Effects of electrical stimulation of somatosensory and motor areas of the cerebral cortex on neurones of the pontine nuclei in squirrel monkeys

Rüegg, D. G.; Séguin, J. J.; Wiesendanger, M.

doi:10.1016/0306-4522(77)90115-4

Cited by 35 publications

(13 citation statements)

References 8 publications

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“…In cat, electrophysiological findings by Allen et al (1969Allen et al ( , 1975 indicate that 46% of pontine neurons are activated by collaterals of pyramidal tract fibers, while the remaining 56% are likely activated by direct cerebropontine fibers, and further that pontine neurons are activated by both fast and slowly conducting pyramidal fibers. We here provide the first quantitative estimation of direct and collateral pontine projections from SI whisker representations in rats, with a percentage of direct cerebropontine projections well below that found in higher mammals (Allen et al 1969;Rüegg et al 1977;Tomasch 1968). Also, our observation that direct fibers have a slightly larger caliber than most collateral fibers, fits well with previous evidence of cerebropontine projections with different functional properties (Holländer et al 1968;Allen et al 1969;Rüegg et al 1977), and indicate that even at level of very small cerebrocortical regions (i.e.…”

Section: Functional Implicationssupporting

confidence: 87%

“…Schwarz and Thier 1999). The existence of both direct cerebropontine projections and indirect collateral innervation from cerebrospinal projections is well known from anatomical (Ramón y Cajal 1952;Tomasch 1969;Ugolini and Kuypers 1986;Stanfield and O'Leary 1985) and electrophysiological (Allen et al 1969(Allen et al , 1975Endo et al 1973;Rüegg et al 1977) investigations. The proportion of direct projections is known to increase along the phylogenetical scale (Tomasch 1969;Rüegg et al 1977;Oshima 1979;Ugolini and Kuypers 1986).…”

Section: Functional Implicationsmentioning

confidence: 95%

“…The existence of both direct cerebropontine projections and indirect collateral innervation from cerebrospinal projections is well known from anatomical (Ramón y Cajal 1952;Tomasch 1969;Ugolini and Kuypers 1986;Stanfield and O'Leary 1985) and electrophysiological (Allen et al 1969(Allen et al , 1975Endo et al 1973;Rüegg et al 1977) investigations. The proportion of direct projections is known to increase along the phylogenetical scale (Tomasch 1969;Rüegg et al 1977;Oshima 1979;Ugolini and Kuypers 1986). In cat, electrophysiological findings by Allen et al (1969Allen et al ( , 1975 indicate that 46% of pontine neurons are activated by collaterals of pyramidal tract fibers, while the remaining 56% are likely activated by direct cerebropontine fibers, and further that pontine neurons are activated by both fast and slowly conducting pyramidal fibers.…”

Section: Functional Implicationsmentioning

confidence: 97%

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Branching of individual somatosensory cerebropontine axons in rat: evidence of divergence

2007

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The cerebral cortex conveys major input to the granule cell layer of the cerebellar hemispheres by way of the pontine nuclei. Cerebrocortical projections terminate in multiple, widely distributed clusters in the pontine nuclei. This clustered organization is thought to provide the transition between the different organizational principles of the cerebrum and cerebellum, and indicates that parallel processing occurs at multiple sites in the pontine nuclei. At a cellular level, however, it is unknown whether individual cerebropontine neurons target pontocerebellar cells located in different clusters or not. We have employed anterograde axonal tracing and 3D computerized reconstruction techniques to characterize the branching pattern and morphology of individual cerebropontine axons from the primary somatosensory cortex (SI). Our findings show that 43% of the cerebrobulbar fibers arising from SI whisker representations provide two or three fibers entering the pontine nuclei, whereas 39% have only one fiber, and the remaining 18% do not project to the pontine nuclei. Thus, it appears that a majority of cerebropontine axons originating in SI whisker representations diverge to contact multiple, separated pontocerebellar cells. Further, 84% of the somatosensory cerebropontine fibers are collateral branches from cerebrobulbar and/or cerebrospinal parent fibers, while 16% are direct cerebropontine projections without a further descending projection. A range of thicknesses of the fibers entering the pontine nuclei were observed, with collaterals of corticobulbar fibers having the smallest diameter. Taken together, these findings may be related to previously described separate cerebropontine transmission lines with different properties.

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Section: Functional Implicationssupporting

confidence: 87%

Section: Functional Implicationsmentioning

confidence: 95%

Section: Functional Implicationsmentioning

confidence: 97%

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Branching of individual somatosensory cerebropontine axons in rat: evidence of divergence

2007

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“…Close spatial relationships among pontine terminal fields of axons that originate in different parts of the cerebral cortex may represent in part the substrate for large receptive fields of pontine neurons (Rü egg and Wiesendanger, 1975;Rü egg et al, 1977;Potter et al, 1978; see also Baker et al, 1976;Thier et al, 1988;Suzuki et al, 1990;Mihailoff et al, 1992). The degree of functional overlap among different terminal fields and convergence of input onto single pontine neurons, however, is highly dependent on the extent of dendritic arbors of pontine neurons.…”

Section: Pontine Somatotopic Mappingmentioning

confidence: 97%

Rat somatosensory cerebropontocerebellar pathways: Spatial relationships of the somatotopic map of the primary somatosensory cortex are preserved in a three-dimensional clustered pontine map

et al. 2000

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In the primary somatosensory cortex (SI), the body surface is mapped in a relatively continuous fashion, with adjacent body regions represented in adjacent cortical domains. In contrast, somatosensory maps found in regions of the cerebellar hemispheres, which are influenced by the SI through a monosynaptic link in the pontine nuclei, are discontinuous ("fractured") in organization. To elucidate this map transformation, the authors studied the organization of the first link in the SI-cerebellar pathway, the SI-pontine projection. After injecting anterograde axonal tracers into electrophysiologically defined parts of the SI, three-dimensional reconstruction and computer-graphic visualization techniques were used to analyze the spatial distribution of labeled fibers. Several target regions in the pontine nuclei were identified for each major body representation. The labeled axons formed sharply delineated clusters that were distributed in an inside-out, shell-like fashion. Upper lip and other perioral representations were located in a central core, whereas extremity and trunk representations were found more externally. The multiple clusters suggest that the pontine nuclei contain several representations of the SI map. Within each representation, the spatial relationships of the SI map are largely preserved. This corticopontine projection pattern is compatible with recently proposed principles for the establishment of subcortical topographic patterns during development. The largely preserved spatial relationships in the pontine somatotopic map also suggest that the transformation from an organized topography in SI to a fractured map in the cerebellum takes place primarily in the mossy fiber pontocerebellar projection.

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“…Finally, there is a need for physiological data. Rü egg et al (1977) investigated electrophysiological properties of pontine neurons in squirrel monkeys. Those neurons responding both to electric stimulation of postcentral somatosensory areas and peripheral natural stimuli were found to have large receptive fields and to react to joint movements, but also to various cutaneous stimuli.…”

Section: Functional Considerationsmentioning

confidence: 99%

Monkey somatosensory cerebrocerebellar pathways: Uneven densities of corticopontine neurons in different body representations of areas 3b, 1, and 2

et al. 1999

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Effects of electrical stimulation of somatosensory and motor areas of the cerebral cortex on neurones of the pontine nuclei in squirrel monkeys

Cited by 35 publications

References 8 publications

Branching of individual somatosensory cerebropontine axons in rat: evidence of divergence

Branching of individual somatosensory cerebropontine axons in rat: evidence of divergence

Rat somatosensory cerebropontocerebellar pathways: Spatial relationships of the somatotopic map of the primary somatosensory cortex are preserved in a three-dimensional clustered pontine map

Monkey somatosensory cerebrocerebellar pathways: Uneven densities of corticopontine neurons in different body representations of areas 3b, 1, and 2

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