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In motor control, the general view is still that spinal interneurons mainly contribute to reflexes and automatic movements. The question raised here is whether spinal interneurons can mediate the cortical command for independent finger movements, like a precision grip between the thumb and index finger in the macaque monkey, or if this function depends(More)
Coupling between pyramidal tract (PT) neurones and ipsilateral hindlimb motoneurones was investigated by recording from commissural interneurones interposed between them. Near maximal stimulation of either the left or right PT induced short latency EPSPs in more than 80% of 20 commissural interneurones that were monosynaptically excited by reticulospinal(More)
This review deals with a spinal interneuronal system, denoted the C3-C4 propriospinal system, which is unique in the sense that it so far represents the only spinal interneuronal system for which it has been possible to demonstrate a command mediating role for voluntary movements. The C3-C4 propriospinal neurones govern target reaching and can update the(More)
A task has been developed to investigate the ability of cats to switch the direction of an ongoing target-reaching forelimb movement with the aid of a visual cue. The cats were standing in front of two horizontal tubes (internal diameter 30 mm; shoulder level) with food. The entrances of the tubes were closed with opaque trap doors but during illumination(More)
The aim of the study was to analyse the potential contribution of excitatory and inhibitory premotor interneurones in reflex pathways from muscle afferents to actions of pyramidal tract (PT) neurones on ipsilateral hindlimb motoneurones. Disynaptic EPSPs and IPSPs evoked in motoneurones in deeply anaesthetized cats by group Ia, Ib and II muscle afferents(More)
The food-taking movement by which a cat grasps a morsel of food and brings it to the mouth is governed by interneurones in the forelimb segments (C6-Th1) and is normally controlled by the cortico- and rubrospinal tracts. It disappears reversibly when these tracts are transected in C5. The reappearance after some time is at least in part due to a(More)
Recovery of voluntary movements after partial spinal cord injury depends, in part, on a take-over of function via unlesioned pathways. Using precise forelimb movements in the cat as model, spinal pathways contributing to motor restitution have been investigated in more detail. The food-taking movement by which the cat graSPS a morsel of food with the digits(More)
We have shown previously that ipsilateral pyramidal tract (PT) neurons facilitate the actions of reticulospinal neurons on feline motoneurons (Edgley et al., 2004), which indicates that they might assist the recovery of motor functions after injuries of contralateral corticospinal neurons. Nevertheless, stimulation of ipsilateral PT fibers alone only rarely(More)
This study uses a previously described paradigm (Pettersson et al., 1997) to investigate the ability of cats to change the direction of ongoing reaching when the target is shifted sideways; the effect on the switching latency of spinal cord lesions was investigated. Large ventral lesions transecting the ventral funicle and the ventral half of the lateral(More)