Altered default mode network connectivity in adolescents with post-traumatic stress disorder
Résumé
Post-traumatic stress disorder (PTSD) is characterized by intrusions, re-experiencing,
avoidance and hyperarousal. These symptoms might be linked to dysfunction in core neurocognitive
networks subserving self-referential mental processing (default mode network, DMN), detection of
salient stimuli (salience network, SN) and cognitive dysfunction (central executive network, CEN).
Resting state studies in adolescent PTSD are scarce and findings are inconsistent, probably due to
differences in patient symptom severity. Resting state brain activity was measured in 14 adolescents
with severe PTSD and 24 age-matched controls. Seed-based connectivity analyses were used to
examine connectivity between the DMN and the whole brain, including regions from other networks
(SN and CEN). The relationships of network properties with symptom dimensions (severity, anxiety
and depression) and episodic memory were also examined. Analyses revealed decreased within-DMN
connectivity (between PCC and occipital cortex) in patients compared to controls. Furthermore, within-
DMN connectivity (between PCC and hippocampus) correlated negatively with symptom dimensions
(severity and anxiety), while increased connectivity (DMN-SN and DMN-CEN) correlated positively
with episodic memory measures. These abnormal network properties found in adolescent PTSD
corroborate those previously reported in PTSD adults. Decreased within-DMN connectivity and
disrupted DMN-SN and DMN-CEN coupling could form the basis for intrusive trauma recollection and
impaired episodic autobiographical recall in PTSD.
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