Altered functional connectivity within default mode network after rupture of anterior communicating artery aneurysm

Abstract

BackgroundRupture of anterior communicating artery (ACoA) aneurysm often leads to cognitive impairment, especially memory complaints. The medial superior frontal gyrus (SFGmed), a node of the default mode network (DMN), has been extensively revealed to participate in various cognitive processes. However, the functional connectivity (FC) characteristics of SFGmed and its relationship with cognitive performance remain unknown after the rupture of the ACoA aneurysm.MethodsResting-state functional MRI (fMRI) and cognitive assessment were acquired in 27 eligible patients and 20 controls. Seed-based FC between unilateral SFGmed and the rest of the brain was calculated separately, and then compared their intensity differences between the two groups. Furthermore, we analyzed the correlation between abnormal FC and cognitive function in patients with ruptured ACoA aneurysm.ResultsCognitive impairment was confirmed in 51.9% of the patients. Compared with the controls, patients suffering from ruptured ACoA aneurysm exhibited a similar FC decline between each side of SFGmed and predominant nodes within DMN, including the precuneus, angular gyrus, cingulate cortex, left hippocampus, left amygdala, left temporal pole (TPO), and left medial orbitofrontal cortex (mOFC). Besides, significantly decreased FC of left SFGmed and left insula, right middle temporal gyrus (MTG), as well as right mOFC, were also found. In addition, only enhanced insular connectivity with right SFGmed was determined, whereas increased FC of the left SFGmed was not observed. Correlation analyses showed that lower total cognitive performance or stronger subjective memory complaints were related to reduced connectivity in the SFGmed and several cortical regions such as the angular gyrus and middle cingulate cortex (MCC).ConclusionOur results suggest that patients with ruptured ACoA aneurysm exist long-term cognitive impairment and intrinsic hypoconnectivity of cognition-related brain regions within DMN. Deactivation of DMN may be a potential neural mechanism leading to cognitive deficits in these patients.

Features of cortical morphology in aneurysmal subarachnoid hemorrhage

“…In this study, nearly onethird of patients (21/68) had a history of AComA aneurysm rupture, which may be a crucial contributing factor leading to medial frontal cortex damage. In our recently published study 26 , seed-based resting-state functional connectivity analysis revealed that hypoconnectivity of medial superior frontal gyrus in patients with ruptured AComA aneurysm was associated with their memory loss. Structural gray matter atrophy in superiorfrontal gyrus of the present study provides an important structural basis for abovementioned aberrant intrinsic connectivity.…”

Neurobehavioral Impairments Predict Specific Cerebral Damage in Rat Model of Subarachnoid Hemorrhage

“…However, anxiety is a common feature in patients who survive SAH [54], and clinical studies have demonstrated dysfunction in the amygdala in SAH patients [55]. This reinforces that behavioral assessments of anxiety-like behavior may be sensitive and speci c for detecting dysfunction and damage affecting the amygdala and may provide a useful tool for predicting the development of damage in the amygdala.…”

“…Depression is a common and disabling condition that often occurs after SAH [56], and our study found that measures of depression-like behavior are both sensitive and speci c for predicting damage in associated cerebral regions. Although the anatomic correlates of post-SAH depression are not well understood, studies in patients with SAH have demonstrated dysfunction in the cingulate cortex, which has also been observed in preclinical and clinical studies of depression [55,57,58]. Additionally, the thalamus and hypothalamus have been implicated in depression in humans [59,60], although their contribution to depressive behavior in SAH is less clear.…”