A quantitative study of brainstem projections from lamina I neurons in the cervical and lumbar enlargement of the rat

Polgár, E., Wright, L. L. and Todd, A. J. (2010) A quantitative study of brainstem projections from lamina I neurons in the cervical and lumbar enlargement of the rat. Brain Research, 1308, pp. 58-67. (doi: 10.1016/j.brainres.2009.10.041)

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Publisher's URL: http://dx.doi.org/10.1016/j.brainres.2009.10.041


Lamina I of the rat spinal cord contains neurons that project to various brain areas including thalamus, periaqueductal grey matter (PAG), lateral parabrachial area (LPb), caudal ventrolateral medulla and a region in dorsal medulla that includes the nucleus tractus solitarius and dorsal reticular nucleus. We have shown that spinothalamic lamina I neurons are infrequent in rat lumbar enlargement, where they constitute ∼ 5% of the estimated 400 projection neurons on each side of the L4 segment (Al-Khater and Todd, 2009). They are more numerous in cervical enlargement, but the total number of lamina I projection neurons in this region was not known. Here we have used paired injections of retrograde tracers into the brainstem to estimate the number of lamina I projection cells in the C7 segment. Our results suggest that there are ∼ 215 lamina I projection cells per side, and that spinothalamic cells therefore make up ∼ 42% of this population. The proportion of lamina I projection neurons labelled from PAG is higher in cervical than lumbar enlargement, while the proportion labelled from dorsal medulla is similar in the two regions. We also found that lamina I cells in L4 that project to the dorsal medulla are included in the population retrogradely labelled from LPb, thus confirming the estimate that there are around 400 lamina I projection cells in this segment.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Beresford-Polgar, Dr Erika and Todd, Professor Andrew
Authors: Polgár, E., Wright, L. L., and Todd, A. J.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:Brain Research
ISSN (Online):1872-6240
Published Online:23 October 2009
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Brain Research 1308:58-67
Publisher Policy:Reproduced under a Creative Commons License

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