Abnormalities of the default-mode network homogeneity and executive dysfunction in people with first-episode, treatment-naive left temporal lobe epilepsy

OBJECTIVE: Converging evidence has demonstrated that there is aberrant connectivity of the default-mode network (DMN) in left temporal lobe epilepsy (ITLE) yet changes in the network homogeneity (NH) of the DMN in people with first-episode, treatment-naive ITLE remains unclear. In this study, we used an NH method to investigate the NH of the DMN in people with first-episode, treatment-naive, ITLE, at rest. PATIENTS AND METHODS: We collected resting-state functional magnetic resonance imaging (rs-fMRI), and attention network test (ANT) data from 43 people with ITLE and 42we11matched, healthy control subjects. An NH approach was used to analyze the data. RESULTS: People with ITLE have decreased NH in the right inferior temporal gyrus (ITG) and the left middle temporal lobe (MTG), and increased NH in the bilateral precuneus (PCu) and right inferior parietal lobe (IPL), as compared with the controls. We also found that people with ITLE had a longer executive control reaction time (RT). No significant correlations were found between abnormal NH values and clinical variables in the subjects. CONCLUSIONS: These findings suggest that abnormal NH of the DMN exists in ITLE subjects and highlight the significance of the DMN in the pathophysiology of cognitive problems occurring in ITLE.

Automated summary

The study found abnormal network homogeneity in the DMN of patients with initial untreated ITLE, including decreased NH in the right ITG and left MTG, and increased NH in the bilateral PCu and right IPL. Patients with ITLE also exhibited longer executive control reaction times.