Cerebellum Abnormalities in Idiopathic Generalized Epilepsy with Generalized Tonic-Clonic Seizures Revealed by Diffusion Tensor Imaging

Although there is increasing evidence suggesting that there may be subtle abnormalities in idiopathic generalized epilepsy (IGE) patients using modern neuroimaging techniques, most of these previous studies focused on the brain grey matter, leaving the underlying white matter abnormalities in IGE largely unknown, which baffles the treatment as well as the understanding of IGE. In this work, we adopted multiple methods from different levels based on diffusion tensor imaging (DTI) to analyze the white matter abnormalities in 14 young male IGE patients with generalized tonic-clonic seizures (GTCS) only, comparing with 29 age-matched male healthy controls. First, we performed a voxel-based analysis (VBA) of the fractional anisotropy (FA) images derived from DTI. Second, we used a tract-based spatial statistics (TBSS) method to explore the alterations within the white matter skeleton of the patients. Third, we adopted region-of-interest (ROI) analyses based on the findings of VBA and TBSS to further confirm abnormal brain regions in the patients. At last, considering the convergent evidences we found by VBA, TBSS and ROI analyses, a subsequent probabilistic fiber tractography study was performed to investigate the abnormal white matter connectivity in the patients. Significantly decreased FA values were consistently observed in the cerebellum of patients, providing fresh evidence and new clues for the important role of cerebellum in IGE with GTCS

Kinesin 3 and cytoplasmic dynein mediate interkinetic nuclear migration in neural stem cells

Radial glial progenitor cells exhibit bidirectional cell cycle-dependent nuclear oscillations. The purpose and underlying mechanism of this unusual 'interkinetic nuclear migration' are poorly understood. We investigated the basis for this behavior by live imaging of nuclei, centrosomes and microtubules in embryonic rat brain slices, coupled with the use of RNA interference (RNAi) and the myosin inhibitor blebbistatin. We found that nuclei migrated independent of centrosomes and unidirectionally away from or toward the ventricular surface along microtubules, which were uniformly oriented from the ventricular surface to the pial surface of the brain. RNAi directed against cytoplasmic dynein specifically inhibited nuclear movement toward the apical surface. An RNAi screen of kinesin genes identified Kif1a, a member of the kinesin-3 family, as the motor for basally directed nuclear movement. These observations provide direct evidence that kinesins are involved in nuclear migration and neurogenesis and suggest that a cell cycle-dependent switch between distinct microtubule motors drives interkinetic nuclear migration