Change search
ReferencesLink to record
Permanent link

Direct link
Brain processing of tonic muscle pain induced by infusion of hypertonic saline.
Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
Show others and affiliations
2005 (English)In: European Journal of Pain, ISSN 1090-3801, Vol. 9, no 2, 185-194 p.Article in journal (Refereed) Published
Abstract [en]

Most of the previous studies on the effects of pain on Regional Cerebral Blood Flow (rCBF) had been done with brief cutaneous or intramuscular painful stimuli. The aim of the present study was to investigate the effect on rCBF of long lasting tonic experimental muscle pain. To this end we performed PET investigations of rCBF following tonic experimental low back pain induced by continuous intramuscular infusion of hypertonic (5%) saline (HS) with computer controlled infusion pump into the right erector spinae on L(3) level in 19 healthy volunteers. Changes in rCBF were measured with the use of (15)O labelled water during four conditions: Baseline (before start of infusion), Early Pain (4 min after start of infusion), Late Pain (20 min after start of infusion) and Post-Pain (>15 min after stop of infusion) conditions. Results of SPM analysis showed relative rCBF increase in the right insula and bilateral decrease in the temporo-parieto-occipital cortex during initial phase of painful stimulation (Early Pain) followed by activation of the medial prefrontal region and bilateral inhibition of insula, anterior cingulate and dorso-lateral prefrontal cortex mainly in ipsilateral hemisphere during Late Pain conditions. The results show that longer lasting tonic experimental muscle pain elicited by i.m infusion of HS results in decreases rather than increases in rCBF. Possible explanations for differences found in rCBF during tonic hypertonic saline-induced experimental muscle pain as compared with previous findings are discussed.

Place, publisher, year, edition, pages
2005. Vol. 9, no 2, 185-194 p.
Keyword [en]
Adult, Brain/*physiopathology/*radionuclide imaging, Case-Control Studies, Cerebrovascular Circulation/*physiology, Humans, Infusions; Parenteral, Injections; Intramuscular, Male, Muscle Tonus/drug effects/physiology, Muscle; Skeletal/drug effects/physiopathology, Pain/chemically induced/*physiopathology/radionuclide imaging, Positron-Emission Tomography, Saline Solution; Hypertonic/administration & dosage
URN: urn:nbn:se:umu:diva-16964DOI: 10.1016/j.ejpain.2004.05.003PubMedID: 15737811OAI: diva2:156637
Available from: 2007-10-23 Created: 2007-10-23 Last updated: 2009-11-18Bibliographically approved
In thesis
1. Brain processing of experimental muscle pain and its interrelation with proprioception and muscle fatigue: positron emission tomography study
Open this publication in new window or tab >>Brain processing of experimental muscle pain and its interrelation with proprioception and muscle fatigue: positron emission tomography study
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Chronic muscle pain is a significant medical and social problem and better understanding of the pathophysiological mechanisms involved is an important requirement for further development of diagnostics, treatment and rehabilitation methods. Experimental imaging studies have investigated functional neuroanatomy of different pain components. However, several aspects of brain mechanisms underlying brain processing of muscle pain remain unclear.

The general goal of the present thesis was to study functional brain anatomy of systems underlying perception of muscle pain, processing of proprioceptive information and maintenance of fatiguing muscle contractions with an emphasize on their possible interrelations.

Four series of experiment were carried out. Using an injection of hypertonic saline (HS) into the m. triceps to induce pain comparable with clinical muscle pain a significant activation of insula and putamen as well as decrease of activity in the temporal and occipital cortex in comparison with control stimulation were revealed. An advanced model of prolonged muscle pain were provided by the infusion of the HS during 20 minutes into m. erector spinae A complex dynamics of brain activity during the habituation to nociceptive stimulation was shown: initial activation of insula changed to decrease of activity in this and several other cortical areas. A conjunction analysis identified activations jointly significant in both experiments (despite localization of HS nociceptive stimulation) in the right insula, occipital and left parietal cortical areas. The study of brain activity in response to different modalities of prorioceptive inputs – passive movements, kinesthetic illusions and muscle vibration showed corresponding different patterns of activation in motor and somatosenory areas and temporal areas. Finally, the study of sustained isometric muscle contractions of various force levels and durations revealed that muscle fatigue is associated with contralateral activation of the motor and somatosensory areas and temporal areas and bilateral activation in the supplementary motor areas and cingular cortex, indicating that increased efforts needed to maintain required force and its eventual breakdown with fatigue might induce activation of additional cortical areas. Analysis of data obtained in all experimental series revealed that insula, secondary somatosensory and auditory areas are activated during both perception of muscle pain and processing of somatosensory afferentation.

In conclusion, this thesis has elucidated brain processing of muscle pain showing distributed, bilateral patterns comprised of activated structures predominantly attributed to the medial pain system and deactivated structures. Furthermore, initial and late phases of tonic muscle pain are associated with different brain reactions, namely initial activation of the insula followed by a significant bilateral decrease of activity at the late stage. Area of brain cortex located near lateral sulcus and comprised of secondary somatosensory cortex, posterior part of the insula and adjacent auditory cortex is engaged in the perception of muscle pain and processing of somatosensory afferentation as well as maintenance of fatiguing muscle contractions.

72 p.
Experimental muscle pain, Hypertonic saline, Kinesthesia, Proprioception, Movement, Vibration, Muscle fatigue, Brain, Imaging, Positron emission tomography, Regional cerebral blood flow
urn:nbn:se:umu:diva-570 (URN)
Public defence
2005-09-09, Stora föreläsningssalen, Arbetslivsinstitutet Umeå, 10:00 (English)
Available from: 2005-08-23 Created: 2005-08-23 Last updated: 2009-11-18Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed
By organisation
Sports Medicine
In the same journal
European Journal of Pain

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 42 hits
ReferencesLink to record
Permanent link

Direct link