I'm pretty sure that you could enter a lab as a post-doc, just like a PhD and learn the research that way. I'm in Physiology now doing cerebro-vascular research which is related to stroke - that might be a path for you. you might also want to think more of neuroscience post-doc if you are interested in the brain tissue rather than the vasculature. Pathology might also be an option. Talk to the individual departments to see what is available depending on your individual interest - i'm sure that they would be willing to accomidate a MD who is interested in research - you're a hot comodity!
