liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Loss of sensory discrimination after median nerve injury does not decrease activation in the primary somatosensory cortex in fMRI
Department of Plastic Surgery, Hand Surgery and Burns and Department of Clinical Neurophysiology, University Hospital, Linköping, Sweden and the Department of Clinical Neurophysiology, Karolinska Hospital, Stockholm, Sweden.
Department of Clinical Neurophysiology, Karolinska Hospital, Stockholm, Sweden.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The aim of this study was to assess functional effects of median nerve injnry and regeneration on the primary somatosensory cortex in adults. Activation in the somatosensory cortex was studied in 6 injured adult men and 12 healthy volunteers with functional magnetic resonance imaging (fMRI) and somatosensory evoked potentials. Examination 15 to 55 months (mean 38 ± 18) after a total transection of the median nerve at the wrist repaired with epineural suture showed a persistent loss of two point discrimination in digit II-III and a decrease in sensory nerve conduction velocity (-29 %) and amplitude (-84 %) in the median nerve segment at the wrist. The cortical somatosensory potential evoked by electrical nerve stimulation proximal to the lesion was normal in latency and amplitude. fMRl performed during tactile stimulation of dig II-III (distal to the lesion) resulted in all patients in activation near the contralateral central sulcus (n=4, two patients and one control were excluded because of movement artifacts). The activated area was increased by 48 %relative to stimulation of the unaffected hand (p<0.05) but not significantly different from controls. It is concluded that a loss of sensory discrimination in the hand following median nerve injury is associated with a normal or even elevated activation in the somatosensory cortex as measured with fMRI during tactile stimulation.

Keyword [en]
functional magnetic resonance imaging, nerve injury, plasticity, regeneration, somatosensory
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-79483OAI: oai:DiVA.org:liu-79483DiVA: diva2:542798
Available from: 2012-08-03 Created: 2012-08-03 Last updated: 2012-08-03Bibliographically approved
In thesis
1. Peripheral and central effects of nerve regeneration: Experimental and clinical studies
Open this publication in new window or tab >>Peripheral and central effects of nerve regeneration: Experimental and clinical studies
2000 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A nerve injury in the hand often results in profound abnmmalities in sensory perception despite careful alignment and microsurgical repair in order to facilitate accurate nerve regeneration. The present experimental and clinical studies were undertaken in an attempt to functionally evaluate peripheral and central effects of nerve regeneration.

In the experimental studies the rat foot was used as a model for the human hand. Three months after neurotomy and repair a flUlctional evaluation was performed of regenerated and misrouted polymodal nociceptor C-fibers and low-threshold mechanoreceptive axons by mechanical stimulation on the foot and electrical recordings proximal to the lesion and by Evans blue albumin extravasation.

It was found that 1) functional regeneration of misrouted axons related to polymodal nociceptive units and low-threshold mechanoreceptive units is more efficient in hairy skin of the rat foot whereas only misrouted polymodal nociceptor C-fibers recover function in glabrous skin, 2) following epineural suture and repair with a silicone tube after sciatic neurotomy there is similar effect on the regeneration of polymodal C-fibers after three months, and 3) functional regeneration of C-fibers is more successful in 3-month-old than in new-born rats.

In the clinical studies the functional effects of median nerve injury and regeneration were evaluated by two-point discrimination test, electroneurography, somatosensory evoked potentials and functional magnetic resonance imaging (IMRI). A method oftMRI during tactile stimulation was developed, and the normal cortical activation during stimulation was studied in 12 healthy volunteers.

The effects of nerve injury were studied in 6 injured adult men 15-55 months after median nerve injury and repair. It was found that 1) the 2-point discrimination was > 15 mm, 2) the nerve conduction velocity and signal amplitude were decreased in the severed nerve segment, but the cortical evoked response was normal at nerve stimulation proximal to the lesion, 3) tactile stimulation of the glabrous skin of the hand in healthy volunteers caused bilateral cortical activation (fMRI) in the primary somatosensory cortex, 4) a loss of sensory discrimination in the hand after median nerve injury was associated with a normal or even elevated activation (fMRI) in the somatosensory cortex during tactile stimulation of the digit IT-m.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2000. 35 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 617
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-28041 (URN)12802 (Local ID)91-7219-574-6 (ISBN)12802 (Archive number)12802 (OAI)
Public defence
2000-03-03, Berzeliussalen, Universitetssjukhuset, Linköping, 09:15 (Swedish)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-08-03Bibliographically approved

Open Access in DiVA

No full text

Authority records BETA

Hansson, Thomas

Search in DiVA

By author/editor
Hansson, Thomas
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 44 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf