Table 4.
Neuropsychological tests of working memory and reasoning
| Group | Medial OFC (n = 6) | Lateral OFC (n = 12) | No lesion (n = 54) | Kruskal–Wallis χ2 | Kruskal–Wallis P value | Mann–Whitney U | Mann–Whitney UP value | Significant between-group differences |
| Digit span forward | 6.83 (1.17) | 6.50 (0.91) | 6.68 (1.22) | 0.69 | 0.71 | n/a | n/a | None |
| Spatial span forward | 7.83 (2.99) | 10.90 (1.97) | 10.22 (2.70) | 4.06 | 0.13 | n/a | n/a | None |
| 1-Back errors | 3.67 (1.97) | 3.25 (2.38) | 2.57 (2.48) | 2.72 | 0.26 | n/a | n/a | None |
| 2-Back errors | 6.83 (1.94) | 4.75 (2.92) | 3.85 (2.39) | 9.46 | 0.00 | 40.50 | 0.00 | Medial OFC > no lesion |
| 3-Back errors | 8.00 (2.28) | 5.38 (1.30) | 4.68 (2.40) | 8.39 | 0.01 | 48.50 | 0.00 | Medial OFC > no lesion |
| 7.50 | 0.03 | Medial OFC > lateral OFC | ||||||
| Total errors for 1-, 2-, and 3-Back | 6.17 (2.71) | 4.46 (2.38) | 3.70 (2.56) | 13.94 | 0.00 | 710.00 | 0.00 | Medial OFC > no lesion |
| 128.00 | 0.02 | Medial OFC > lateral OFC | ||||||
| Letter–number sequencing | 9.17 (1.84) | 9.67 (2.31) | 11.04 (2.66) | 5.76 | 0.06 | n/a | n/a | None |
| Digit span backward | 5.00 (1.09) | 4.58 (0.79) | 4.96 (1.41) | 0.73 | 0.69 | n/a | n/a | None |
| Spatial span backward | 10.33 (1.37) | 11.60 (2.79) | 12.02 (3.12) | 1.34 | 0.51 | n/a | n/a | None |
| Arithmetic | 10.33 (2.73) | 10.50 (2.71) | 11.00 (2.25) | 0.62 | 0.73 | n/a | n/a | None |
| Matrix reasoning | 11.00 (2.97) | 11.90 (3.14) | 12.28 (2.94) | 1.07 | 0.59 | n/a | n/a | None |
Note: OFC, orbitofrontal cortex; n/a, not applicable. Means are presented with standard deviations in parentheses. Because the assumptions of parametric statistics were not satisfied (Supplementary Table 1, Supplementary Figs 1–22), nonparametric statistics were used to test for group effects and for the pairwise comparisons. Significant between-group differences were determined with the Mann–Whitney U test, P < 0.05.