Once thought to be simply permissive, mammalian BAF complexes have critical functions in multiple aspects of neural development. The specific BAF assemblies found in ES cells, neural progenitors and postmitotic neurons have non-redundant functions which stem from structural divergence within closely related homologous subunit families. The npBAF complex is essential for controlling the kinetics and mode of neural progenitor cell division; in particular, it regulates the generation of upper-layer cortical neurons which have co-emerged with the expansion of the SVZ in recent mammalian brain evolution (Aboitiz et al., 2003; Marin-Padilla, 1992). On the other hand, nBAF function is necessary for the mature phenotypes of postmitotic neurons such as the refinement of axons and dendrites, and for determining the finer subtypes of several classes of neurons including deep-layer cortical neurons and hippocampal neurons. Surprisingly, the conserved mechanism for transitioning from npBAF to nBAF is instructive for the neuronal fate even in unrelated lineages, and may be a universal determinant of the core neuronal identity. Furthermore, BAF is essential for the plasticity of the adult brain and contributes to hippocampal LTP as
