Brain network mechanism of working memory impairment in temporal lobe epilepsy: A resting-state fMRI study

Background: Most temporal lobe epilepsy patients accompany with working memory impairment, but the specific brain network mechanism is still unclear. In this study, we used independent component analysis (ICA) to segregate resting-state magnetic resonance imaging (MRI) and evaluated the brain network mechanism of working memory impairment in patients with temporal lobe epilepsy (TLE). Methods: : Resting-state functional magnetic resonance imaging (fMRI) data were collected from 38 patients with TLE and 20 healthy controls. TLE patients were divided into a disordered working memory group (TLE-DWM) and a non-disordered working memory group (TLE-NWM) according to their performance in a delayed matching-to-sample (DMS) working memory task. We used ICA to extract the default mode network (DMN), left central executive network (LCEN), right central executive network (RCEN), and salience network (SN), and to compare the functional connection changes between the four groups. Pearson correlation analysis was used to calculate the correlation between connection strength and working memory performance. Results: : intra-network, inter-network, DMS working test, pearson correlation.We found that the connectivity of the right inferior parietal lobe and precuneus lobe in the control and TLE-NWM groups was higher than that in the TLE-DWM group. The connectivity of the posterior cingulate gyrus in the control and TLE-NWM groups was higher than that in the TLE-DWM group. The connection of the putamen in the control and TLE-NWM groups was greater than that in the TLE-DWM group. The Z values of the TLE-DWM, TLE-NWM, and control groups in the posterior cingulate gyrus of the LCEN network were negatively correlated with response time (RT). Conclusion: This study demonstrated that the functional connectivity of right inferior lobe, left precuneus lobe, left posterior cingulate gyrus, left putamen, and DMN-LECN network was decreased in TLE-DWM individuals, indicating that these network alternations correlated with the working memory impairment. In addition, we also found the connectivity of the posterior cingulate gyrus in LECN was negatively correlated with RT, which suggested that posterior cingulate gyrus was associated with the performance of working memory.