Metachronal propagation of motoneurone burst activation in isolated spinal cord of newborn rat.
The Journal of Physiology. 2005-10-01; 568(2): 583-597
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1. J Physiol. 2005 Oct 15;568(Pt 2):583-97. Epub 2005 Aug 4.
Metachronal propagation of motoneurone burst activation in isolated spinal cord
of newborn rat.
(1)CNRS UMR 5543, Université de Bordeaux II, Zone nord Bat 2, France.
Adequate locomotor and postural activity in mammals results from the coordinated
activation of assemblies of spinal cord networks. In order to assess the global
functioning of spinal circuitry, multisite recordings were made from an isolated
spinal cord preparation of the newborn rat. Motor activity, elicited in a
disinhibited network by bath-applying strychnine (glycinergic blocker) and
bicuculline (GABAergic blocker), consisted of slow spontaneous bursting. Under
these conditions, the recorded bursts were coordinated in 1: 1 relationships at
all segmental levels. For each cycle, a leading segment initiated the activity
that then propagated in a metachronal way through adjacent segments along the
length of spinal cord. There was both regional non-linearity and directional
asymmetry in this burst propagation: motor bursts propagated most rapidly in the
thoracic spinal cord and the rostro-caudal wave travelled faster than the
caudo-rostral one. Propagation involved both long projecting fibres and local
intersegmental connections. These results suggest that the mammalian spinal cord
contains propriospinal pathways subserving a metachronal transmission of motor
information and that normally it may be involved in coordinating various parts of
the body. The simple model developed here could be useful in unravelling more
general mechanisms of neuronal circuit coupling.
PMID: 16081478 [Indexed for MEDLINE]