Morphology of the four L1 IN populations. Morphology of the four L1 IN populations. A, Representative reconstructions of each of the four L1 IN populations. Soma is shown in black, axon in red, dendrites in blue, and L1 borders in gray. Inset shows the magnified somatodendritic profile of the α7 and VIP cells showing that the α7 cell is multipolar and the VIP cell is bipolar. B1, Bar plot showing a greater number of primary dendrites for α7 cells compared with VIP cells (p = 0.0047, Mann–Whitney U test). B2, Bar plot showing larger soma size of α7 cells compared with VIP cells (p = 0.0012, Mann–Whitney U test). C1, Bar plot showing greater proportion of the axon in L1a of canopy cells compared with NGFCs (p = 0.00033, Mann–Whitney U test). C2, Bar plot showing smaller proportion of axon in L1b of canopy cells compared with NGFCs (p = 0.00058, Mann–Whitney U test). Note that NGFCs have approximately the same proportion of their axon in L1a and L1b. D, Normalized distribution of axon for NGFCs (green) and canopy cells (orange) across L1a (pia to L1 midline), L1b (L1 midline to L1/2 border), and L2. Line indicates mean and shaded area indicates SEM. All bar plots show the mean value with SEM indicated by black bar; open circles show individual values. All morphological analysis was performed on reconstructed cells; n = 8 for NGFCs, n = 9 for canopy cells, n = 7 for α7 cells, and n = 6 for VIP cells. ** p < 0.01. *** p < 0.001. Benjamin Schuman et al. J. Neurosci. 2019;39:125-139 ©2019 by Society for Neuroscience