Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2001-3-12
pubmed:abstractText
The present study investigated excitatory reflex receptive fields for various muscle reflex responses and reflex mediated ankle joint movements using randomised electrical stimulation of the dorsal and plantar surface of the foot in 12 healthy subjects. Eleven electrodes (0.5-cm2 cathodes) were mounted on the dorsal side and three on the plantar side of the foot. A low (1.5 times pain threshold) and a high (2.3 times pain threshold) stimulus intensity were used to elicit the reflexes. EMG signals were recorded from tibialis anterior (TA), gastrocnemius medialis (GM), soleus (SO), biceps femoris (BF), and rectus femoris (RF) muscles together with the ankle movement measured by a goniometer. The withdrawal pattern evoked from the dorsal side consisted of two separate responses with different receptive fields: (1) early EMG responses in GM and BF (50-120 ms) evoking knee flexion, probably of purely spinal origin, and (2) a late response in GM and SO (120-200 ms) that may be under supraspinal control. The ankle flexor TA was significantly activated in both time windows, but in 11 of 12 subjects its contraction was too small to cause significant dorsal flexion. In the ankle joint inversion was the most dominant movement. Stimulation of the plantar side resulted in activation of TA when stimulating the forefoot and in activation of triceps surae when stimulating the heel. These observations show that painful stimuli activate appropriate muscles depending on stimulus location to initiate the adequate withdrawal. For proximal muscles (e.g. knee flexors) the receptive field covers almost the entire foot (dorsal and plantar sides) while more distal muscles have a smaller receptive field covering only a part of the foot. This adequate withdrawal movement suggests a more refined withdrawal reflex organisation than a stereotyped flexion of all joints to avoid tissue damage.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-4819
pubmed:author
pubmed:issnType
Print
pubmed:volume
136
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
303-12
pubmed:dateRevised
2009-11-11
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Withdrawal reflex organisation to electrical stimulation of the dorsal foot in humans.
pubmed:affiliation
Laboratory for Experimental Pain Research, Center for Sensory-Motor Interaction, Aalborg University, Denmark.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't