The enormous complexity of the human brain is a function of its precise circuitry, its structural and cellular diversity, and, ultimately, the regulation of its underlying transcriptome. In rodents, brain- and transcriptome-wide, cellular-resolution maps of transcript distributions are widely useful resources to complement genomic sequence data1, 2, 3. However, owing to the challenges of a 1,000-fold increase in size from mouse to human, limitations in post-mortem tissue availability and quality, and the destructive nature of molecular assays, there has been no human counterpart so far. Several important recent studies have begun to analyse transcriptional dynamics during human brain development4, 5, although only in a small number of relatively coarse brain regions. Characterizing the complete transcriptional architecture of the human brain will provide important information for understanding the impact of genetic disorders on different brain regions and functional circuits. Furthermore, conservation and divergence in brain function between humans and other species provide essential information for the understanding of drug action, which is often poorly conserved across species6.
