Microinfarctions are present in the aged and injured human brain. To examine the consequences of microinfarcts, Shih and coworkers used controlled optical methods to create occlusions of individual penetrating arterioles or venules in rat cortex. Targeting of multiple vessels resulted in tissue damage that coalesced across the cortex, even though intervening penetrating vessels were acutely patent. Single microinfarcts, targeted to encompass all or part of a cortical column, impaired behavioral performance. Post-occlusion administration of memantine, a glutamate receptor antagonist that reduces cognitive decline in Alzheimer’s disease, was effective in reducing tissue damage and perceptual deficits. The authors suggest that collectively, microinfarcts likely contribute to cognitive decline. Treatments which protect against excitotoxicity may be successful in treating the progressive nature of vascular dementia.
Shih AY, Blinder P, Tsai PS, Friedman B, Stanley G, Lyden PD and Kleinfeld D: The smallest stroke: occlusion of one penetrating vessel leads to infarction and a cognitive deficit. Nature Neuroscience 16: 55–63 (2013).