Postural activity of the diaphragm is reduced in humans when respiratory demand increases

Hodges, P. W., Heijnen, I. and Gandevia, S. C. (2001) Postural activity of the diaphragm is reduced in humans when respiratory demand increases. Journal of Physiology, 537 3: 999-1008. doi:10.1111/j.1469-7793.2001.00999.x


Author Hodges, P. W.
Heijnen, I.
Gandevia, S. C.
Title Postural activity of the diaphragm is reduced in humans when respiratory demand increases
Journal name Journal of Physiology   Check publisher's open access policy
ISSN 0022-3751
Publication date 2001-01-01
Year available 2001
Sub-type Article (original research)
DOI 10.1111/j.1469-7793.2001.00999.x
Open Access Status Not yet assessed
Volume 537
Issue 3
Start page 999
End page 1008
Total pages 10
Place of publication New York
Publisher Cambridge Univ Press
Language eng
Subject 110603 Motor Control
110203 Respiratory Diseases
Abstract 1. Respiratory activity of the diaphragm and other respiratory muscles is normally co-ordinated with their other functions, such as for postural control of the trunk when the limbs move. The integration may occur by summation of two inputs at the respiratory motoneurons. The present study investigated whether postural activity of the diaphragm changed when respiratory drive increased with hypercapnoea. 2. Electromyographic (EMG) recordings of the diaphragm and other trunk muscles were made with intramuscular electrodes in 13 healthy volunteers. Under control conditions and while breathing through increased dead-space,subjects made rapid repetitive arm movements to disturb the stability of the spine for four periods each lasting 10 s, separated by 50 s. 3. End-tidal CO2, and ventilation increased for the first 60-120 s of the trial then reached a plateau. During rapid arm movement at the start of dead-space breathing, diaphragm EMG became tonic with superimposed modulation at the frequencies of respiration and arm movement. However, when the arm was moved after 60 s of hypercapnoea, the tonic diaphragm EMG during expiration and the phasic activity with arm movement were reduced or absent. Similar changes occurred for the expiratory muscle transversus abdominis, but not for the erector spinae. The mean amplitude of intra-abdominal pressure and the phasic changes with arm movement were reduced after 60 s of hypercapnoea. 4. The present data suggest that increased central respiratory drive may attenuate the postural commands reaching motoneurons. This attenuation can affect the key inspiratory and expiratory muscles and is likely to be co-ordinated at a pre-motoneuronal site.
Keyword Physiology
Intraabdominal Pressure
Drive
Coordination
Activation
Neurons
Muscles
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Health and Rehabilitation Sciences Publications
 
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Created: Mon, 13 Aug 2007, 22:45:51 EST