A Research Of Basal Ganglion-cortical Loop In Epilepsy With Generalized Tonic-clonic Seizures

Generalized tonic-clonic seizures(GTCS)is a subtype of Idiopathic Generalized Epilepsy(IGE),which physiological feature is abnormal discharge of neuronal activity.Previous studies have found abnormalities in the thalamic-cortical connection pathway in patients with GTCS,which indicates that the connection characteristics of the subcortical-cortical circuit are closely related to the pathogenesis of GTCS,but no research has fo-cused on the ”sub-pathways” of the thalamus-cortical circuit,especially the effect of basal ganglia cortical pathway on GTCS.Therefore,this article intends to build a white matter connection pathway from the basal ganglia to the cerebral cortex at multiple levels and examine its structural connections and microstructures in detail.To this end,we collected magnetic resonance data from 68 GTCS patients and 85 healthy subjects,and analyzed the basal ganglia-cortical circuit of GTCS from three lev-els.First,at the whole brain level,we conducted a tract-based spatial statistics(TBSS)analysis and found that the fractional anisotropy(FA)values of GTCS patients were sig-nificantly reduced in the corpus callosum,inferior and superior longitudinal fasciculus,cingulate gyrus,anterior(posterior)corona radiata,inferior fronto-occipital fasciculus and anterior thalamic radiation? the mean diffusivity(MD)values were significantly increased in the Genu of corpus callosum,right anterior corona radiata,right superior longitudinal fasciculus and inferior fronto-occipital fasciculus? the radial diffusivity(RD)values were significantly increased in the corpus callosum,anterior corona radiata,right superior lon-gitudinal fasciculus,and inferior fronto-occipital fasciculus.These abnormalities indicate that the brain white matter of GTCS patients has undergone diffuse changes in the whole brain.Secondly,at the circuit level,we refer to the cortex-striatum model of four paral-lel pathways improved by Lawrence and his colleagues,and construct a total of 8 basal ganglia-cortex connection pathways in the left and right hemispheres using probabilistic tracing methods.Two-sample t test found that compared with healthy subjects,the average FA value of the right putamen to right supplementary motor cortex pathway in GTCS pa-tients was significantly reduced,and the MD(RD)value was significantly increased,which may be related to the dyskinesia of GTCS patients? the mean MD(AD)value of the left caudate nucleus to left dorsolateral prefrontal cortex pathway is significantly increased,and the average MD(AD and RD)values of the bilateral caudate nucleus to bilateral ven-trolateral prefrontal cortex pathway were significantly increased,which may be related to abnormal discharge in the frontal lobe? the average FA(AD)value of the bilateral ventral striatum to bilateral orbital frontal cortex pathway was significantly reduced,and the RD value was significant increased,which may be related to atrophy of the orbital gyrus.Finally,at the specific fiber bundle level,we used deterministic tracing to construct6 basal ganglia-cortical cortex white matter streamlines,excluding the left and right ven-tral striatum-orbitofrontal cortex pathways,and along the fiber bundle statistical analysis method is used to analyze the streamlines.Multivariate analysis of variance found that all 6 basal ganglia-brain cortex white matter fiber streamlines had a locally significant difference in diffusion index.The significant differences in the different pathways are dif-ferent.On the fiber streamlines of the putamen-supplementary motor cortex,the local significance of the FA value of GTCS patients is reduced,and the local significance of the MD(AD and RD)is increased.The other four pathways all showed a local significant re-duction in FA values of GTCS patients.This result further indicates that there is a certain change in the local characteristics of the white matter microstructure of the basal ganglion cortex pathway in GTCS patients.In summary,the TBSS,probabilistic tracing,and determintric tracing were used to in-vestigate the basal ganglia cortical pathways of GTCS patients at different levels.From the whole brain to specific circuits and to specific fiber bundles,we found diffusion changes in the whole brain white matter of GTCS patients,and the basal ganglia cortical circuit showed local abnormal changes,which may reflect the structural basis of brain function abnormalities in GTCS patients such as motor,spatial,visual and affective.The changes in the white matter microstructure found in this study are helpful for further understanding of the abnormalities of cortical basal ganglia basal ganglion cortex loop in GTCS,and provide valuable information on the role of basal ganglia in the loop.