Exploratory tests of volume differences of amygdala subnuclei
| Subnuclei of amygdala | Subfield volume, mm3, mean ± SE | F | ηp2* | Volume reduction, %† | p value (unadjusted) | |
|---|---|---|---|---|---|---|
| OCD (n = 81) | Control (n = 93) | |||||
| Left medial nucleus | 19 ± 1 | 21 ± 1 | 6.07 | 0.034 | −9.5 | 0.015 |
| Left cortical nucleus | 20 ± 0 | 22 ± 0 | 10.634 | 0.058 | −9.1 | 0.001‡ |
| Left paralaminar nucleus | 55 ± 1 | 54 ± 1 | 0.713 | 0.004 | 1.9 | 0.40 |
| Left anterior amygdaloid area | 55 ± 1 | 55 ± 1 | 0.088 | 0.001 | 0.0 | 0.77 |
| Left corticoamygdaloid transition | 189 ± 3 | 188 ± 2 | 0.019 | 0.000 | 0.5 | 0.89 |
| Right medial nucleus | 22 ± 1 | 26 ± 1 | 19.43 | 0.101 | −15.4 | < 0.001‡ |
| Right cortical nucleus | 22 ± 0 | 26 ± 0 | 36.582 | 0.175 | −15.4 | < 0.001‡ |
| Right paralaminar nucleus | 55 ± 1 | 55 ± 1 | 0.004 | 0.000 | 0.0 | 0.95 |
| Right anterior amygdaloid area | 59 ± 1 | 61 ± 1 | 0.628 | 0.004 | −3.3 | 0.43 |
| Right corticoamygdaloid transition | 193 ± 3 | 198 ± 2 | 1.808 | 0.010 | −2.5 | 0.18 |
OCD = obsessive–compulsive disorder; SE = standard error.
↵* 0.01 indicates small effect size, 0.06 indicates medium effect size, and 0.14 indicates large effect size.
↵† Percent volume reduction was calculated as (adjusted mean volume of patients with OCD) – (adjusted mean volume of healthy controls) / [adjusted mean volume of healthy controls] × 100%.
↵‡ Significance after Bonferroni correction.