Time-lapse imaging of fluorescently labeled live cells in the embryonic mammalian forebrain.

Time-lapse imaging of fluorescently labeled cells in organotypic slice culture provides a unique window through which to view development of the embryonic forebrain. The live imaging approach allows investigators to directly observe and record neurogenic and gliogenic divisions in the developing forebrain, to record the proliferative behavior of embryonic precursor cells, and to track newborn cells as they migrate from the proliferative zones to their final destination. This approach allows for identification and characterization of embryonic precursor cells, permits the physiological and immunohistochemical characterization of the fluorescent cells under study, and presents an opportunity to test hypotheses about mechanisms that guide developmental processes in the forebrain. This article describes a protocol for time-lapse imaging of fluorescently labeled cells in the embryonic forebrain of organotypic slice cultures. The procedure does not require prohibitively expensive on-stage incubation systems, and can yield reliable data from embryonic slices for up to 1 wk. Tracking the movement of labeled cells in slice culture is relatively straightforward in those cases in which there are few labeled cells. Although this approach is time intensive, it provides beautifully detailed images that reveal morphological and functional data from labeled cells over time, and can yield a significant amount of data from each cell.