Figure 5.

Schematic depiction of dendritic development in wild-type and fragile X knockout mouse somatosensory whisker barrel cortex. In normal development in the wild type, dendrites initially extend both toward the interior hollow of the dendrite and toward the exterior septae region. As development progresses, hollow-oriented dendrites proliferate, while outwardly oriented dendrites regress. In the knockout mouse, the hollow-oriented dendrites proliferate normally, but the outwardly oriented dendrites exhibit impaired regression. P 0, postnatal day 0. Data are from Galvez et al. (R. Galvez, A. R. Gopal, and W.T.G., unpublished work).