Comprehensive cell atlas of the first-trimester developing human brain.

Area of Science:

• Neuroscience
• Developmental Biology
• Genomics

Background:

• The adult human brain exhibits remarkable cellular diversity, with over a thousand neuronal and glial cell types.
• This complexity arises during early embryonic development, a process not fully understood.
• Understanding early brain development is crucial for addressing neurodevelopmental disorders.

Purpose of the Study:

• To precisely map the sequence of cellular events during early human brain development.
• To identify distinct cell states and their developmental trajectories.
• To understand the spatial organization of developing cell types in the human brain.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) to analyze individual cell gene expression.
• Spatial transcriptomics to map cell types to anatomical locations.
• Analysis of human brain tissue from 5 to 14 postconceptional weeks (pcw).

Main Results:

• Identification of 12 major cell classes comprising approximately 600 distinct cell states.
• Mapping of these cell states to precise spatial anatomical domains at 5 pcw.
• Detailed description of differentiation trajectories for the human forebrain and midbrain.
• Discovery of region-specific glioblasts maturing into distinct pre-astrocytes and pre-oligodendrocyte precursor cells.

Conclusions:

• The study reveals the establishment of diverse neuronal and glial cell types during the first trimester of human brain development.
• Provides a comprehensive atlas of early human brain cellular organization and differentiation.
• Offers insights into the origins of cellular diversity in the human brain.