Fig. 11.

Principal corticocortical projections to area 4δ. We illustrate the principal connections from selected frontoparietal areas and from cingulate cortex to area 4δc. Only those projections quantified in Table 5 are presented. For comparison, we also present the principal inputs to area 6iffu as determined in a previous publication (Nakajima et al. 2019). In each block, the color indicates hindlimb (red) and forelimb (blue) representations in each of the indicated cortical areas in which somatotopy has been established. Note that for areas 5b, 4δc, and 4δr, we use gradations of blue and red to indicate that somatotopy is not as well developed as in M1 and S1. The direction and the thickness of the arrows gives an approximation of the relative strength of different connections and are based on our own observations (Table 5) as well as those of Ghosh (1997a).