Pediatric Brain Maturation and Migration Disorders

Modeling forebrain regional development and connectivity by human brain organoids

The forebrain is one of the most important brain structures for modern human existence, which houses the uniquely sophisticated social and cognitive functions that distinguish our species. Therefore, modeling the forebrain development by using human cells is especially critical for our understanding of the intricacies of human development and devising treatments for related diseases. Recent advancements in brain organoid fields have offered unprecedented tools to investigate forebrain development from studies on specific regions to exploring tract formation and connectivity between different regions of the forebrain. In this review, we discuss the developmental biology of the forebrain and diverse methods for modeling its development by using organoids.

MRI Evaluation of Corpus Callosum Malformation and Associated Anomalies: A Retrospective Cross-Sectional Study

Objective This study aims to evaluate the MRI morphology of corpus callosum malformations and the associated anomalies frequently observed in a tertiary care center in northern India. Methods We conducted a retrospective cross-sectional study using MRI reports, images, and clinical records from January 2020 to July 2024. A total of 19 patients with corpus callosum agenesis or hypoplasia were identified, with 17 patients included after excluding those with incomplete records. We analyzed MRI findings for agenesis type (complete or partial), commissural abnormalities, midline anomalies, cortical abnormalities, and posterior fossa abnormalities. Statistical analysis was performed using chi-square tests to compare associations between complete and partial agenesis. Results Of the 17 patients, 52.9% had complete agenesis and 47.1% had partial agenesis. Complete agenesis was associated with higher rates of commissural involvement (44.4% vs. 12.5%), midline anomalies (22.2% vs. 0%), and Probst bundle formation (88.9% vs. 37.5%). Ventricular distortion was more common in complete agenesis (88.9% vs. 40%), and cortical malformations were also more prevalent (44.4% vs. 12.5%). Other anomalies included holoprosencephaly, Dandy-Walker malformation, and hypoxic-ischemic encephalopathy changes. Conclusion Complete agenesis of the corpus callosum is significantly associated with other commissural abnormalities, midline cysts, Probst bundle formation, ventricular distortions, and cortical malformations compared to partial agenesis. This study highlights the varied imaging presentations of corpus callosum malformations and their associated anomalies.

[Congenital brain malformations]

CLINICAL ISSUE

Malformations of the central nervous system belong to the most common developmental disorders in humans. The clinical presentation of brain malformations is nonspecific including developmental delay, hypotonia, and/or epilepsy. The great heterogeneity concerning etiology, mechanisms of development and morphology is challenging for diagnosis and classification of brain malformations. Thereby recognizing specific malformations is essential for optimal patient management and prognostic evaluation. The aim of this article is to give an overview of several clinically relevant brain malformations occurring from different disrupted developmental processes in brain formation.

STANDARD RADIOLOGICAL METHODS

Several brain malformations are already diagnosed during routine ultrasound in pregnancy. However pre- and postnatal magnetic resonance imaging remains the gold standard in detecting the partially subtle changes and to classify the malformations.

METHODICAL INNOVATIONS

Advances in pre- and postnatal neuroimaging techniques and increasing investigation of genetic mechanisms underlying brain formation and its abnormalities have led to a better understanding of embryologic development and pathogeneses of brain malformations.

CONCLUSION

Besides patient's history and clinical phenotype, neuroimaging plays a key role in diagnosis. Not always a specific diagnosis can be made, but neuroimaging patterns often enable a focused genetic testing and therefore are revolutionary for etiologic and prognostic assignment. Basic knowledge of brain development facilitates understanding and classifying of structural brain abnormalities.