A, FLICA labeling in the whole-mounted brain of a larval lamprey at 2 weeks post-transection. B, The fluorescent intensity of FLICA labeling was greatly reduced by pre-incubation with the unlabeled caspase inhibitor Z-VAD-FMK in the larval lamprey at 2 weeks post-transection. C and D, Higher maginification images from A and B. E, Effect of pre-incubation with unlabeled caspase inhibitor Z-VAD-FMK on intensity of FLICA labeling (means + SD). Pre-incubation reduced the intensity of FLICA labeling approximately 50% (p<0.0001, n=11 for FLICA labeling, n=20 for Z-VAD-FMK with FLICA labeling). Scale bar: 100 μm.