Alertness Related Network In Patients With Temporal Lobe Epilepsy: A Resting State Fmri Study Based On ICA

Objectives: Patients with TLE often suffer from congnitive impairment, for instance, working memory, attetion and excute function. However, little is known about the alertness function in patients with TLE. This study aimed to investigate the alteration of the alertness-related network in patients with right temporal lobe epilepsy(r TLE) and explore the functional mechanism of the cognitive impairment in alertness by using behavior test and resting-state functional magnetic resonance imaging(rs-f MRI).Methods: Twenty patients with r TLE and eighteen healthy controls were recruited in the present study. All participants took a neuropsychological test of attention network test(ANT), then underwent resting-state functional magnetic resonance imaging(rs-f MRI) scan. The alertness-related network were extracted by using multiple independent component analysis(MICA). Then the average Z-transformed connectivity maps were caculated using one-sample t-test in each group. Significant result maps of the two groups were combined to a binary mask. Subsequently, the intergroup connectivity differences was compared using two-sample t-test in the mask. The neuropsychological data were correlated to the the voxels which showed significant differences in FC in patients with r TLE.Results: 1、Patients with r TLE showed significant longer RT(644.91±72.63) than controls(591.65±83.89) in no cue condition(t =-2.07, p < 0.05). Significant differences were also observed in double cue condition(t =-2.28, p < 0.05) between patients(602.15±74.93) and controls(546.23±74.39). The alertness effect, however, showed no significant difference between patients and controls(t=-0.366,p=0.72).2、The alertness-related network extracted from the patients were similar to the controls, covering right dorsolateral prefrontal cortex, middle frontal gyrus, parietal lobe, part of temoral lobe, and left posterior lobe of the cerebellum(p < 0.05, Alphasim correction, cluster size > 85). Compared with the controls, patients with r TLE exhibited a decreased FC value in the right inferior parietal lobe(IPL) and angular gyrus(p < 0.05, Alphasim correction, cluster size > 42). In addition, increased FC was showed in the right inferior frontal gyrus, rolandic operculum, middle frontal gyrus, dorsolateral superior frontal gyrus, cuneus, superior occipital gyrus(p < 0.05, Alphasim correction, cluster size > 42).3、 The alertness effect were negatively correlated with the mean Z-value in right cuneus which showed increased FC(r=-0.556.p =0.013) in patients with r TLE.Conclusion: 1、Patients with r TLE show similar alertness-related network with controls, mainly covering right dorsolateral prefrontal cortex, middle frontal gyrus, parietal lobe, part of temoral lobe, and left posterior lobe of the cerebellum.2、Patients with r TLE showed longer RT in both no cue and double cue conditions, suggesting the capability loss in intrinsic and phasic alertness.3、The decreased FC of the right inferior parietal lobe and angular gyrus in patients with r TLE suggest the disruption of the alertness-related network and might cause the alertness impairment.4、The increase FC of brain regions in alertness-related network migh be a compensatory recruitment of cognitive functions in patients with r TLE.