An exploratory study of resting-state functional connectivity of amygdala subregions in posttraumatic stress disorder following trauma in adulthood

Abstract

We carried out an exploratory study aimed at identifying differences in resting-state functional connectivity for the amygdala and its subregions, right and left basolateral, centromedial and superficial nuclei, in patients with Posttraumatic Stress Disorder (PTSD), relative to controls. The study included 10 participants with PTSD following trauma in adulthood (9 females), and 10 controls (9 females). The results suggest PTSD was associated with a decreased (negative) functional connectivity between the superficial amygdala and posterior brain regions relative to controls. The differences were observed between right superficial amygdala and right fusiform gyrus, and between left superficial amygdala and left lingual and left middle occipital gyri. The results suggest that among PTSD patients, the worse the PTSD symptoms, the lower the connectivity. The results corroborate the fMRI literature that shows PTSD is associated with weaker amygdala functional connectivity with areas of the brain involved in sensory and perceptual processes. The results also suggest that though the patients traumatic experience occured in adulthood, the presence of early traumatic experiences were associated with negative connectivity between the centromedial amygdala and sensory and perceptual regions. We argue that the understanding of the mechanisms of PTSD symptoms, its behaviors and the effects on quality of life of patients may benefit from the investigation of brain function that underpins sensory and perceptual symptoms associated with the disorder.

Figure 1

Areas of negative correlation between functional connectivity for left and right SFA and PCL-5 in the PTSD group. (A) Illustration of seeds, filled in pink (seed is magnified for better visualization); (B) overlays for the areas of the brain that showed significant association for the SFA, for PTSD PCL-5 scores (p < 0.05 corrected for multiple comparisons); (C) bar graphs show the values of the Z scores for connectivity between the regions shown in the overlays in (B). Standard error bars are shown for Z values.

Figure 2

Areas of negative correlation between functional connectivity for left CMA and CTQ in the PTSD group. (A) Illustration of seeds, filled in pink (seed is magnified for better visualization); (B) overlays for the areas of the brain that showed significant association for the CMA, for PTSD CTQ scores (p < 0.05 corrected for multiple comparisons); (C) the scatter plots on the right show the relationship between the connectivity scores for the CMA and the associated regions. I = Bilateral anterior cingulate cortex (ACC); II = Right middle frontal gyrus. III = Right angular gyrus; IV = Right supplementary motor area (SMA); R right, L left, CTQ Childhood Trauma Questionnaire—total score, PCL-5 Posttraumatic Checklist-5—total score.