I read with interest the discussions by Ginsberg1 and Grotta2 and the conclusion by Hachinski.3 Despite the self-evident biochemical similarities of all mammalian brains, it is clear that there must be some difference that accounts for the failure of numerous stroke therapy trials. Careful consideration of the question being asked clarifies the issue.
Large brains (and other organs) need vascular systems because diffusion is not sufficient to provide nutrients and remove wastes. This is a result of the fact that surface area increases as the two-thirds power of mass. Clearly then, a sufficiently large brain must have a facilitated diffusion or convective flow system. Stroke merely consists of the local (or global) failure of this system, followed by death of cells that are not able to subsist by diffusion.
This two-thirds power relationship also means that a sufficiently small portion of the brain can subsist indefinitely by
Neff SR. Rodent Models of Stroke. Arch Neurol. 1997;54(4):350–351. doi:10.1001/archneur.1997.00550160005002
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