Cover photograph (Copyright © 2002, American Society for Microbiology. All Rights Reserved.): Localization of measles virus (MV) proteins in infected pyramidal neurons of rat hippocampal slice cultures. Shown is a three-dimensional reconstitution of a confocal scanning micrograph of a CA3 pyramidal cell from a slice infected with MV expressing enhanced green fluorescent protein (EGFP). The MV matrix protein (M) localized within the soma and dendrites is evident, having been captured by monoclonal anti-M antibody and labeled with Texas Red (resulting in a yellow color due to the intracellular localization of both EGFP and M protein). The transmission of infection to this part of the hippocampus has been shown to occur in a polarized fashion, i.e., retrograde across synapses. (See related article on p. 5720.)