Figure 3.

Analysis of layer 2/3 pyramidal cell morphometry in postnatal day 40 wild type (WT) versus Emx1^cre/Met^fx/fx (−/−) anterior cingulate cortex (ACC). A: Representative fluorescence micrograph of lucifer yellow immunoreactivity in microinjected pyramidal cells in both left and right anterior cingulate cortex in a coronal brain section. Injections of Layer 2/3 pyramidal cells (arrow, left hemisphere) were highly reproducible across animals in terms of radial distance from the pial surface/median fissure (mf). The dashed lines represent the anatomical boundary between ACC and primary motor cortex (M1) in each hemisphere. B: Representative Neurolucida traces of layer 2/3 WT and −/− ACC pyramidal neurons. The neurons depicted have dendritic arbor morphometries approximate to the mean values of their genotypic group. C–H: Dendritic morphometry summary statistics. Though the average total dendritic arbor lengths are statistically equivalent (C), −/− arbors exhibit increased dendritic length proximal to, but decreased dendritic length distal to, the cell body (D). Sholl analysis shows that changes in branching complexity in −/− arbors mirror changes in dendritic length as a function of distance from the cell body (E). Subcomponent analyses for arbor length indicate that proximal increases in −/− arbor length reflect changes in the basal arbor (F), while the apical arbor (G) accounts for decreases in distal arbor length. Three-dimensional convex hull analysis reveals a strong trend toward reduced arbor volume in −/− layer 2/3 pyramidal neurons (H), consistent with reduced apical arbor length distal to the cell body. Scale bar = 275 μM for A and 100 μM for B. **p ≤ 0.01, *p ≤ 0.05, ^#p ≤ 0.1.