The pattern of a7 GFP expression in the E18.5 cochlear structure undergoes significant remodeling as both sensory hair cells and the associated supporting cells complete their differentiation ( Fig. 2H and I). This includes a decrease of a7 GFP expression by OHCs and underlying Deiters' cells that progresses away from the inner hair cells and proceeds in a basal-to-apical direction (next section). This is coincident with the appearance of signal in Hensen's cells that are most proximal to the outer line of OHCs (returned to below). Ganglionic afferent fibers ending at the base of the inner hair cells are also detected (see subsequent sections). In the postnatal mouse, as shown in the P6 cochlear sensory structure ( Fig. 2J and K), the expression of a7 GFP becomes limited to Hensen's cells immediately adjacent to the most distal OHC. Cells of the spiral ligament also acquire a7 GFP expression, while the spiral prominence remains unchanged. In the SG, the expression of a7 GFP is well established and the projections from these labeled cells can be followed to the vicinity of the inner hair cells (IHC) where their terminals appear to surround the base of the inner hair cell (IHC; Fig. 2J and K). A summary diagram illustrating the expression of the a7 GFP during these major developmental stages is shown in Fig. 2L . Remodeling of a7 GFP in the cochlear structure after E16.5 is in a basal-to-apical direction