Laminar and compartmental regulation of dendritic growth in mature cortex

Can dendrites grow in mature cortex? We used chronic in vivo imaging to follow pyramidal neurons before and after cortical deletion of the Pten tumor suppressor gene in mature mice. We found that Pten/mTOR signaling uniquely regulates the growth of layer 2/3 apical dendrites; no effects of gene deletion were observed on basal dendrites of these pyramidal neurons or along layer 5 apical dendrites.