当前位置： SCI文献检索 > EXPERIMENTAL BRAIN RESEARCH期刊下所有文献 > Phasic modulation of short latency cutaneous excitation in flexor digitorum longus motoneurons during fictive locomotion.

Phasic modulation of short latency cutaneous excitation in flexor digitorum longus motoneurons during fictive locomotion.

Abstract：

:We examined modulation of transmission of short-latency excitation produced by distal hindlimb cutaneous input, as well as fluctuations in motoneuron membrane potential and input resistance, in flexor digitorum longus (FDL) motoneurons during fictive locomotion. Fictive stepping was induced in unaesthetized, decerebrate cats either by repetitive stimulation of the mesencephalic locomotor region (MLR) or by administration of Nialamide and 1-DOPA after low spinal section. In the MLR preparations, brief depolarizing waves occurred in FDL cells during the early flexion phase of fictive stepping, immediately after cessation of activity in extensor muscles. In some FDL cells, plateau-like depolarizations also occurred during the extensor phase. Fictive stepping induced in acutely spinalized cats by administration of 1-DOPA was slower and more variable; peak polarization in FDL motoneurons always occurred during the early flexion phase but there was usually no distinct depolarization during extension. In both types of preparation, the initial EPSP components in synaptic potentials (SP-EPSPs) produced by electrical stimulation of the cutaneous division of the superficial peroneal nerve (SP) were maximally facilitated during early flexion, coincident with the peak of background depolarization. This enhancement was manifested by an increase in the amplitude of initial SP-EPSP components or by decreased central latency of the initial EPSP components, or both. In most FDL motoneurons, input resistance decreased systematically during late flexion, coincident with relative membrane hyperpolarization. Correction of SP-EPSP amplitudes for changes in input resistance suggested that SP-EPSP facilitation persisted throughout the flexion phase. These findings are discussed with reference to modulation of cutaneous reflexes during locomotion and the possibility that excitatory last-order interneurons in particular cutaneous reflex pathways may distribute excitatory drive from the central pattern generator for locomotion to FDL alpha-motoneurons.

journal_name

Exp Brain Res

journal_title

Experimental brain research

authors

Schmidt BJ,Meyers DE,Fleshman JW,Tokuriki M,Burke RE

doi

10.1007/BF00248749

subject

Has Abstract

pub_date

1988-01-01 00:00:00

pages

568-78

issue

eissn

0014-4819

issn

1432-1106

journal_volume

pub_type

杂志文章

在线工具

Phasic modulation of short latency cutaneous excitation in flexor digitorum longus motoneurons during fictive locomotion.