Cell type-specific dendritic polarity in the absence of spatially organized external cues.

Pyramidal neurons of the hippocampus and cortex have polarized dendritic arbors, but little is known about the cellular mechanisms distinguishing apical and basal dendrites. We used morphometric analysis and time lapse imaging of cultured hippocampal neurons to show that glutamatergic neurons develop progressive dendritic asymmetry in the absence of polarized extrinsic cues. Thus, pyramidal neurons have a cellular program for polarized dendrite growth independent of tissue microenvironment.