What resolves this contention: Whether mouse-to-primate differences in corticos…

What resolves this contention: Whether mouse-to-primate differences in corticospinal/PT architecture are present at the level of cell-type identity vs only at the level of late developmental wiring. The first paper shows that the cortico-motoneuronal connection is transiently present in mice (i.e., the wiring difference is developmental), while the cross-species transcriptomic atlas frames pyramidal-class differences as molecular/cell-type specializations. / Previously thought to be specific to higher primates, we identified transient CM connections in early postnatal mice, which are eventually eliminated by Sema6D-PlexA1 signaling.mutant mice maintain CM connections into adulthood and exhibit superior manual dexterity as compared with that of controls. / Despite the overall conservation, however, many species-dependent specializations are apparent, including differences in cell-type proportions, gene expression, DNA