Fig. 5. Interneuron subtype development in the cingulate gyrus.

(A to E) Many DCX⁺ cells in the neonatal cingulate cortex express GAD67 (A), and sub-populations also coexpress interneuron subtype markers: calbindin (CalB) (B), neuropeptide Y (NPY) (C), somatostatin (SST) (D), and calretinin (CalR) (E). DAPI, 4′,6-diamidino-2-phenylindole. Yellow arrows point to DCX⁺ cells that coexpress the indicated subtype markers. (F) Spatiotemporal distribution of interneuron subtypes from birth to 24 years. NPY⁺ and SST⁺ cells are located primarily in the white matter at birth but shift to the cortex over time. CalR⁺ and CalB⁺ are already expressed in cells throughout the cortex at all ages, but their number continues to increase during the first five postnatal months. (G) Stereological quantification of interneuron subtypes in the cingulate cortex from birth to 24 years. The number of NPY⁺, SST⁺, CalB⁺, and CalR⁺ cells increases between birth and 5 months, coinciding with the arrival of DCX⁺ cells in the cingulate cortex (see Fig. 3G). Scale bars, 50 μm [(A) to (E)], 2 mm [(F), 1 day to 6 years], 1 mm [(F), 24 years]. Directional axes: D, dorsal; L, lateral.