کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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3048491 | 1185083 | 2006 | 10 صفحه PDF | دانلود رایگان |

ObjectiveTo investigate the effect of local excitation of nociceptive muscle afferents on the spatial distribution of muscle activity.MethodsSurface electromyographic (EMG) signals were recorded from the upper trapezius muscle of 10 healthy volunteers with a 5 × 13 electrode grid during 90-s isometric contractions before, during, 15 and 30 min after intramuscular injection of hypertonic (painful) or isotonic (non-painful) saline. From the multi-channel EMG recordings, two-dimensional maps of root mean square and mean power frequency were obtained. The centre of gravity of the root mean square map was used to quantify global changes in the spatial distribution of muscle activity.ResultsDuring sustained contractions, average root mean square increased, average mean frequency decreased and the centre of gravity moved cranially. During experimental muscle pain, compared to before injection, the average root mean square decreased and there was a caudal shift of the centre of gravity. Fifteen minutes after the painful injection the centre of gravity returned to its original position.ConclusionsShort-term dynamic reorganization of the spatial distribution of muscle activity occurred in response to nociceptive afferent input.SignificanceThe study furnishes an extension of the pain adaptation model indicating heterogeneous inhibition of muscle activity.
Journal: Clinical Neurophysiology - Volume 117, Issue 11, November 2006, Pages 2436–2445