Fig. 6

Extent of area where axon collaterals of a single SP cell distribute. Levels 1–4 in the ventral brain surface (a) correspond to the four levels in the coronal plane reconstructed from 5 serial sections (b). The axon collaterals of the SP-1 cell are distributed within areas interconnecting the outermost tips of proximal ends (dotted lines) and those of distal ends (chain lines) of the collaterals in each plane