Canli et al. 10.1073/pnas.0601674103. |
Fig. 4. Amygdala activation as a function of 5-HTTLPR genotype and life stress. (Left) Clusters represent voxels in which amygdala activation to neutral and to happy faces-fixation varied significantly as an interaction of life stress and 5-HTTLPR genotype. (Center and Right) Scatterplots of percent mean activation across the clusters shown in Left as a function of life stress for the "S Group" (n = 32) and "L Group" (n = 16), respectively.
Fig. 5. Hippocampal activation as a function of 5-HTTLPR genotype and life stress. (Left) Clusters represent voxels in hippocampus activation to emotional or neutral faces-fixation varied significantly as an interaction of life stress and 5-HTTLPR genotype. (Center and Right) Scatterplots of percent mean activation across the clusters shown in Left as a function of life stress for the S Group (n = 32) and L Group (n = 16), respectively.
Supporting Text
Characteristics of Genotype Groups
. For participants in the functional MRI (fMRI) and voxel-based morphometry (VBM study) (n = 48), two-sample t tests revealed no significant group differences between carriers of the 5-HTTLPR short variant ("S group," n = 32, 16 males) and individuals homozygous for the 5-HTTLPR long variant ("L group," n = 16, 10 males) with regard to age, mood scores, trait extraversion or neuroticism scores, or the number of life stress categories endorsed. There was a significant correlation between age and the number of life stress categories endorsed (r = 0.41, P = 0.004). Therefore, variance due to age was partialled out in all fMRI and VBM imaging analyses (see Methods). Nonparametric (Mann-Whitney U) tests showed no significant difference in the distribution of sex or ethnicity across both groups. For participants in the perfusion study (n = 21), two-sample t tests revealed no significant differences between the S group (n = 13, 7 males) and the L group (n = 8, 7 males) with regard to age, mood, and trait extraversion scores. The S group scored significantly higher in trait neuroticism [t(19) = 3.64, P < 0.005), lower in life stress experiences (t(19) = -2.67, P < 0.05), and higher in rumination (t(19) = 2.26, P < 0.05) than the L group. There was no significant correlation between age and the number of life stress categories endorsed. Nonparametric (Mann-Whitney U) tests showed no significant difference in the distribution of sex or ethnicity.