Cellular Diversity Underpins Cortical Organization and Disease Vulnerability in the Human Brain.

Scientists studied how different types of brain cells are arranged in different areas of the brain. They found three main patterns of brain organization and discovered that certain cell types are linked to specific brain disorders including autism, depression, and schizophrenia. This research helps us understand how the brain's cellular makeup might contribute to these conditions.

This study integrated single-cell RNA sequencing data with brain atlas microarray data to map how different cell types are distributed across human cortical regions. Researchers identified three major cortical classes (sensory/motor, anterior association, and posterior association) characterized by distinct cell-type enrichments. The distribution of dominant neuronal subtypes correlated with variations in brain layer thickness. By analyzing cortical shrinkage patterns in autism spectrum disorder, major depressive disorder, and schizophrenia, the study used predictive modeling to identify how specific cell types may contribute to each psychiatric disorder, providing new insights into the cellular basis of these conditions.

Findings suggest cellular organization patterns may underlie vulnerability to psychiatric disorders including autism. This could inform development of more targeted interventions and improve understanding of why certain brain regions are affected in specific conditions.

Sample size not reported. Study relies on integration of different data types which may introduce methodological variability. Predictive modeling results require validation. Causal relationships between cell-type distributions and disorders not established.

The cellular organization of the human brain fundamentally shapes its structure, function, and vulnerability to psychiatric disorders. However, the specific cellular contributions to laminar architecture and disease susceptibility remain elusive. Here, we estimated the distribution of molecularly defined cell types across cortical regions by integrating human single-nucleus RNA sequencing data with the Allen Human Brain Atlas microarray data. The cellular distribution profiles delineated three major cortical classes: sensory/motor, anterior association, and posterior association, each characterized by distinct cell-type enrichments.

The dominant neuronal subtypes within each class exhibited specific laminar preferences that matched the variations in laminar thickness, as quantified using the BigBrain 3D histological atlas. Specifically, granular layer excitatory and parvalbumin-positive interneurons dominated sensory regions, while supragranular and infragranular neuronal subtypes enriched association cortices. Finally, by linking cell-type distributions to cortical shrinkage patterns in autism spectrum disorder, major depressive disorder, and schizophrenia, we identified cell-type-specific contributions to each disorder through predictive modeling. These findings illuminate the crucial role of cellular organization in shaping cortical structure and function, providing new insights into the cellular underpinnings of psychiatric disorders.