Summary
The postnatal development of neuronal perikarya in layers II–VI of the visual cortex of perfusion-fixed albino rats, 12 h to 180 days old, has been studied by electron microscopy. Particular attention was paid to cells in photographic montages of 75μm wide strips extending through the full depth of the occipital cortex, cut from 100 μm vibratome sections of the brain.
At birth, and during the first few postnatal days, most of the neurons present in the cortex are small, tightly packed ‘indifferent’ cells with scanty cytoplasm containing mitochondria and chiefly free ribosomes; a few presumptive pyramidal cells with a developing apical dendrite and more voluminous cytoplasm can be recognized in deep cortex. Non-pyramidal cells can be identified on postnatal day 6, when although scarce and with immature cytoplasmic features, they already display a more electron opaque chromatin pattern than developing pyramidal cells and receive axo-somatic contacts of Gray's type I.
During the second postnatal week there are conspicuous increases in the maturity of the cells, which acquire a rich complement of cytoplasmic organelles: in general cells situated in the deep cortical plate are larger and better differentiated than those in the superficial plate, and non-pyramidal cells are less well differentiated than the associated pyramidal cells. By the end of the second week, differences in cytoplasmic maturity between superficial and deep, and between pyramidal and non-pyramidal cells are less evident.
Maturation proceeds during the third postnatal week; both types of cells acquire an adult complement of axo-somatic synapses and their mature nuclear and cytoplasmic features, and by day 24 are indistinguishable from their adult counterparts. In keeping with previous Golgi studies of this same cortex, the non-pyramidal cells did not acquire mature ultrastructural features significantly later than the pyramidal cells. A possible correlate of particularly active synaptogenesis and plasticity in the population of nonpyramidal, cells during the third postnatal week (immediately after eyeopening), was that at this time these cells contained very prominent accumulations of granular reticulum, ribosomes and Golgi apparatus, and appeared hypertrophic.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Altman, J.: Postnatal growth and differentiation of the mammalian brain, with implications for a morphological theory of memory. In: The Neurosciences. A Study Program. (G.C. Quarton, T. Melnechuk, and F.O. Schmitt (eds) pp. 723–743. New York: Rockefeller University Press, 1967
Åström, K-E.: On the early development of the isocortex in the rat. In: Studies on the development of behavior and the nervous system, Vol. 2, Aspects of neurogenesis (G. Gottlieb, ed.) pp. 7–76. New York: Academic Press 1974
Bradford, R., Parnavelas, J.G., Lieberman, A.R.: Neurons in layer I of the developing occipital cortex of the rat. J. Comp. Neurol. 176, 121–132 (1977)
Butler, A.B., Caley, O.W.: An ultrastructural and radioautographic study of the migrating neuroblast in hamster neocortex. Brain Rex. 44, 83–97 (1972)
Cajal, S.R.y: Histologie du Système Nerveux de l'Homme et des Vertébrés, Vol. II (translated by S. Azoulay). Paris: Maloine 1911
Caley, D.W., Maxwell, D.S.: An electron microscopic study of neurons during postnatal development of the rat cerebral cortex. J. Comp. Neurol. 133, 17–44 (1968)
Colonnier, M.: synaptic patterns on different cell types in the different laminae of the cat visual cortex. An electron microscopic study. Brain Res. 9, 268–287 (1968)
Garey, L.J.: A light and electron microscopic study of the visual cortex of the cat and monkey. Proc. R. Soc. Lond. B 179, 21–40 (1971)
Jacobson, M.: A plentitude of neurons. In: Studies on the development and behaviour of the nervous system. Vol. 2, Aspects of neurogenesis (G. Gottlieb, ed.) pp. 151–166. New York: Academic Press, 1974
Jacobson, M.: Developmental Neurobiology (2nd edition). New York: Plenum Press 1978
König, N., Valat, J., Fulcrand, J., Marty, R.: The time of origin of Cajal-Retzius cells in the rat temporal cortex. An autoradiographic study. Neurosci. Lett. 4, 21–26 (1977)
Lund, J.S., Boothe, R.G., Lund, R.D.: Development of neurons in the visual cortex (area 17) of the monkey (Macaca nemestrina): A Golgi study from fetal day 127 to postnatal maturity. J. Comp. Neurol. 176, 149–188 (1977)
Lund, R.D., Mustari, M.J.: Development of the geniculocortical pathway in rats. J. Comp. Neurol. 173, 289–306 (1977)
Morest, D.K.: The growth of dendrites in the mammalian brain. Z. Anat. Entwickl-Gesch. 128, 290–317 (1969)
Noback, C.R., Purpura, D.P.: Postnatal ontogenesis of neurons in cat neocortex. J. Comp. Neurol. 117, 291–307 (1961)
Parnavelas, J.G., Sullivan, K., Lieberman, A.R., Webster, K.E.: Neurons and their synaptic organization in the visual cortex of the rat. Electron microscopy of Golgi preparations. Cell Tissue, Res. 183, 499–517 (1977)
Parnavelas, J.G., Bradford, R., Mounty, E.J., Lieberman, A.R.: The development of non-pyramidal neurons in the visual cortex of the rat. Anat. Embryol. 155, 1–14 (1978)
Parnavelas, J.G., Luder, R., Pollard, S.G., Sullivan, K., and Lieberman, A.R.: A qualitative and quantitative ultrastructural study of glial cells in the developing visual cortex of the rat. (in preparation)
Peters, A.: The fixation of central nervous tissue and the analysis of electron micrographs of the neuropil, with special reference to the cerebral cortex. In: Contemporary research methods in neuroanatomy (Nauta, W.J.H. and Ebbesson, S.O., eds). pp. 57–76. New York, Heidelberg, Berlin: Springer 1970
Peters, A.: Stellate cells of the rat parietal cortex. J. Comp. Neurol., 141, 345–374 (1971)
Peters, A., Fairén, A.: Smooth and sparsely-spined stellate cells in the visual cortex of the rat: A study using a combined Golgi-electron microscope technique. J. Comp. Neurol. 181, 129–172 (1978)
Peters, A., Kaiserman-Abramof, I.R.: The small pyramidal neuron in the rat cerebral cortex. The perikaryon, dendrites, and spines. Am. J. Anat. 127, 321–356 (1970)
Poliakov, G.I.: Some results of research into the development of the neuronal structure of the cortical ends of the analysers in man. I. Comp. Neurol. 117, 197–212 (1961)
Raedler, A., Sievers, J.: The development of the visual system of the albino rat. Adv. Anat. Embryol. Cell Biol. 50/3, 1–88 (1975)
Raedler, A., Sievers, J.: Light and electron microscopical studies on specific cells of the marginal zone in the developing rat cerebral cortex. Anat. Embryol. 147, 173–181 (1976)
Rakic, P.: Neurons in rhesus monkey visual cortex. Systematic relation between time of origin and eventual disposition. Science 183, 425–427 (1974)
Rakic, P.: Effects of local cellular environments on the differentiation of LCN's. In: Local Circuit Neurons. Neurosci. Res. Program Bull. 13/3, 400–407 (1975)
Rickmànn, M., Chronwall, B.M., Wolff, J.R.: On the development of non-pyramidal neurons and axons outside the cortical plate: the early marginal zone as a pallial anlage. Anat. Embryol. 151, 285–307 (1977)
Sloper, J.J.: An electron microscopic study of the neurons of the primate motor and somatic sensory cortices. J. Neurocytol. 2, 351–359 (1973)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Parnavelas, J.G., Lieberman, A.R. An ultrastructural study of the maturation of neuronal somata in the visual cortex of the rat. Anat Embryol 157, 311–328 (1979). https://doi.org/10.1007/BF00304996
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00304996