Neocortical Expansion Due to Increased Proliferation of Basal Progenitors Is Linked to Changes in Their Morphology

？ Basal progenitors (BPs) in the human neocortex have six distinct morphotypes ？ Increasing BP proliferative capacity is correlated with increasing BP process numbers ？ Membrane-bound PALMD is required for and sufficient to increase BP processes ？ Induction of BP processes by PALMD promotes BP proliferation via integrin signalin