The generation and properties of human cortical organoids as a disease model for malformations of cortical development

As three-dimensional“organ-like”aggregates,human cortical organoids have emerged as powerful models for studying human brain evolution and brain disorders with unique advantages of humanspecificity,fidelity and manipulation.Human cortical organoids derived from human pluripotent stem cells can elaborately replicate many of the key properties of human cortical development at the molecular,cellular,structural,and functional levels,including the anatomy,functional neural network,and interaction among different brain regions,thus facilitating the discovery of brain development and evolution.In addition to studying the neuro-electrophysiological features of brain cortex development,human cortical organoids have been widely used to mimic the pathophysiological features of cortical-related disease,especially in mimicking malformations of cortical development,thus revealing pathological mechanism and identifying effective drugs.In this review,we provide an overview of the generation of human cortical organoids and the properties of recapitulated cortical development and further outline their applications in modeling malformations of cortical development including pathological phenotype,underlying mechanisms and rescue strategies.

The molecular genetics of PI3K/PTEN/AKT/mTOR pathway in the malformations of cortical development

Malformations of cortical development(MCD)are a group of developmental disorders characterized by abnormal cortical structures caused by genetic or harmful environmental factors.Many kinds of MCD are caused by genetic variation.MCD is the common cause of intellectual disability and intractable epilepsy.With rapid advances in imaging and sequencing technologies,the diagnostic rate of MCD has been increasing,and many potential genes causing MCD have been successively identified.However,the high genetic heterogeneity of MCD makes it challenging to understand the molecular pathogenesis of MCD and to identify effective targeted drugs.Thus,in this review,we outline important events of cortical development.Then we illustrate the progress of molecular genetic studies about MCD focusing on the PI3K/PTEN/AKT/mTOR pathway.Finally,we briefly discuss the diagnostic methods,disease models,and therapeutic strategies for MCD.The information will facilitate further research on MCD.Understanding the role of the PI3K/PTEN/AKT/mTOR pathway in MCD could lead to a novel strategy for treating MCD-related diseases.

Pure Salivatory Seizures Secondary to a Subtle Malformation of the Right Parietal Cortex

Background: Salivatory seizures are a singularly rare condition, which can occur both in idiopathic and symptomatic epilepsies. Objectives: To describe and discuss the case of an adolescent patient with sleep-triggered “pure” salivatory seizures associated with a subtle cortical malformation of the right parietal cortex. Case report: Herein, we report a 17-year-old female who started to present salivatory paroxysms, which occasionally secondarily generalized, shortly after falling asleep, at the age of eight years. Video-electroencephalographic monitoring with scalp electrodes failed to show any epileptiform activity during the several recorded clinical events. Brain MRI and curvilinear reconstruction revealed, in the three orthogonal planes, a subtle cortical thickening, limited to a single gyrus in the right parietal cortex, suggestive of a focal cortical malformation. After antiepileptic drug therapy was optimized, the patient became seizure-free. Conclusion: An epilepsy diagnosis should be pursued in patients presenting isolated, paroxysmal hypersalivation, despite possible negative scalp EEG studies.