Aleration Of Functional Connectivity Within Visuospatial Working Memory-related Brain Network In Patients With Right Temporal Lobe Epilepsy: A Resting State Fmri Study

【Purpose】: This study aimed to investigate the resting state brainnetwork related to visuospatial working memory (VSWM) in patients withright temporal lobe epilepsy (rTLE). The functional mechanism underlying thecognitive impairment in VSWM was also determined.【Method】: Fifteen patients with rTLE and16healthy controls matchedfor age, gender and handedness underwent a6min resting-state functionalMRI session and a neuropsychological test of VSWM_Nback. TheVSWM-related brain network at rest was extracted using multiple independentcomponent analysis, the spatial distribution and the functional connectivity(FC) parameters of the cerebral network are compared between groups.Behavioural data were subsequently correlated with the mean Z-value invoxels showing significant FC difference during inter-group comparison.【Results】: The distribution of the VSWM-related resting state network(RSN) in the rTLE group was virtually consistent with that in the healthycontrols. The distribution involved the dorsolateral prefrontal lobe and parietallobe in the right hemisphere and the partial inferior parietal lobe and posteriorlobe of the cerebellum in the left hemisphere (P <0.05, Alphasim corrected).Between-group differences suggest that the rTLE group had a decreased FCwithin the right superior frontal lobe (BA8area), right middle frontal lobe andright ventromedial prefrontal lobe compared with the controls (P <0.05, Alphasim corrected). The regions of increased FC in rTLE were localisedwithin the right superior frontal lobe (BA11area), right superior parietal lobeand left posterior lobe of the cerebellum (P <0.05, Alphasim corrected).Moreover, rTLE patients performed worse than controls in the VSWM Nbacktest and there were negative correlations between ACCmeanRT(2-back) andthe mean Z-value in the voxels showing decreased or increased FC in rTLE(P<0.05).【Conclusion】:(1) The VSWM related network in normal people ismainly consist of right frontal-parietal brain regions, left inferior parietal lobeand partial posterior lobe of cerebellum, suggesting the VSWM is a cognitivesystem with multiple regions and multiple functions operating in common.(2)The integrity of the VSWM related network at rest is altered in patients withtemporal lobe epilepsy.(3) The alteration of the VSWM related network atrest in rTLE patients might be the reason leading to their VSWM cognitivedeficit.(4) rTLE patients might compensate the damaged memory function byenlarging the FC within the ipsilateral cerebral network.