Summary
The projection from the cerebral cortex to the nucleus reticularis tegmenti pontis (NRT) has been studied in the rhesus monkey with silver impregnation methods. The majority of cortical afferents to NRT arise in the precentral motor cortex (area 4), while more modest contributions come from the premotor region (area 6), the somatosensory cortex (areas 3, 1, and 2) and area 5. Very few, if any, degenerating fibres were observed in the NRT after lesions of other parts of the cortex. The cortical afferents terminate throughout NRT except in its dorsomedial part. There is a topographical arrangement so that fibres from area 6 terminate most medially in the NRT, fibres from area 5 most laterally (in the processus tegmentosus lateralis), while fibres from the motor cortex end in between and cover the largest terminal field. In addition, the projection from the motor cortex is somatotopically organized with the leg represented ventrally and the arm dorsally in the NRT. There is, however, ample overlap between the terminal regions of fibres from the various cortical areas. The results are discussed in relation to the termination of other afferent contingents to the NRT, and it is concluded that even if there is a high degree of convergence, various parts of the NRT appear not to receive identical sets of afferent inputs.
Similar content being viewed by others
References
Allen, G.I., Tsukahara, N.: Cerebrocerebellar communication systems. Physiol. Rev. 54, 957–1006 (1974).
Brodal, A.: Cerebrocerbellar pathways. Anatomical data and some functional implications. Acta Neurol. Scand. [Suppl.] 51, 153–196 (1972).
Brodal, A., Brodal, P.: The organization of the nucleus reticularis tegmenti pontis in the cat in the light of experimental anatomical studies of its cerebral cortical afferents. Exp. Brain Res. 13, 90–110 (1971).
Brodal, A., Szikla, G.: The termination of the brachium conjunctivum descendons in the nucleus reticularis tegmenti pontis. An experimental anatomical study in the cat. Brain Res. 39, 337–351 (1972).
Brodal, A., Lacerda, A.M., Destombes, J., Angaut, P.: The pattern in the projection of the intracerebellar nuclei onto the nucleus reticularis tegmenti pontis in the cat. An experimental anatomical study. Exp. Brain Res. 16, 140–160 (1972).
Brodal, P.: The corticopontine projection in the rhesus monkey. Origin and principles of organization. Brain 101, 251–283 (1978).
Brodal, P.: The pontocerebellar projection in the rhesus monkey: An experimental study with retrograde axonal transport of horseradish peroxidase. Neuroscience 4, 193–208 (1979a).
Brodal, P.: The projection from the nucleus reticularis tegmenti pontis to the cerebellum in the rhesus monkey. Exp. Brain Res. 38, 29–36 (1980).
Brodal, P., Maršala, J., Brodal, A.: The cerebral cortical projection to the lateral reticular nucleus in the cat, with special reference to the sensorimotor cortical areas. Brain Res. 6, 252–274 (1967).
Brodmann, K.: Vergleichende Lokalisationslehre der Groβhirnrinde. Leipzig: Barth 1909.
Carpenter, M.B.: Lesions of the fastigial nuclei in the rhesus monkey. Am. J. Anat. 104, 1–34 (1959).
Carpenter, M.B., Nova, H.R.: Descending division of the brachium conjunctivum in the cat: A cerebello-reticular system. J. Comp. Neurol. 114, 295–305 (1960).
Carrea, P.M.E., Mettler, F.A.: The anatomy of the primate brachium conjunctivum and associated structures. J. Comp. Neurol. 101, 565–689 (1954).
Coulter, J.D., Ewing, L., Carter, C.: Origin of primary sensorimotor cortical projections to lumbar spinal cord of cat and monkey. Brain Res. 103, 366–372 (1976).
Dhanarajan, P., Rüegg, D.G., Wiesendanger, M.: An anatomical investigation of the corticopontine projection in the primate (Saimiri sciureus). The projection from motor and somatosensory areas. Neuroscience 2, 913–922 (1977).
Edwards, S.B.: Autoradiographic studies of the projections of the midbrain reticular formation: Descending projections of nucleus cuneiformis. J. Comp. Neurol. 161, 341–358 (1975).
Fink, R.P., Heimer, L.: Two methods for selective silver impregnation of degenerating axons and their synaptic endings in the central nervous system. Brain Res. 4, 369–374 (1967).
Karting, J.K.: Descending pathways from the superior colliculus: An autoradiographic analysis in the rhesus monkey (Macaca mulatta). J. Comp. Neurol. 173, 583–612 (1977).
Hoddevik, G.H.: The projection from the nucleus reticularis tegmenti pontis onto the cerebellum in the cat. Anat. Embryol. 153, 227–242 (1978).
Jones, E.G., Powell T.P.S.: Connexions of the somatic sensory cortex of the rhesus monkey. II. Contralateral cortical connexions. Brain 92, 717–730 (1969).
Jones, E.G., Powell, T.P.S.: An anatomical study of converging sensory pathways within the cerebral cortex and the monkey. Brain 93, 793–820 (1970).
Jones, E.G., Wise, S.P.: Size, laminar and columnar distibution of efferent cells in the sensory-motor cortex of monkeys. J. Comp. Neurol. 175, 391–438 (1977).
Kawamura, K., Brodal, A., Hoddevik, G.: The projection of the superior colliculs onto the reticular formation of the brain stem. An experimental anatomical study in the cat. Exp. Brain Res. 19, 1–19 (1974).
Kemp, J., Powell, T.P.S.: The cortico-striate projection in the monkey. Brain 93, 525–546 (1970).
Kitai, S.T., Kocsis, J.D., Kiyohara, T.: Electrophysiological properties of nucleus reticularis tegmenti pontis cells: antidromic and synaptic activation. Exp. Brain Res. 24, 295–309 (1976).
Kuypers, H.G.J.M.: Some projections from the pericentral cortex to the pons and lower brain stem in monkey and chimpanzee. J. Comp. Neurol. 110, 221–252 (1958).
Kuypers, H.G.J.M.: Central cortical projections to motor and somatosensory cell groups. An experimental study in the rhesus monkey. Brain 83, 161–184 (1960).
Kuypers, H.G.J.M., Lawrence, D.G.: Cortical projections to the red nucleus and the brain stem in the rhesus monkey. Brain Res. 4, 151–188 (1967).
Kunzle, H.: An autoradiographic analysis of the efferent connections from premotor and adjacent prefrontal regions (areas 6 and 9) in Macaca fascicularis. Brain Behav. Evol. 15, 185–234 (1978).
Künzle, H., Akert, K.: Efferent connections of cortical area 8 (Frontal eye field) in Macaca fascicularis. A reinvestigation using the autoradiographic technique. J. Comp. Neurol. 173, 147–163 (1977).
Ladpli, R., Brodal, A.: Experimental studies of commissural and reticular projections from the vestibular nuclei in the cat. Brain Res. 8, 65–96 (1968).
McMasters, R.E., Weiss, A.H., Carpenter, M.B.: Vestibular projections to the nuclei of the extraocular muscles. Degeneration resulting from discrete partial lesions of the vestibular nuclei in the monkey. Am J. Anat. 118, 163–194 (1966).
Miller, R.A., Strominger, N.L.: An experimental study of the efferent connections of the superior cerebellar peduncle in the rhesus monkey. Brain Res. 133, 237–250 (1977).
Nauta, W.J.H., Gygax, P.A.: Silver impregnation of degenerating axons in the central nervous system: a modified technic. Stain Technol. 29, 91–93 (1954).
Nyby, O., Jansen, J.: An experimental investigation of the corticopontine projection in Macaca mulatta. Norske Vid. Akad. Avh. I, Mat.-Nat. 3, 1–47 (1951).
Olszewski, J., Baxter, D.: Cytoarchitecture of the human brain stem. New York, Basel: Karger 1954.
Pearson, R.C.A., Powell, T.P.S.: The cortico-cortical connections to area 5 of the parietal lobe from the primary somatic sensorycortex of the monkey. Proc. R. Soc. Lond. [Biol.] 200, 103–108 (1978).
Sasaki, K., Oka, H., Kawaguchi, S., Jinnai, K., Yasuda, T.: Mossy and climbing fibre responses produced in the cerebellar cortex by stimulation of the cerebral cortex in monkeys. Exp. Brain Res. 29, 419–428 (1977).
Sousa-Pinto, A.: The cortical projection onto the paramedian reticular and perihypoglossal nuclei (nucleus praepositus hypoglossi, nucleus intercalatus, and nucleus of Roller) of the medulla oblongata of the cat. An experimental anatomical study. Brain Res. 18, 77–91 (1970).
Sousa-Pinto, A., Brodal, A.: Demonstration of a somatotopical pattern in the cortico-olivary projection in the cat. An experimental-anatomical study. Exp. Brain Res. 8, 364–386 (1969).
Tarlov, E.: The rostral projections of the primate vestibular nuclei: An experimental study in Macaque, Baboon and Chimpanzee. J. Comp. Neurol. 135, 27–56 (1969).
Walberg, F., Pompeiano, O., Westrum, L.E., Hauglie-Hansen, E.: Fastigioreticular fibers in the cat. An experimental study with siver methods. J. Comp. Neurol. 119, 187–199 (1962).
Wütanen, J.T.: Selective silver impregnation of degenerating axons and axon terminals in the central nervous system of the monkey. Brain Res. 14, 546–548 (1969).
Woolsey, C.N.: Organization of somatic sensory and motor areas of the cerebral cortex. In: Biological and biochemical bases of behaviour. Harlow, Woolsey (eds.), pp. 63–81. Madison: Madison University of Wisconsin Press, 1958.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Brodal, P. The cortical projection to the nucleus reticularis tegmenti pontis in the rhesus monkey. Exp Brain Res 38, 19–27 (1980). https://doi.org/10.1007/BF00237926
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00237926