Bayraktar, O. E. et al. Nat. Neurosci. 23, 500–509 (2020).
The layered organization of the cortex is well established for mammalian brains, but whether astrocytes exhibit spatial heterogeneity has been unclear. To assess spatial diversity, Bayraktar et al. have established a pipeline consisting of multiplexed single-molecule fluorescence in situ hybridization, high-resolution imaging, cell segmentation and quantification. To analyze astrocyte diversity in the mouse cortex, the researchers first identified candidate genes by dissecting the upper and lower cortex, purifying astrocytes and performing transcriptomic analysis. Using their pipeline, the authors then established that astrocytes formed three layers that were not congruent with neuronal layers. Furthermore, the researchers observed differences in layered gene expression in different cortical areas.