Document Detail

Contribution of intrinsic properties and synaptic inputs to motoneuron discharge patterns: a simulation study.
MedLine Citation:
PMID:  22031773     Owner:  NLM     Status:  MEDLINE    
Motoneuron discharge patterns reflect the interaction of synaptic inputs with intrinsic conductances. Recent work has focused on the contribution of conductances mediating persistent inward currents (PICs), which amplify and prolong the effects of synaptic inputs on motoneuron discharge. Certain features of human motor unit discharge are thought to reflect a relatively stereotyped activation of PICs by excitatory synaptic inputs; these features include rate saturation and de-recruitment at a lower level of net excitation than that required for recruitment. However, PIC activation is also influenced by the pattern and spatial distribution of inhibitory inputs that are activated concurrently with excitatory inputs. To estimate the potential contributions of PIC activation and synaptic input patterns to motor unit discharge patterns, we examined the responses of a set of cable motoneuron models to different patterns of excitatory and inhibitory inputs. The models were first tuned to approximate the current- and voltage-clamp responses of low- and medium-threshold spinal motoneurons studied in decerebrate cats and then driven with different patterns of excitatory and inhibitory inputs. The responses of the models to excitatory inputs reproduced a number of features of human motor unit discharge. However, the pattern of rate modulation was strongly influenced by the temporal and spatial pattern of concurrent inhibitory inputs. Thus, even though PIC activation is likely to exert a strong influence on firing rate modulation, PIC activation in combination with different patterns of excitatory and inhibitory synaptic inputs can produce a wide variety of motor unit discharge patterns.
Randall K Powers; Sherif M Elbasiouny; W Zev Rymer; C J Heckman
Related Documents :
24591593 - Blood-spinal cord barrier disruption contributes to early motor-neuron degeneration in ...
5091163 - Effect of oxotremorine on the acetylcholine content of whole brain and various brain re...
18220753 - The heterogeneity of amyotrophic lateral sclerosis: a possible explanation of treatment...
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-10-26
Journal Detail:
Title:  Journal of neurophysiology     Volume:  107     ISSN:  1522-1598     ISO Abbreviation:  J. Neurophysiol.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-01-17     Completed Date:  2012-05-22     Revised Date:  2013-06-27    
Medline Journal Info:
Nlm Unique ID:  0375404     Medline TA:  J Neurophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  808-23     Citation Subset:  IM    
Dept. of Physiology and Biophysics, Univ. of Washington, Seattle, WA 98195, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Action Potentials / physiology
Axons / physiology
Computer Simulation*
Dendrites / physiology
Models, Neurological*
Motor Neurons / physiology*
Recruitment, Neurophysiological / physiology
Synapses / physiology*
Synaptic Transmission / physiology
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Enhanced propriospinal excitation from hand muscles to wrist flexors during reach-to-grasp in humans...
Next Document:  Spatiotemporal analysis of electrically evoked activity in the chicken optic tectum - a VSDI study.