Target fibers can be seen in neurogenic atrophy. They appear as a centrally located dark staining patch on Gomori's modified trichrome but are best demonstrated by NADH-TR preparations as illustrated here. Characteristically, there is a pale core with no NADH-TR activity, rimmed by a darkly stained ring and surrounded by a more normal staining peripheral zone. Substantial variation in fiber diameter with atrophic and hypertrophic fibers typical for neurogenic atrophy is also present in this specimen; these features are usually not seen in central core disease.