has a major impact on their function. We use high-resolution imaging techniques and computer vision algorithms to extract anatomical information from cerebrovascular networks, and analyse the relationship between their structure and function.

In the smallest blood vessels, it is no longer accurate to consider blood as a simple (Newtonian) fluid, since the presence of red blood cells (RBCs) has a significant effect. Using simulations, ex vivo measurements, and in vivo imaging, we are investigating the influence of RBCs on fluid dynamics at microvascular bifurcations.

Increases in local neural activity lead to increases in the supply of blood to that region, although the mechanisms responsible remain unclear. We are developing spatio-temporal models of blood flow in large-scale, realistic vascular networks to investigate the (auto)regulation processes relevant under these conditions.

Recently developed oxygen sensors make it possible to measure local oxygen levels in vivo. We are using two-photon phosphorescence lifetime imaging of these sensors to investigate the spatial and temporal dynamics of cerebral oxygen concentration at rest and during neural activation.

Although the overwhelming majority of oxygen in the blood is carried by red blood cells (RBCs), not plasma, most models of oxygen transport assume that blood is a uniform liquid. We are developing more detailed models that take into account the movement of discrete RBCs in order to investigate oxygen transport dynamics at the microvascular scale.