Functional connectivity of hippocampal subregions in PTSD: relations with symptoms

Abstract

BackgroundPosttraumatic stress disorder (PTSD) is associated with abnormal hippocampal activity; however, the functional connectivity (FC) of the hippocampus with other brain regions in PTSD and its relations with symptoms warrants further attention. We investigated subregional hippocampal FC in PTSD during a resting state compared with a trauma-exposed control (TEC) group. Based on extant research, we targeted the FCs of the anterior and posterior hippocampal subregions with the amygdala, medial prefrontal cortex (mPFC), and the posterior cingulate (PCC).MethodsResting-state functional magnetic resonance images were acquired from 11 individuals with PTSD and 13 trauma-exposed controls. Anterior and posterior hippocampal FC was compared between groups. Within the PTSD and TEC groups, subregional hippocampal FC was correlated with scores on the Clinician-Administered PTSD Scale (CAPS) at time of scan and 4 months post-scan.ResultsThose with PTSD had significantly greater FC compared with the TEC group between the left posterior hippocampus and the bilateral PCC (g’s > .96). Direct contrasts of the Fisher z-transformed coefficients indicated that the correlations between CAPS scores 4 months post scan and the FC between the left hippocampal head and the right PCC (z = − 2.07, p = .039) as well as the FC between the right hippocampal tail and the right mPFC (z = − 2.19, p = .029) were significantly greater in the PTSD group compared to the TEC group.ConclusionsThese results support between-group differences in posterior hippocampal FC and different relations with PTSD future symptoms, underscoring associations with the anterior and posterior hippocampus. These findings enrich our understanding of PTSD pathophysiology and provide support for future investigations of imaging biomarkers predictive of disease progression.

Hippocampal connectivity in the aftermath of acute social stress

“…Previous studies have largely focused on the hippocampus as a unitary structure (Dunkley et al, 2014; Logue et al, 2018). There is accumulating evidence to support the differential roles of the hippocampal subregions in PTSD symptoms and associated memory processes (Malivoire et al, 2018). Given the different structural and functional connectivities of hippocampal subregions, investigating hippocampal rsFC at a subregional level in the present study may help elucidate the functional neurobiology of PTSD.…”

The intersection between the oculomotor and hippocampal memory systems: empirical developments and clinical implications

“…145,202 Cognitive therapies Beyond the insights that measures of eye movements can bring to diagnostics, the manner by which visual exploration occurs may provide therapeutic benefits for mental health disorders, such as depression, anxiety, and, in particular, PTSD, for which decreases in hippocampal subfield volume 203 and altered patterns of hippocampal functional connectivity have been observed. 204 Eye movement desensitization and reprocessing (EMDR) is a treatment technique in which emotional or traumatic memories are recalled (such as in the case of PTSD), while lateral saccades are made. 205 Altering the pattern of visual exploration, as occurs in EMDR, may, in turn, alter the amount, vividness, and/or emotional valence of the details that are retrieved from memory, and thereby alleviate debilitating symptoms.…”

Is PTSD-Phenotype Associated with HPA-Axis Sensitivity? Feedback Inhibition and Other Modulating Factors of Glucocorticoid Signaling Dynamics

“…Furthermore, while changes in the ventral hippocampus may explain part of the picture, there are many other factors involved. Although it was alluded to in a study by Malivoire et al [ 100 ] that the “anterior hippocampus is a potentially superior biomarker compared to the posterior hippocampus”, regarding PTSD symptomology, the dorsal hippocampus, which corresponds to the posterior part of hippocampus in humans [ 74 ], is known to play a crucial role in learning, long-term memory storage, and recollection memory, through its connection with the default-mode network [ 75 , 76 , 77 , 78 , 79 , 80 , 81 ] and has been linked to PTSD both in humans and in rodents [ 62 , 101 , 102 ]. Elevated levels of GR in the dorsal hippocampus after a traumatic event have been demonstrated in the dorsal hippocampus in numerous studies [ 92 , 93 , 94 , 95 , 96 ], including our group [ 97 ].…”