Transplanted BMSCs are initially located in the injected site (left hemisphere). Gradual disappearance of photon emission during 7 days after injection on the injection site is noted. No migration is observed in control group (a). Experimental mice injected of cells 2 h (b) and 1 week (c) after MCAO show signals in infarction area (right hemisphere) after crossing the midline and subsequent increasing intensity over time.