(A and B) Top two principal components for mPFC samples in (A) postnatal ages 0 M to 48 M and (B) prenatal ages E40–E120. Age and layer of each sample are depicted by marker shape and color, respectively. Shown are postnatal layers L2 (blue), L3 (green), L4 (black), L5 (purple), and L6 (red) and prenatal layers VZ (purple), SZ/IFZ (cyan), IZ/OFZ (orange), SP (blue), L5/L6/CPi (green), L2/L3/CPo (red), and MZ (black). Samples obtained from a given age and layer are relatively homogeneous in their rates of transcription.