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Human brain

motor cortex. Human brain. thalamus. deep cerebellar nuclei. motor cortex. Macaque brain. thalamus. deep cerebellar nuclei. Put coronals of the DCbN. Put pic of DCbN nissl (same subject). thalamus Craig (2004) J. Comp. Neurol. 477:119–148. anterograde analyzes of the

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Human brain

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  1. motor cortex Human brain thalamus deep cerebellar nuclei

  2. motor cortex Macaque brain thalamus deep cerebellar nuclei

  3. Put coronals of the DCbN Put pic of DCbN nissl (same subject)

  4. thalamus Craig (2004) J. Comp. Neurol. 477:119–148 anterograde analyzes of the cerebellothalamic tract projections: posterior Vogt, C. (1909). La myéloarchitecture du thalamus du cercopithèque. Journal of Psychology and Neurology, 12, 285. Mehler, W. R., Vernier, V. G. and Nauta, W. J. H. (1958). Efferent projections from the dentate and interpositus nuclei in primates. Anatomical Records, 130, 430. Mehler, W. R. (1971). Idea of a new anatomy of the thalamus. Journal of Psychiatry Research, 8, 203-217. Kievit, J. (1977).Cerebello-thalamische projecties en de afferente verbindingen naar de frontaalschors in de rhesusaap [translation from Dutch kindly offered by J. Voogd], Erasmus University, Rotterdam. Chan-Palay, V. (1977).Cerebellar dentate nucleus: Organization, cytology and transmitters. Springer-Verlag, Berlin - Heidelberg. Thach, W. T. and Jones, E. G. (1979).The cerebellar dentatothalamic connection: terminal field, lamellae, rods and somatotopy. Brain Research, 169, 168-172. Stanton, G. B. (1980). Topographical Organization of Ascending Cerebellar Projections From the Dentate and Interposed Nuclei in Macaca mulatta: An Anterograde Degeneration Study. Journal of Comparative Neurology, 190, 669-731. Kalil, K. (1981). Projections of the cerebellar and dorsal column nuclei upon the thalamus of the rhesus monkey. Journal of Comparative Neurology, 195, 25-50. Asanuma, C., Thach, W. R. and Jones, E. G. (1983a). Anatomical evidence for segregated focal groupings of efferent cells and their terminal ramifications in the cerebellothalamic pathway of the monkey. Brain Research, 286, 267-297. Asanuma, C., Thach, W. T. and Jones, E. G. (1983b). Distribution of cerebellar terminations and their relation to other afferent terminations in the ventral lateral thalamic region of the monkey. Brain Research, 286, 237-265. Sakai, S. T. and Patton, K. (1993). Distribution of cerebellothalamic and nigrothalamic projections in the dog: a double anterograde tracing study. Journal of Comparative Neurology,330, 183-194. Rouiller, E. M., Liang, F., Babalian, A., Moret, V. and Wiesendanger, M. (1994). Cerebellothalamocortical and pallidothalamocortical projections to the primary and supplementary motor cortical areas: a multiple tracing study in macaque monkeys. Journal of Comparative Neurology, 345, 185-213. Sakai, S. T., Inase, M. and Tanji, J. (1996). Comparison of cerebellothalamic and pallidothalamic projections in the monkey (Macaca fuscata): a double anterograde labeling study. Journal of Comparative Neurology, 368, 215-228. Percheron, G., Francois, C., Talbi, B., Yelnik, J. and Fenelon, G. (1996). The primate motor thalamus. Brain Res Brain Res Rev, 22, 93-181. Sakai, S. T., Inase, M. and Tanji, J. (1999). Pallidal and cerebellar inputs to thalamocortical neurons projecting to the supplementary motor area in Macaca fuscata: a triple-labeling light microscopic study. Anat Embryol (Berl), 199, 9-19. Mason, A., Ilinsky, I. A., Maldonado, S. and Kultas-Ilinsky, K. (2000). Thalamic terminal fields of individual axons from the ventral part of the dentate nucleus of the cerebellum in Macaca mulatta. Journal of Comparative Neurology, 421, 412-428. Stepniewska, I., Sakai, S. T., Qi, H. X. and Kaas, J. H. (2003). Somatosensory input to the ventrolateral thalamic region in the macaque monkey: potential substrate for parkinsonian tremor. Journal of Comparative Neurology, 455, 378-395. Calzavara, R., Zappala, A., Rozzi, S., Matelli, M. and Luppino, G. (2005). Neurochemical characterization of the cerebellar-recipient motor thalamic territory in the macaque monkey. Eur J Neurosci, 21, 1869-1894. • ventrolateral nucleus • posteroventral (VLpv)  M1 (somatomotor) • posterodorsal (VLpd)  M1 (somatomotor) • area X (X)  PMv (visuomotor, audiomotor…) • intralaminar complex • central lateral (CL)  “diffuse”, M1, PMv, … (attention?) • mediodorsal (MD)  FEF (occulomotor) • centromedian (CM)  M1, putamen • parafascicular (Pf)  “limbic” areas, caudate anterior

  5. ventrolateral nucleus • Posteroventral (VLpv)  M1 (somatomotor) • posterodorsal (VLpd)  M1 (somatomotor) • area X (X)  PMv (visuomotor, audiomotor…) • intralaminar complex • central lateral (CL)  “diffuse”, M1, PMv, striatum… (attention?) • mediodorsal (MD)  FEF (occulomotor) • centromedian (CM)  M1, putamen • parafascicular (Pf)  “limbic” areas, caudate

  6. thalamic labeling (continued) WGA-HRP calbindin cerebellar injections

  7. thalamic labeling (continued) WGA-HRP calbindin cerebellar injections

  8. Plan • 1. Absence of fine body representation within the CTT projections to VLpv • 2. Cerebellar projections to the central lateral nucleus of the thalamus: new dual pathway from cerebellum to primary motor cortex • 3. Other works: • Architectonic of the insular cortex • Hodology of the insular cortex • fMRI • Neuroendocrinology: estrogen synthesis in the spinal cord and sexual arousal

  9. Cerebello-thalamo-cortical pathway: key component of the motor system • 1. Cerbellar projections to the ventral lateral nucleus of the thalamus: body representation (“somatotopy”) in the motor system. primary motor cortex thalamus (VL + CL) deep cerebellar nuclei • Largest pathway in the human brain • Fine coordination of movements (ataxia, tremor) • Learning of new movements • Cognitive functions?

  10. Homonculus of the cerebellothalamocortical pathway: “The little man inside the brain” Penfield and Rasmunssen, 1950

  11. Anterograde tracing Asanuma et al. Brain Res. Rev. 5 (1983) 267-297

  12. Transneuronal (viral) retrograde tracing Dum and Strick Ann. NY Acad. Sci. 2002, 978:289-301

  13. Peinfield and Rasmunsen, 1951 Kwan et al. 1978 Shambes et al. 1972 CLASSICAL VIEW: SOMATOTOPY and POINT-TO-POINT PROJECTIONS Transneuronal (viral) retrograde tracing Anterograde retrograde tracing Deep cerebellar nuclei are “somatotopically” organized. They contain fine-grained representation of body parts like in the somatosensory lemniscal system. The cerebellothalamic projections are “point-to-point”; they are neither convergent nor divergent. Dum and Strick 2002 Asanuma et al. 1983

  14. “Motor control researchers argue about many issues, but for the most part they seem to tacitly agree on one point: avoid the thalamus.” (M. Sommer, 2003) “Two characteristics of the thalamus—its apparently simple relay function and its daunting multinuclear structure — have been customarily viewed as good reasons to study something else.” (M. Sommer, 2003) “The thalamus is a mess.” CLASSICAL VIEW: SOMATOTOPY and POINT-TO-POINT PROJECTIONS Transneuronal (viral) retrograde tracing Anterograde retrograde tracing Mononeuronal retrograde tracing ?

  15. “Motor control researchers argue about many issues, but for the most part they seem to tacitly agree on one point: avoid the thalamus.” (M. Sommer, 2003) “Two characteristics of the thalamus—its apparently simple relay function and its daunting multinuclear structure — have been customarily viewed as good reasons to study something else.” (M. Sommer, 2003) “The thalamus is a mess.” CLASSICAL VIEW: SOMATOTOPY and POINT-TO-POINT PROJECTIONS NEW VIEW: NO FINE SOMATOTOPY and INTRICATE PROJECTIONS Mononeuronal retrograde tracing ?

  16. “Motor control researchers argue about many issues, but for the most part they seem to tacitly agree on one point: avoid the thalamus.” (M. Sommer, 2003) “Two characteristics of the thalamus—its apparently simple relay function and its daunting multinuclear structure — have been customarily viewed as good reasons to study something else.” (M. Sommer, 2003) “The thalamus is a mess.” CLASSICAL VIEW: SOMATOTOPY and POINT-TO-POINT PROJECTIONS NEW VIEW: NO FINE SOMATOTOPY and INTRICATE PROJECTIONS Mononeuronal retrograde tracing ?

  17. Massive injections (all thalamus) and very large injections (all ventral lateral nucleus): Highly inhomogeneous + all DCbN project to thalamus but only the anterior parts of DCbN project to VL

  18. Injection sites

  19. Somatotopography, dispersion, and overlap of retrograde labeling Evrard & Craig (2008) J. Comp. Neurol. 508:286–314

  20. Somatotopography, dispersion, and overlap of retrograde labeling Evrard & Craig (2008) J. Comp. Neurol. 508:286–314

  21. Somatotopography, dispersion, and overlap of retrograde labeling Evrard & Craig (2008) J. Comp. Neurol. 508:286–314

  22. Injection sites

  23. Multiple injections in VL: somatotopography + complex intermingling + no double labeled cells

  24. SUMMARY • All DCbN project to the thalamus • Only the anterior portion of the DCbN project to VL • Inhomogeneous distribution (clusters and patches – unlabeled neurons) • Wide dispersion (large vs. small – converging inputs – not “point-to-point”) • Coarse somatotopography (not a fine somatotopy) • Overlap and intermingling (divergence – not “point-to-point”) • Almost no double labeled neurons (intricate but specific projections?)

  25. COMPARISON WITH PREVIOUS STUDIES Anterograde tracing: evidence of divergence Mason et al. 2000 Asanuma et al. 1983

  26. COMPARISON WITH PREVIOUS STUDIES Transneuronal retrograde tracing Dum and Strick, 2003 Lu et al., 2007 Hoover and Strick, 1999 Lu et al., 2007

  27. COMPARISON WITH PREVIOUS STUDIES Retrograde tracing Tracey et al., 1980

  28. COMPARISON WITH PREVIOUS STUDIES Physiology Allen et al., 1978

  29. FUNCTIONAL IMPLICATIONS • Motor synergies (coordinated movement)

  30. FUNCTIONAL IMPLICATIONS • Motor synergies (coordinated movement) • Synaptic plasticity (adaptation and learning – weakening and strengthening of specific connections)

  31. FUNCTIONAL IMPLICATIONS • Motor synergies (coordinated movement) • Synaptic plasticity (adaptation and learning) • Principle of organization of the entire motor system (spinal interneurons)

  32. Plan • 1. Cerbellar projections to the ventral lateral nucleus of the thalamus: body representation (“somatotopy”) in the motor system. • 2. Cerbellar projections to the central lateral nucleus of the thalamus: new dual pathway from cerebellum to primary motor cortex • 3. Other works: • Architectonic of the insular cortex • Hodology of the insular cortex • fMRI • Neuroendocrinology: estrogen synthesis in the spinal cord and sexual arousal

  33. Transneuronal tracing: “Segregated output channels” Dum and Strick, 2003 Cerebellar projections to other thalamic regions: central lateral nucleus (CL) • Topography of projection to CL vs. VL? • Importance of the projection to CL? CL? Asanuma et al. 1983

  34. Labeling from CL

  35. Labeling from CL

  36. Labeling from CL vs. VL: new dual pathway to M1… Retrograde labeling in the dentate Anterograde labeling inM1

  37. Labeling from CL vs. VL: new dual pathway to M1… Retrograde labeling in the dentate Dentate CL VL Anterograde labeling inM1 M1 Functions? Association of “motor synergy” and “attention/bias selection” pathways?

  38. Transneuronal tracing: “Segregated output channels” Dum and Strick, 2003 Retrograde tracing: Topographically organized but not segregated (overlap and intermingling)

  39. “[We] kicked off our shoes and danced in the pool. Without music, you focus more on the sound of your feet, you just engage more of your senses. The splashing of the water kept a certain rhythm that was easy to keep up with.” Cassandra Kagiyama

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