Fig. 1.

Subjective classification of PCs in the six layers of somatosensory cortex of juvenile rats. The classification was performed simply based on the morphological features of the apical dendrites: three types in layer 2 (A), two types in layer 3 (B), three types in layer 4 (C), four types in layer 5 (D), and six types in layer 6 (E). Reconstructed with Neurolucida system (MBF Bioscience, USA) from biocytin-filled neurons in 300 μm thick rat brain slices, an example PC represented each PC type (L3_TPC:A had two example cells showing different axon branching patterns in layer 4). Those having axonal clusters across multiple columns had been largely severed (Boudewijns, Kleele et al. 2011), leaving many collateral cutting segments attached to a main axonal stem that projects down towards white matter. Note: apical dendrites in purple, basal dendrites and somata in red, axons in dark blue.