Figure 16.

Summary diagrams of the main findings of the study. The left diagram (A) illustrates in schematic fashion the overall LPMCd corticospinal projection to the cervical enlargement from case SDM57-FD, which gave rise to the most prominent CSP of all LPMCd experimental cases. The relative intensity of the projection to spinal cord laminae is indicated by line thickness and arrowhead size. Strong bilateral projections were found to the medial and ventral parts of lamina VII and lamina VIII which are considered major targets of Kuypers medial motor system (shaded in red) which largely influences proximal limb and axial movements. In addition, a strong projection was found to the lateral sectors of contralateral lamina VII which are considered major components of Kuypers “lateral motor system” (shaded in blue) which largely influences distal limb movements. The blue asterisk located within the dorsomedial region of lamina VII denotes an area of CSP terminal overlap amongst the M1 hand CSP of the lateral motor system, and LPMCd CSP of the medial motor system. The right diagram (B) illustrates the overall LPMCv corticospinal projection to the cervical enlargement from case SDM72-FD, which originated from the post-arcuate cortical region. As indicated by the thin lines representing the relative projections to Rexed’s laminae, this CSP was sparse compared to the more prominent LPMCd CSP shown on the left. The white area located in anterior to the dashed line on the cortical surface represents the cortex lining the posterior bank of the arcuate sulcus. The black asterisk on the cortical surface that is posterior to the post-arcuate region denotes cortex located on the convexity that did not project below C2.