Advertisement

Reorganization of the corticospinal tract following neonatal unilateral cortical ablation in rats

      This paper is only available as a PDF. To read, Please Download here.
      The corticospinal tract in the rat after neonatal ablation of the unilateral cerebral cortex was studied morphologically and histochemically using the retrograde and antegrade horseradish peroxidase (HRP) tracing methods. The normal corticospinal tract in the lumbar cord was composed of a number of small and some large axons. In the atrophic corticospinal tract related to the ablated cerebral cortex, the small axons were decreased in number two weeks after the operation. However, new myelinated small axons appeared around day 28 and their diameters increased gradually from after day 56 to day 84. The original large axon in the atrophic corticospinal tract was much more increased in size than that in the corticospinal tract of the non-operated-on control. When HRP was injected into the left cervical cord of the adult rat whose right cerebral cortex had been ablated during the neonatal period, a considerable number of HRP-labeled neurons was seen in the healthy left cerebral cortex. When the corticospinal tract was traced antegradely by injecting HRP into the healthy left cerebral cortex, an aberrant corticospinal tract reaching into the ipsilateral dorsal funiculus was observed. These results give a morphological basis for the well known fact that children who have had brain damage during the neonatal period and early infancy have the capacity for recovery of motor function.

      Key words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Brain and Development
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Raisman G
        Neuronal plasticity in septal nuclei of the adult rat.
        Brain Res. 1969; 14: 25-48
        • Mattews DA
        • Cotman C
        • Lynch G
        An electron microscopic study of lesion-induced synaptogenesis in dentate gyrus of the adult rat. II. Reappearance of morphologically normal synaptic contacts.
        Brain Res. 1976; 115: 23-41
        • Nakamura Y
        • Mizuno N
        • Konishi A
        A quantitative electron microscope study of cerebellar axon terminals on the magnocellular red nucleus neurons in the cat.
        Brain Res. 1978; 147: 17-27
        • Cotman CW
        • Nieto-Sampedro M
        • Harris EW
        Synapse replacement in the nervous system of adult vertebrate.
        Physiol Rev. 1981; 61: 684-784
        • Cotman CW
        • Nieto-Sampedro M
        Cell biology of synaptic plasticity.
        Science. 1984; 225: 1287-1294
        • McWilliams JR
        • Lynch G
        Rate of synaptic replacement in dentate gyrus of adult rat.
        J Comp Neurol. 1983; 214: 370-386
        • Hicks SP
        • D’Amato CJ
        Motor sensory and visual behaviour after hemispherectomy in newborn and mature rats.
        Exp Neurol. 1970; 29: 416-438
        • Leong SK
        • Lund RD
        Anomalous bilateral corticofugal pathways in albino rats after neonatal lesion.
        Brain Res. 1973; 62: 218-221
        • Castro A
        Ipsilateral corticospinal projections after large lesions of cerebral hemisphere in neonatal rat.
        Exp Neurol. 1975; 46: 1-8
        • Leonard CT
        • Goldberger ME
        Consequences of damage to the sensorimotor cortex in neonatal and adult cats. II. Maintenance of exuberant projections.
        Dev Brain Res. 1987; 32: 15-30
        • Kimura H
        Morphological study of dopaminergic mesocortical system in rat brain (in Japanese).
        Kyoto Furitsu Ika Daigaku Zasshi (Kyoto). 1978; 87: 417-429
        • Mesulam MM
        Tetramethyl benzidine for horseradish peroxidase neurohistochemistry: A non-carcinogenic blue reaction-product with superior sensitivity for visualizing neural afferents and efferents.
        Histochem Cytochem. 1978; 26: 106-117
        • Kennard MD
        Age and other factors in motor recovery from precentral lesions in monkeys.
        Am J Physiol. 1936; 115: 138-146
        • Guth L
        Axonal regeneration and functional plasticity in the central nervous system.
        Exp Neurol. 1974; 45: 606-654
        • Kerr FWL
        Structural and functional evidence of plasticity in the central nervous system.
        Exp Neurol. 1975; 48 (Part 2): 16-31
        • Goldberger ME
        • Murray M
        Recovery of movement and axonal sprouting may obey some of the same laws.
        in: Cotman CW plasticity. Raven Press, New York1978: 73-96
        • Janowsky JS
        • Finlay BL
        The outcome of perinatal brain damage: The rôle of normal neuron loss and axon retraction.
        Dev Med Child Neurol. 1986; 28: 375-389
        • Kartje-Tillotson G
        • Naefsey EJ
        • Castro AJ
        Electrophysiological analysis of motor cortical plasticity after cortical lesions in newborn rats.
        Brain Res. 1985; 332: 103-111
        • Bregman BS
        • Goldberger ME
        • Infant lesion effect: III
        anatomical correlates of sparing and recovery of function after spinal cord damage in newborn and adult cats.
        Dev Brain Res. 1983; 9: 137-154
        • Hicks SP
        • D’Amato CJ
        Motor-sensory cortex-corticospinal system and developing locomotion and placing in rats.
        Am J Anat. 1975; 143: 1-42
        • Whishaw IQ
        • Kolb B
        Sparing of skilled forelimb reaching and corticospinal projections after neonatal motor cortex removal or hemidecortication in the rat: support for the Kennard doctrine.
        Brain Res. 1988; 451: 97-114
        • Brown LTJ
        Projections and termination of the corticospinal tract in rodents.
        Exp Brain Res. 1971; 13: 432-450
        • Wise SP
        • Donoghue JP
        Motor cortex of rodents.
        in: Jones EJ Peter A Cerebral cortex. Vol 5. Sensory-motor areas and aspects of cortical connectivity. Pleum Press, New York1986: 243-265
        • Berry M
        • Rogers AW
        The migration of neuroblasts in the developing cerebral cortex.
        J Anat. 1965; 99: 691-709
        • DeMyer W
        Ontogenesis of the rat corticospinal tract.
        Arch Neurol. 1963; 16: 203-211
        • Donatelle JM
        Growth of the corticospinal tract and development of placing reactions in postnatal rat.
        J Comp Neurol. 1977; 175: 207-232
        • Stanfield BB
        • O’Leary DDM
        • Fricks C
        Selective collateral elimination in early postnatal development restricts cortical distribution of rat pyramidal tract neurons.
        Nature. 1982; 296: 371-373
        • Wiesel TN
        • Hubel DH
        Comparison of the effects of unilateral bilateral eye closure on cortical microscopical study.
        J Anat. 1965; 126: 193-201
        • Guillery RW
        Binocular competition in the control of geniculate cell growth.
        J Comp Neurol. 1972; 144: 117-130