In the metropolis that is our brain, the gray matter represents the buildings, and the white matter represents the wires that connect them all together. Unfortunately, cerebral white matter is extremely vulnerable in diseases that affect cerebral blood flow, such as stroke and vascular dementia, effectively cutting off communication between brain regions. Why is the white matter so prone to injury? One likely possibility is that the small blood vessels supplying white matter are more delicate and die off more quickly during brain pathology, compared to blood vessels of gray matter. Indeed, studies have shown that pericytes that line and support brain capillaries are lost more quickly in the white matter during ischemia. Without pericytes, the capillaries start to leak and their ability to flow degrades, leading to degeneration of neuronal axons and their myelin sheaths.
The Albert Institute for White Matter has funded a pilot project in our lab focused on visualizing pericytes in callosal white matter fibers of live mice. The project will use deep two-photon imaging and red-shifted fluorescent proteins to improve imaging of pericytes in this deep and hard to reach structure. We are excited that this grant supports a collaboration with the lab of Dr. Tom Carmichael at UCLA, who will produce new tools to express fluorescent proteins in pericytes and share expertise in white matter stroke models.