Structural covariance, topological organization, and volumetric features of amygdala subnuclei in posttraumatic stress disorder

• Published in: NeuroImage clinical 2024-01, Vol.42, p.103619-103619, Article 103619
• Main Authors: Haris, Elizabeth M., Bryant, Richard A., Korgaonkar, Mayuresh S.
• Format: Article
• Language: English
• Subjects: Accessory-basal nucleus; Amygdala subnuclei; PTSD; Regular; Structural covariance
• ISSN: 2213-1582; 2213-1582
• DOI: 10.1016/j.nicl.2024.103619

•Functionally connected brain regions show high covariance in morphological measures.•Differences between subnuclei covariance profiles in both groups were observed.•No between-group differences in subnuclei covariance profiles were found.•This work highlights the merit of examining amygdala subnuclei in humans and PTSD.•Further work examining functional connectivity using high-field fMRI is necessary. The amygdala is divided into functional subnuclei which have been challenging to investigate due to functional magnetic resonance imaging (MRI) limitations in mapping small neural structures. Hence their role in the neurobiology of posttraumatic stress disorder (PTSD) remains poorly understood. Examination of covariance of structural MRI measures could be an alternate approach to circumvent this issue. T1-weighted anatomical scans from a 3 T scanner from non-trauma-exposed controls (NEC; n = 71, 75 % female) and PTSD participants (n = 67, 69 % female) were parcellated into 105 brain regions. Pearson’s r partial correlations were computed for three and nine bilateral amygdala subnuclei and every other brain region, corrected for age, sex, and total brain volume. Pairwise correlation comparisons were performed to examine subnuclei covariance profiles between-groups. Graph theory was employed to investigate subnuclei network topology. Volumetric measures were compared to investigate structural changes. We found differences between amygdala subnuclei in covariance with the hippocampus for both groups, and additionally with temporal brain regions for the PTSD group. Network topology demonstrated the importance of the right basal nucleus in facilitating network communication only in PTSD. There were no between-group differences for any of the three structural metrics. These findings are in line with previous work that has failed to find structural differences for amygdala subnuclei between PTSD and controls. However, differences between amygdala subnuclei covariance profiles observed in our study highlight the need to investigate amygdala subnuclei functional connectivity in PTSD using higher field strength fMRI for better spatial resolution.