(A) Upper row: DiI tracing of the visual cortex axons at P9 (before pruning), sagittal sections. Branching point of the tract is shown. Lower row: visual cortex axons in adult mice after pruning period. Note significantly reduced number of axons continuing into pyramidal tract in WT (dashed arrow). (arrows - 2 branches of corticospinal visual axons). Maximum projections are shown. Scale bars: 200 μm. 