\"Changing Concepts in CNS Repair: From Stem Cell to Activity-Based Restoration Therapies\" - Part 2 - Dr. John McDonald, Director of International Center for Spinal Cord Injury, Kennedy Krieger Institute&Johns Hopkins University - Lecture given at Working 2 Walk Science Symposium, April 22, 2007 in Washington DC. cord, injury, spinal, unite2fightparalysis, working2walk