Mapping neocortical volume. A. Likelihood ratio statistic (LRS) scores for neocortical volume across the entire genome. The x-axis represents the physical map of the chromosome; the y-axis and thick blue line provide the LRS of the association between the trait and the genotypes of markers. The two horizontal lines are the suggestive (blue) and significance (red) thresholds computed using 1000 permutations. There are QTLs (red arrows) on the distal end of Chr 6 and the proximal end of Chr 11. B. QTLs for residual neocortical volume (regressing out the effects of age, sex, plane of section, epoch, and non-neocortical brain weight) are identical to those seen in A, but with higher LRS scores. C. LRS map of all of Chr 6 (left) and Chr 11 (right) where the peak LRS score can be seen. Orange lines on x-axis represent high density SNP map. Discontinuous track along the top are the genes on this chromosome. D. A 10 Mb interval bordering the QTL on Chr 6 (left) and Chr 11 (right).