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Evolution of the Brain, Cognition, and Emotion in Vertebrates pp 81–98Cite as

Developmental Sequences Predict Increased Connectivity in Brain Evolution: A Comparative Analysis of Developmental Timing, Gene Expression, Neuron Numbers, and Diffusion MR Tractography

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Abstract

A conserved sequence in cell-type specification across mammals suggests that evolutionary changes in developmental timing may give rise to predictable changes in connectivity patterns across species. We here review the regularities in the timing of developmental events across species. We then use them to predict evolutionary changes in the number of cell types in order to identify evolutionary changes in the internal circuitry of the cerebellum as well as the gray and white matter of the isocortex across mammals. We survey what is known about the sequence and timing of cell-type specification in different brain regions and in various mammalian species. We find that lengthened developmental schedules predict a disproportionate increase in the number of locally projecting granule cells within the cerebellum and in the number of isocortical neurons projecting within or across cortical areas. Our main conclusion is that, as brains get bigger, neurons increasingly connect within their own major brain region.

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Acknowledgments

This work was supported by the James S. McDonnell Foundation Grant 22002078 (C. C. S.), the Eunice Shriver Kennedy NICHD R01HD078561 and R21HD069001 (E. T.), as well as a DAAD grant (C. J. C). Images of Nissl-stained sections of primary visual cortex of the macaque and rat as well as the cerebellum of the macaque shown in Figs. 4.4 and 4.5 were obtained by taking screenshots from brainmaps.org. We also used gene expression data from the BrainSpan: Atlas of the Developing Human Brain, funded by ARRA Awards 1RC2MH089921-01, 1RC2MH090047-01, and 1RC2MH089929-01. These data are available from http://developinghumanbrain.org

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Authors and Affiliations

  1. Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA

    Christine J. Charvet & Chet C. Sherwood

  2. Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA

    Christine J. Charvet & Emi Takahashi

  3. Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA

    Christine J. Charvet & Emi Takahashi

  4. Department of Molecular Biology and Genetics, Cornell University, 345 Biotechnology Building, Ithaca, NY, 14853, USA

    Christine J. Charvet

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  1. Christine J. Charvet
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Correspondence to Christine J. Charvet .

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Editors and Affiliations

  1. Keio University, Minato-ku, Tokyo, Japan

    Shigeru Watanabe

  2. Department of Neuropsychiatry, Netherlands Institute for Neuroscience, Amsterdam Zuidoost, Noord-Holland, The Netherlands

    Michel A Hofman

  3. Psychology, University of South Florida, Tampa, Florida, USA

    Toru Shimizu

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Charvet, C.J., Sherwood, C.C., Takahashi, E. (2017). Developmental Sequences Predict Increased Connectivity in Brain Evolution: A Comparative Analysis of Developmental Timing, Gene Expression, Neuron Numbers, and Diffusion MR Tractography. In: Watanabe, S., Hofman, M., Shimizu, T. (eds) Evolution of the Brain, Cognition, and Emotion in Vertebrates. Brain Science. Springer, Tokyo. https://doi.org/10.1007/978-4-431-56559-8_4

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