Location and extent of unilateral cervical lesion in Mks 1–3. Location and extent of the unilateral lesion (grey area), performed at C7/C8 level in Mk1, Mk2 and Mk3, shown on a reconstructed frontal view of cervical cord (three rightmost panels). The inset on the left is a frontal section of the macaque monkey cervical cord showing the distribution of CS axons (black dots) as a result of injection of the anterograde tracer Biotinylated Dextran Amine (BDA) in the right motor cortex (as recently reported in ). The CS axons originating from the right hemisphere are distributed mainly in the left dorsolateral funiculus (90–95%), representing the decussated CS tract. The uncrossed CS tract (5–10%) comprises, on the right side, axons in the dorsolateral funiculus and in the ventral funiculus. Scale bars = 2 mm.