Fig. 5.

Colocalizations of doublecortin (DCX) and polysialylated neural cell adhesion molecule (PSA-NCAM) (A–E), neuron-specific nuclear protein (NeuN) (F–J), γ-aminobutyric acid (GABA) (K–M) and glutamic acid decarboxylase (GAD)-67 (O–R). Bisbenzimide counterstain (blue) is included in some panels. Images are from the entorhinal (A, B, I, J) and temporal areas of young adult animals, including sulcal banks where the cortex is sectioned tangentially (C–E) or obliquely (F). DCX+ cells exhibit almost a complete colocalization with PSA-NCAM (A–E), although the latter labeling is faint in large cells with reduced DCX reactivity (white arrowheads, A, B). Note that labeled cells may appose to each other forming clusters (white arrows). NeuN is expressed in larger (white arrows, G, H) but not small (black arrowheads, G–J) cells (F–J). Panel F shows changes of relative reactivities of DCX verse NeuN among a cohort of cells with varying size and neuritic complexity. DCX levels increase, peak and then decline as cells become larger with thicker dendrites, in parallel with emergence and increase of NeuN (from artificially defined stages 1 to 8). Two tightly apposed DCX+ cells (framed) in G and H exhibit dramatic difference in size and NeuN colocalization (with and without). Panels I and J show two examples of large clusters, one with cells migrating inwardly along a chain (J). GABA labeling appears absent in the small DCX+ cells (black arrowheads), but is clear in medium to large cells with distinct (double white arrows) to reduced (single white arrow) DCX levels, including those localized deeper to the cellular band in layers II/III (K–M). GAD67 labeling appears only in medium or large cells with reduced DCX levels in layers II/III (O, P) or deeper locations (Q, R). Scale bar = 50 μm in A applying to other panels, equal to 25 μm in the bottom boxes in G and H.