The neocortex is disproportionately expanded in human compared with mouse1,2, both in its total volume relative to subcortical structures and in the proportion occupied by supragranular layers composed of neurons that selectively make connections within the neocortex and with other telencephalic structures. Single-cell transcriptomic analyses of human and mouse neocortex show an increased diversity of glutamatergic neuron types in supragranular layers in human neocortex and pronounced gradients as a function of cortical depth3. Here, to probe the functional and anatomical correlates of this transcriptomic diversity, we developed a robust platform combining patch clamp recording, biocytin staining and single-cell RNA-sequencing (Patch-seq) to examine neurosurgically resected human tissues. We demonstrate a strong correspondence between morphological, physiological and transcriptomic phenotypes of five human glutamatergic supragranular neuron types. These were enriched in but not restricted to layers, with one type varying continuously in all phenotypes across layers 2 and 3. The deep portion of layer 3 contained highly distinctive cell types, two of which express a neurofilament protein that labels long-range projection neurons in primates that are selectively depleted in Alzheimer’s disease4,5. Together, these results demonstrate the explanatory power of transcriptomic cell-type classification, provide a structural underpinning for increased complexity of cortical function in humans, and implicate discrete transcriptomic neuron types as selectively vulnerable in disease.
Bibliographical noteFunding Information:
Hungarian Academy of Sciences, the National Research, Development and Innovation Office of Hungary GINOP-2.3.2-15-2016-00018, the Ministry of Human Capacities of Hungary 20391-3/2018/FEKUSTRAT to G.T. Neuropathology support was provided in part by the Nancy and Buster Alvord Endowment to C.D.K. Work was supported by the European Union’s Horizon 2020 Framework Programme for Research and Innovation under the specific grant agreement no. 945539 (Human Brain Project SGA3), ERANET programme iPS&BRAIN, and NWO Gravitation program BRAINSCAPES: A Roadmap from Neurogenetics to Neurobiology (NWO: 024.004.012). This work was funded by the Allen Institute for Brain Science. We dedicate this paper to the vision, encouragement, and long-term support of our founder, Paul G. Allen.
Acknowledgements We thank A. Wanner for providing reconstruction services through A. Szeto and R. Szeto, and Z. Popovic for facilitating the reconstruction work contributed by Mozak.science. We also thank the Mozak citizen scientists for their valuable contribution. The research was partially supported by several grant awards from institutes under the National Institutes of Health (NIH), including award U01MH114812 from National Institute of Mental Health, R01EY023173 from The National Eye Institute, U01MH105982 from the National Institute of Mental Health and Eunice Kennedy Shriver National Institute of Child Health & Human Development, and R011EY023173 from The National Institute of Allergy and Infectious Disease. The content is solely the responsibility of the authors and does not necessarily represent the official views of NIH and its subsidiary institutes. Work was supported by the
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