Abnormal Functional And Structural Connectivity In Posterior Cingulate Cortex And Their Relationships With Alertness Function In Right Temporal Lobe Epilepsy

[Objective] To investigate the alterations of posterior cingulate cortex resting state functional and structural connectivity and their relationships with alertness function of right temporal lobe epilepsy(rTLE).[Methods] Seventeen rTLE patients and twenty-one healthy controls were invited to the study.All participants underwent an attention network test(ANT),and performed a resting state functional magnetic resonance imaging(fMRI)and diffusion tensor imaging(DTI)scan.We combined fMRI with DTI to investigate changes in functional and structural connectivity of posterior cingulate cortex in rTLE.Using correlation analysis method the relationship between functional and structural connectivity strength and the alertness performance was assessed.[Results] Reaction times of intrinsic and phasic alertness performance were significantly longer in rTLE patients(t=-2.771,-2.671;P=0.009,0.011).The fractional anisotropy(FA)was significantly lower in rTLE patients(t=-2.136,P=0.040).The temporal-pole-middle-right,left inferior temporal gyrus,frontal-superior-medial-left and right posterior cingulate cortex showeddeceased functional connectivity(FC)with the left posterior cingulate cortex in rTLE group(P<0.05).The temporal-pole-middle-right,right hippocampus,right parahippocampal gyrus and left posterior cingulate cortex showed deceased FC with the right posterior cingulate cortex in rTLE group(P<0.05).In rTLE group,the decreased FC of the left posterior cingulate cortex and frontal-superior-medial-left was significantly correlated with the alertness effect(r=-0.724,P=0.001);the decreased FC between the bilateral posterior cingulate cortex was significantly correlated with the intrinsic(r=-0.484,P=0.049)and phasic alertness performance(r=-0.51,P=0.035).[Conclusions] Our findings suggest the impairment of posterior cingulate cortex alertness functional networks exist in rTLE patients.The fasciculus of the right posterior cingulate cortex was damaged in rTLE patients.The decrease FC between the bilateral posterior cingulate cortex,as well as between frontal-superior-medial-left and the left posterior cingulate cortex may cause alertness functional impairment in rTLE patients.