[1] St Louis Univ, Biol, St Louis, MO 63103 USA
[2] Univ Washington, Ophthalmol, Seattle, WA 98195 USA
[3] Univ Washington, Neurosci Grad Program, Seattle, WA 98195 USA
[4] Univ Texas Hlth Sci Ctr Houston, Neurobiol & Anat, Houston, TX 77030 USA
[5] Univ Utah, John A Moran Eye Ctr, Salt Lake City, UT 84112 USA