1. M. M. Merzenich, W. M. Jenkins, P. Johnston, C. Schreiner, W. M. Keck Center for Integrative Neurosciences and Coleman Laboratory, University of California, San Francisco, CA 94143-0732, USA.
2. S. L. Miller and P. Tallal, Center for Molecular and Behavioral Neuroscience, Rutgers University, 197 University Avenue, Newark, NJ 07102, USA.