Fig. 3: Developmental trajectories of cell-type specific gene expression.

Data shown for samples aged 0-30 years from: (a) BrainCloud (Z-score), and (b) PsychENCODE (expressed in log₂-reads-per-kilobase of transcript per million (log₂RPKM)) datasets, demeaned to account for overall higher expression in some cell-types. Age effects were modelled in all postnatal samples to maximise sample size. Grey shaded areas highlight the age range of the microstructural imaging cohort (8–19 years) for visual comparison of developmental profiles. c SEA results⁸⁹ showing significant enrichment of age-related genes through adolescence and adulthood, where hexagon size scales with enrichment (overlap) of age-related genes in genes expressed by each cell type determined using the Fisher’s exact test⁹¹, and darker rings indicate significant associations at p_FDR < .001 with inner rings indicating high cell specificity. False discovery rate (FDC) was controlled using Benjamini-Hochberg multiple testing correction for the number of cell types and regions assayed⁹². Age-related genes overlapping postnatal developmental stages are shown as (d) total number of genes, and (e) proportion of genes, indicating an increase in neuronal, glial and oligodendrocyte-specific genes. f Trajectories of glial genes overlapping the SEA and our age-genes. g Regional shifts in the glial cell-type expression ratio (log₂RPKM) across development, with the astrocyte-to-oligodendrocyte expression ratio crossing earliest at age 20 years in primary motor and visual cortices. h Timing of this cross-over, with darker values indicating regions with an earlier crossing point. Note that white coloured regions are not represented in the data set. Curves in (a, b, g) represented as mean trajectory with 95% confidence interval bounds. Abbreviations: A1C Primary auditory cortex, DLPFC Dorsolateral pre-frontal cortex, IPC Inferior parietal cortex, ITC Inferior temporal cortex, M1 Primary motor cortex, MFC Medial frontal cortex, OFC Orbito-frontal cortex, OPC oligodendrocyte precursor cell, RPKM rates per kilobase of transcript per million mapped, S1 Primary somatosensory cortex, STC Superior temporal cortex, V1 Primary visual cortex, VLPFC Ventrolateral pre-frontal cortex. Colour coding in (a) corresponds to cell-types in (b, d–f). Source data are provided as a Source Data file.