PMID- 18509069
OWN - NLM
STAT- MEDLINE
DCOM- 20081105
LR  - 20080813
IS  - 0022-3077 (Print)
IS  - 0022-3077 (Linking)
VI  - 100
IP  - 2
DP  - 2008 Aug
TI  - Noninvasive stimulation of human corticospinal axons innervating leg muscles.
PG  - 1080-6
LID - 10.1152/jn.90380.2008 [doi]
AB  - These studies investigated whether a single electrical stimulus over the thoracic 
      spine activates corticospinal axons projecting to human leg muscles. Transcranial 
      magnetic stimulation of the motor cortex and electrical stimulation over the 
      thoracic spine were paired at seven interstimulus intervals, and surface 
      electromyographic responses were recorded from rectus femoris, tibialis anterior, 
      and soleus. The interstimulus intervals (ISIs) were set so that the first 
      descending volley evoked by cortical stimulation had not arrived at (positive 
      ISIs), was at the same level as (0 ISI) or had passed (negative ISIs) the site of 
      activation of descending axons by the thoracic stimulation at the moment of its 
      delivery. Compared with the responses to motor cortical stimulation alone, 
      responses to paired stimuli were larger at negative ISIs but reduced at positive 
      ISIs in all three leg muscles. This depression of responses at positive ISIs is 
      consistent with an occlusive interaction in which an antidromic volley evoked by 
      the thoracic stimulation collides with descending volleys evoked by cortical 
      stimulation. The cortical and spinal stimuli activate some of the same 
      corticospinal axons. Thus it is possible to examine the excitability of lower 
      limb motoneuron pools to corticospinal inputs without the confounding effects of 
      changes occurring within the motor cortex.
FAU - Martin, P G
AU  - Martin PG
AD  - Prince of Wales Medical Research Institute, Barker Street, Randwick, Sydney, NSW 
      2031, Australia.
FAU - Butler, J E
AU  - Butler JE
FAU - Gandevia, S C
AU  - Gandevia SC
FAU - Taylor, J L
AU  - Taylor JL
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080528
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
SB  - IM
MH  - Adult
MH  - Analysis of Variance
MH  - Blood Pressure/physiology/radiation effects
MH  - Electric Stimulation/methods
MH  - Electromyography
MH  - Evoked Potentials, Motor/*physiology
MH  - Heart Rate/physiology/radiation effects
MH  - Humans
MH  - *Leg
MH  - Motor Cortex/physiology/radiation effects
MH  - Muscle Contraction/physiology
MH  - Muscle, Skeletal/*innervation
MH  - Pyramidal Tracts/*physiology/radiation effects
MH  - Reaction Time/physiology/radiation effects
MH  - Spinal Cord/physiology/radiation effects
MH  - Thorax/innervation
MH  - Time Factors
MH  - Transcranial Magnetic Stimulation/methods
EDAT- 2008/05/30 09:00
MHDA- 2008/11/06 09:00
CRDT- 2008/05/30 09:00
PHST- 2008/05/30 09:00 [pubmed]
PHST- 2008/11/06 09:00 [medline]
PHST- 2008/05/30 09:00 [entrez]
AID - 90380.2008 [pii]
AID - 10.1152/jn.90380.2008 [doi]
PST - ppublish
SO  - J Neurophysiol. 2008 Aug;100(2):1080-6. doi: 10.1152/jn.90380.2008. Epub 2008 May 
      28.