Abnormal default-mode network activation in cirrhotic patients: a functional magnetic resonance imaging study

Abstract

Recently, increasing numbers of studies have demonstrated that, in humans, a default-mode functional network exists in the resting state. Abnormal default-mode network in various diseases has been reported; however, no report concerning hepatic cirrhosis has been published to date. To prospectively explore whether the resting-state network in patients with hepatic cirrhosis is abnormal or not, using functional magnetic resonance imaging (fMRI). 14 patients with hepatic cirrhosis (12 male, two female; 45+/-9 years) and 14 age- and gender-matched healthy volunteers (12 male, two female; 42+/-10 years) participated in a blocked-design fMRI study. A modified Stroop task with Chinese characters was used as the target stimulus. Statistical Parametric Mapping 99 software was employed to process the functional data. Individual maps and group data were generated for patients with hepatic cirrhosis and for healthy controls, respectively. Intergroup analysis between patients and healthy controls was also generated using the two-sample t-test model. Cluster analyses were done based on the group data, and an identical P value < or =0.01 with continuously connected voxels of no less than 10 was defined as significant deactivation. After fMRI scanning was complete, behavioral Stroop interference tests were performed on all subjects; reaction time and error number were recorded. Functionally, deactivation of the posterior cingulate cortex (PCC) and precuneus was absent when subjects performed the incongruous word-reading task; deactivation of the PCC, precuneus, and ventral medial prefrontal cortex was increased when they performed the incongruous color-naming task. The functional as well as behavioral data suggest that cirrhotic patients may have an abnormal deactivation mode. The absence of deactivation in the PCC and precuneus may be a sensitive rather than specific marker in patients with hepatic cirrhosis.