Rostral anterior cingulate connectivity in older adults with subthreshold depressive symptoms: A preliminary study

Subthreshold depressive symptoms are highly prevalent among older adults and are associated with numerous health risks including cognitive decline and decreased physical health. One brain region central to neuroanatomical models of depressive disorders is the anterior cingulate cortex (ACC). The rostral portion of the ACC-comprised of the pregenual ACC and subgenual ACC-is implicated in emotion control and reward processing. The goal of the current study was to examine how functional connectivity in subregions of the rostral ACC relate to depressive symptoms, measured by the Beck Depression Inventory-Second Edition, in an ethnically diverse sample of 28 community-dwelling older adults. Based on meta-analyses of previous studies in primarily young adults with clinical depression, we hypothesized that greater depressive symptoms would be associated with primarily increased resting-state functional connectivity from both the subgenual ACC and pregenual ACC to default mode network regions and the dorsolateral PFC. We instead found that higher depressive symptoms were associated with lower functional connectivity of the ACC to the dorsolateral PFC and regions within the default mode network, including from the subgenual ACC to the dorsolateral PFC and anterior cingulate and from the pregenual ACC to the middle cingulate gyrus. This preliminary study highlights brain alterations at subthreshold levels of depressive symptoms in older adults, which could serve as targets for interventions.

Anterior cingulate cortex grey matter volume abnormalities in adolescents with PTSD after childhood sexual abuse

Adverse childhood experiences (ACE) substantially increase the risk of later psychiatric and somatic pathology. While neurobiological factors are likely to play a mediating role, specific insights are lacking. The scarce neuroimaging studies in traumatised pediatric populations have provided inconsistent results, potentially due to the inclusion of different types of trauma. To further improve our understanding of the neurobiology of pediatric psychotrauma, this study seeks to investigate abnormalities in grey matter volume (GMV) in a homogeneous group of adolescents with posttraumatic stress disorder (PTSD) due to childhood sexual abuse (CSA) and the relationship between GMV and symptom severity. We performed a voxel based morphometry (VBM) analysis in 21 adolescents with CSA-related PTSD and 25 matched non-traumatised, non-clinical adolescents. Hippocampus, amygdala, anterior cingulate cortex (ACC), medial PFC (mPFC) and superior temporal gyrus (STG) were chosen as regions of interest (ROIs). Trauma symptomatology was measured with the Trauma Symptom Checklist for Children (TSCC) and dissociation symptoms with the Adolescent Dissociative Experiences Scale (A-DES). The ROI analysis showed that the CSA-related PTSD group had significant smaller volumes of the dorsal ACC as compared to healthy controls. However, no correlations were found between GMV and scores on the TSCC and A-DES. The smaller ACC volume is partly in line with previous studies in traumatised youth and is a consistent finding in traumatised adults. Taken together our results suggest that the dorsal ACC is implicated in the neurobiological sequelae of CSA, potentially associated with an altered evaluative processing of emotion, but not directly with PTSD severity.