#80: El tracto corticoespinal: All in

En este episodio, nos sumergimos en la vía motora más determinante del sistema nervioso humano: el tracto corticoespinal. A través de un recorrido detallado por su evolución, desarrollo, anatomía y función, analizamos por qué esta vía representa la gran apuesta evolutiva por la motricidad fina y por qué su lesión tiene consecuencias tan devastadoras. Hablamos de neurofisiología, de plasticidad, de evaluación con TMS y DTI, de terapias intensivas, neuromodulación, farmacología, robótica y de las posibilidades —y límites— reales de su regeneración tras un ictus. Si te interesa entender en profundidad cómo se ejecuta el movimiento voluntario y qué ocurre cuando esa vía falla, este episodio es para ti. Referencias del episodio: 1. Alawieh, A., Tomlinson, S., Adkins, D., Kautz, S., & Feng, W. (2017). Preclinical and Clinical Evidence on Ipsilateral Corticospinal Projections: Implication for Motor Recovery. Translational stroke research, 8(6), 529–540. https://doi.org/10.1007/s12975-017-0551-5 (https://pubmed.ncbi.nlm.nih.gov/28691140/). 2. Cho, M. J., Yeo, S. S., Lee, S. J., & Jang, S. H. (2023). Correlation between spasticity and corticospinal/corticoreticular tract status in stroke patients after early stage. Medicine, 102(17), e33604. https://doi.org/10.1097/MD.0000000000033604 (https://pubmed.ncbi.nlm.nih.gov/37115067/). 3. Dalamagkas, K., Tsintou, M., Rathi, Y., O'Donnell, L. J., Pasternak, O., Gong, X., Zhu, A., Savadjiev, P., Papadimitriou, G. M., Kubicki, M., Yeterian, E. H., & Makris, N. (2020). Individual variations of the human corticospinal tract and its hand-related motor fibers using diffusion MRI tractography. Brain imaging and behavior, 14(3), 696–714. https://doi.org/10.1007/s11682-018-0006-y (https://pubmed.ncbi.nlm.nih.gov/30617788/). 4. Duque-Parra, Jorge Eduardo, Mendoza-Zuluaga, Julián, & Barco-Ríos, John. (2020). El Tracto Cortico Espinal: Perspectiva Histórica. International Journal of Morphology, 38(6), 1614-1617. https://dx.doi.org/10.4067/S0717-95022020000601614 (https://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-95022020000601614). 5. Eyre, J. A., Miller, S., Clowry, G. J., Conway, E. A., & Watts, C. (2000). Functional corticospinal projections are established prenatally in the human foetus permitting involvement in the development of spinal motor centres. Brain : a journal of neurology, 123 ( Pt 1), 51–64. https://doi.org/10.1093/brain/123.1.51 (https://pubmed.ncbi.nlm.nih.gov/10611120/). 6. He, J., Zhang, F., Pan, Y., Feng, Y., Rushmore, J., Torio, E., Rathi, Y., Makris, N., Kikinis, R., Golby, A. J., & O'Donnell, L. J. (2023). Reconstructing the somatotopic organization of the corticospinal tract remains a challenge for modern tractography methods. Human brain mapping, 44(17), 6055–6073. https://doi.org/10.1002/hbm.26497 (https://pubmed.ncbi.nlm.nih.gov/37792280/). 7. Huang, L., Yi, L., Huang, H., Zhan, S., Chen, R., & Yue, Z. (2024). Corticospinal tract: a new hope for the treatment of post-stroke spasticity. Acta neurologica Belgica, 124(1), 25–36. https://doi.org/10.1007/s13760-023-02377-w (https://pubmed.ncbi.nlm.nih.gov/37704780/). 8. Kazim, S. F., Bowers, C. A., Cole, C. D., Varela, S., Karimov, Z., Martinez, E., Ogulnick, J. V., & Schmidt, M. H. (2021). Corticospinal Motor Circuit Plasticity After Spinal Cord Injury: Harnessing Neuroplasticity to Improve Functional Outcomes. Molecular neurobiology, 58(11), 5494–5516. https://doi.org/10.1007/s12035-021-02484-w (https://pubmed.ncbi.nlm.nih.gov/34341881/). 9. Kwon, Y. M., Kwon, H. G., Rose, J., & Son, S. M. (2016). The Change of Intra-cerebral CST Location during Childhood and Adolescence; Diffusion Tensor Tractography Study. Frontiers in human neuroscience, 10, 638. https://doi.org/10.3389/fnhum.2016.00638 (https://pubmed.ncbi.nlm.nih.gov/28066209/). 10. Lemon, R. N., Landau, W., Tutssel, D., & Lawrence, D. G. (2012). Lawrence and Kuypers (1968a, b) revisited: copies of the original filmed material from their classic papers in Brain. Brain : a journal of neurology, 135(Pt 7), 2290–2295. https://doi.org/10.1093/brain/aws037 (https://pubmed.ncbi.nlm.nih.gov/22374938/). 11. Li S. (2017). Spasticity, Motor Recovery, and Neural Plasticity after Stroke. Frontiers in neurology, 8, 120. https://doi.org/10.3389/fneur.2017.00120 (https://pubmed.ncbi.nlm.nih.gov/28421032/). 12. Liu, Z., Chopp, M., Ding, X., Cui, Y., & Li, Y. (2013). Axonal remodeling of the corticospinal tract in the spinal cord contributes to voluntary motor recovery after stroke in adult mice. Stroke, 44(7), 1951–1956. https://doi.org/10.1161/STROKEAHA.113.001162 (https://pubmed.ncbi.nlm.nih.gov/23696550/). 13. Liu, K., Lu, Y., Lee, J. K., Samara, R., Willenberg, R., Sears-Kraxberger, I., Tedeschi, A., Park, K. K., Jin, D., Cai, B., Xu, B., Connolly, L., Steward, O., Zheng, B., & He, Z. (2010). PTEN deletion enhances the regenerative ability of adult corticospinal neurons. Nature neuroscience, 13(9), 1075–1081. https://doi.org/10.1038/nn.2603 (https://pubmed.ncbi.nlm.nih.gov/20694004/). 14. Schieber M. H. (2007). Chapter 2 Comparative anatomy and physiology of the corticospinal system. Handbook of clinical neurology, 82, 15–37. https://doi.org/10.1016/S0072-9752(07)80005-4 (https://pubmed.ncbi.nlm.nih.gov/18808887/). 15. Stinear, C. M., Barber, P. A., Smale, P. R., Coxon, J. P., Fleming, M. K., & Byblow, W. D. (2007). Functional potential in chronic stroke patients depends on corticospinal tract integrity. Brain : a journal of neurology, 130(Pt 1), 170–180. https://doi.org/10.1093/brain/awl333 (https://pubmed.ncbi.nlm.nih.gov/17148468/). 16. Usuda, N., Sugawara, S. K., Fukuyama, H., Nakazawa, K., Amemiya, K., & Nishimura, Y. (2022). Quantitative comparison of corticospinal tracts arising from different cortical areas in humans. Neuroscience research, 183, 30–49. https://doi.org/10.1016/j.neures.2022.06.008 (https://pubmed.ncbi.nlm.nih.gov/35787428/). 17. Ward, N. S., Brander, F., & Kelly, K. (2019). Intensive upper limb neurorehabilitation in chronic stroke: outcomes from the Queen Square programme. Journal of neurology, neurosurgery, and psychiatry, 90(5), 498–506. https://doi.org/10.1136/jnnp-2018-319954 (https://pubmed.ncbi.nlm.nih.gov/30770457/). 18. Welniarz, Q., Dusart, I., & Roze, E. (2017). The corticospinal tract: Evolution, development, and human disorders. Developmental neurobiology, 77(7), 810–829. https://doi.org/10.1002/dneu.22455 (https://pubmed.ncbi.nlm.nih.gov/27706924/).