GABAergic interneuron migration and the evolution of the neocortex

Authors

  • Daisuke H. Tanaka,

    Corresponding author
    • Department of Anatomy, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
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    • Present address: Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), Brussels, B-1070, Belgium.
  • Kazunori Nakajima

    Corresponding author
    • Department of Anatomy, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
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Authors to whom all correspondence should be addressed.

Email: emaniatahon@gmail.com; kazunori@z6.keio.jp

Abstract

A neocortex is present in all mammals but is not present in other classes of vertebrates, and the neocortex is extremely elaborate in humans. Changes in excitatory projection neurons and their progenitors within the developing dorsal pallium in the most recent common ancestor of mammals are thought to have been involved in the evolution of the neocortex. Our recent findings suggest that changes in the migratory ability of inhibitory interneurons derived from outside the neocortex may also have been involved in the evolution of the neocortex. In this article we review the literature on the migratory profile of inhibitory interneurons in several different species and the literature on comparisons between the intrinsic migratory ability of interneurons derived from different species. Finally, we propose a hypothesis about the mammalian-specific evolution of the migratory ability of interneurons and its potential contribution to the establishment of a functional neocortex.

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