Fig. 1.

A single representative isolated adult flexor digitorum brevis (FDB) muscle fiber cultured on a laminin-coated cover slip in serum-containing media. Transmitted light images of the same fiber were taken 1 day (A), 3 days (B), 5 days (C), and 7 days (D) after plating. The images show the gradual transition from the adult fiber appearance to a myotube-like morphology, including branches and fine projections. The culture was returned to the tissue culture incubator for 2-day intervals between acquisitions of successive images. Scale bar = 0.1 mm.