GAD65-containing neurons in a coronal section of the developing hippocampal formation at E20. GAD65-containing cell bodies are quite prominent throughout the hippocampal and dentate marginal zones (hMZ and dMZ), with many positive neurons occupying positions immediately adjacent to the principal cell body layers. This pattern of cell body localization is similar to the pattern of GAD67-containing neurons at E20 (compare with Fig. 2A). Very few labeled cells are detected within the pyramidal (P) and granule (G) cell layers. Scale bar, 50 μm.