Effects on the Ventral Spinocerebellar Tract Neurones from Deiters' Nucleus and the Medial Longitudinal Fascicle in the Cat

Authors

  • F. Baldissera,

    1. Department of Physiology, University of Göteborg, Sweden
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    • 1

      Lab. di Biologia Spaziale del CNR, Via Mario Bianco 9, 20131 Milano, Italy.

  • W. J. Roberts

    1. Department of Physiology, University of Göteborg, Sweden
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    • 2

      Neurological Sciences Institute, Good Samaritan Hospital and Medical Center, 1015 N.W. 22nd Avenue, Portland, Oregon 97210, U.S.A.


Abstract

Effects from the vestibulospinal tract (VST) and from fibres descending in the medial longitudinal fascicle (MLF) on the cells of origin of the ventral spinocerebellar tract (VSCT) have been studied with intracellular recording. Out of 110 VSCT neurones, the VST evoked monosynaptic EPSPs in 27, di- or polysynaptic EPSPs in 56 and disynaptic lPSPs in 26. In 93 tested VSCT cells, MLF stimulation evoked monosynaptic EPSPs in 26, monosynaptic IPSPs in 2, di- or polysynaptic EPSPs in 25 and disynaptic IPSPs in 21, Convergence of monosynaptic EPSPs from VST and MLF was found in a small proportion of cells whereas the two descending pathways evoked reciprocal effects in another small group of neurones. Convergence of monosynaptic EPSPs from VST or MLF and from group 1 afferents was also modest. In 9 VSCT neurones there was convergence of monosynaptic excitation and disynaptic inhibition from the vestibulospinal tract and the same pattern from MLF was recorded in 9 neurones. The results are discussed in view of the hypothesis that VSCT neurones carry information on the interneuronal transmission in the spinal cord.

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