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Diversity and complexity in the pyramidal tract projectome

Nature Reviews Neuroscience volume 15, page 63 (2014)Cite this article

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In their response to my Review (Corticostriatal connectivity and its role in disease. Nature Rev. Neurosci. 14, 278–291 (2013))1, Smith et al. (Corticostriatal and mesocortical dopamine systems: do species differences matter? Nature Rev. Neurosci.http://dx.doi.org/10.1038/nrn3469-c1 (2013))2 highlight fascinating topics and present intriguing new ideas and schematics, which I hope will help to stimulate more research and discussion in these important areas. In this limited space, I focus on the pyramidal tract (PT)-related issues. For primate-related intratelencephalic (IT) versus PT issues, readers are referred to Pasquereau and Turner's pivotal study3, and terminological clarifications may be sought in my Review and references therein1.

The PT system follows a basic mammalian plan, with many evolutionary specializations4,5,6,7,8,9. Smith et al.2 propose a distinction in which the supraspinal branching of single PT axons is extensive in rats but mostly absent in primates. Undoubtedly, PT branching is somehow differentiated across mammals, and the proposed organization may be correct. As touched on below, I wonder whether aspects of this proposal may be considered tentative, but certainly the new formulation offers well-defined starting points for further investigation.

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Acknowledgements

G.M.G.S. has received funding from US National Institutes of Health-National Institute of Neurological Disorders and Stroke grant NS061963 and the Whitehall Foundation.

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  1. Gordon M. G. Shepherd is at the Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.,

    Gordon M. G. Shepherd

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Correspondence to Gordon M. G. Shepherd.

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Shepherd, G. Diversity and complexity in the pyramidal tract projectome. Nat Rev Neurosci 15, 63 (2014). https://doi.org/10.1038/nrn3469-c2

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