Figure 1.

The laminar position of cortical interneurons is inverted in Dab1 mutant mice. A–D, Confocal microscopic reconstructions of the cerebral cortex of wild-type (A and C) and Dab1 mutant (B and D) mice stained for BrdU (red) and GABA (green) after injection of BrdU at E12 (A and B) or E15 (C and D). A, B, Early-born cortical interneurons (BrdU+/GABA+) acquire deep cortical positions in control mice (arrows), whereas they occupy superficial positions in Dab1 mutants (open arrowheads). C, D, Late-born interneurons (BrdU+/GABA+) populate mostly superficial layers (arrows) in wild-type mice, although a few also occupy deep layers (solid arrowhead). In Dab1 mutants, the majority of late-born interneurons occupy deep positions (open arrowheads), although some populate superficial layers (arrows). Numbers identify bins for quantification. E, F, Binned quantifications of the distribution of E12 (E) and E15 (F) interneurons in the cerebral cortex of wild-type (black bars) and Dab1 mutant (gray bars) mice (average + SEM). The width of the cortex proper (layers 1–6) was divided into 10 equal bins for laminar distribution analysis, with bin 1 at the top (marginal zone) and bin 10 at the bottom (white matter). Scale bar, 100 μm.