Figure 4.

Embryonic head cross-section provides a comprehensive view of placodal development. Time-lapse imaging of a cranial slice allows direct visualization of placode formation and morphogenesis through time in one field of view, from (1) the birth of placodal neurons in the ectoderm, (2) delamination of placodal neurons, and (3) maturation and aggregation of placodal neurons into ganglia in the mesenchyme. Imaging data reveal dynamic changes in placodal cell processes and morphology throughout gangliogenesis.