Identification of lateral and medial entorhinal cortex at PCW 15 and 21. (a, b). Lateral (a) and medial (b) entorhinal cortex (LEC and MEC, respectively) identified on SATB2-stained section at PCW15. The inset in (b) is a higher power view of the MEC (#s indicate the same location). (c, d) LEC (c) and MEC (d) identified on SATB2-stained section at PCW21. The inset in (c) is a higher power view of the LEC (the arrows indicate the same location). SATB2 expression is seen in both layers 5 and 6 of the LEC including the olfactory part (ECo) (c) but only in layer 5 of the MEC (d). At both PCW 15 and 21, strong SATB2 expression is seen in layer 5 of the MEC and layers 2-3 of the presubiculum (PrS) and parasubiculum (PaS). Pu, putamen; AMY, amygdala; LGE and CGE, lateral and caudal ganglion eminence. Scale bar: 790 μm in (a) for all panels.