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A survey of spinal collateral actions of feline ventral spinocerebellar tract neurons
Author(s) -
Geborek P.,
Nilsson E.,
Bolzoni F.,
Jankowska E.
Publication year - 2013
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12060
Subject(s) - inhibitory postsynaptic potential , neuroscience , excitatory postsynaptic potential , postsynaptic potential , renshaw cell , spinal cord , interneuron , axon , pyramidal tracts , cerebellum , motor neuron , biology , anatomy , receptor , biochemistry
The aim of this study was to identify spinal target cells of spinocerebellar neurons, in particular the ventral spinocerebellar tract ( VSCT ) neurons, giving off axon collaterals terminating within the lumbosacral enlargement. Axons of spinocerebellar neurons were stimulated within the cerebellum while searching for most direct synaptic actions on intracellularly recorded hindlimb motoneurons and interneurons. In motoneurons the dominating effects were inhibitory [inhibitory postsynaptic potentials ( IPSP s) in 67% and excitatory postsynaptic potentials ( EPSP s) in 17% of motoneurons]. Latencies of most IPSP s indicated that they were evoked disynaptically and mutual facilitation between these IPSP s and disynaptic IPSP s evoked by group Ia afferents from antagonist muscles and group Ib and II afferents from synergists indicated that they were relayed by premotor interneurons in reflex pathways from muscle afferents. Monosynaptic EPSP s from the cerebellum were accordingly found in Ia inhibitory interneurons and intermediate zone interneurons with input from group I and II afferents but only oligosynaptic EPSP s in motoneurons. Monosynaptic EPSP s following cerebellar stimulation were also found in some VSCT neurons, indicating coupling between various spinocerebellar neurons. The results are in keeping with the previously demonstrated projections of VSCT neurons to the contralateral ventral horn, showing that VSCT neurons might contribute to motor control at a spinal level. They might thus play a role in modulating spinal activity in advance of any control exerted via the cerebellar loop.