PMID- 19136299
OWN - NLM
STAT- MEDLINE
DCOM- 20090612
LR  - 20090331
IS  - 1872-8952 (Electronic)
IS  - 1388-2457 (Linking)
VI  - 120
IP  - 3
DP  - 2009 Mar
TI  - Sensory afferent inhibition within and between limbs in humans.
PG  - 610-8
LID - 10.1016/j.clinph.2008.12.003 [doi]
AB  - OBJECTIVE: To examine the distribution and inter-limb interaction of 
      short-latency afferent inhibition (SAI) in the arm and leg. METHODS: Motor evoked 
      potentials (MEPs) in distal and proximal arm, shoulder and leg muscles induced 
      with ranscranial magnetic stimulation (TMS) were conditioned by painless 
      electrical stimuli applied to the index finger (D2) and great toe (T1) at 
      interstimulus intervals (ISIs) of 15, 25-35, 80 ms (D2) and 35, 45, 55, 65 and 
      100 ms (T1) in 27 healthy human subjects. TMS was delivered over primary motor 
      cortex (M1) arm and leg areas. Electrical stimulus intensities were varied 
      between 1 and 3 times the sensory perception thresholds. We also tested effects 
      of posterior cutaneous brachial nerve (PCBN) stimulation on MEPs in arm muscles 
      at ISIs of 18 and 28 ms. RESULTS: D2 but not PCBN electrical conditioning reduced 
      MEP amplitudes in upper limb muscles at ISIs of 25 and 35 ms. SAI was more 
      pronounced in distal as compared to proximal arm muscles. Also, SAI following D2 
      stimulation increased with higher conditioning intensities. D2 stimulation did 
      not change lower limb muscles MEPs. In contrast, T1 stimulation did not induce 
      SAI in any muscles but caused MEP facilitation in a foot muscle at an ISI of 55 
      ms and in upper limb muscles at ISIs of 35 and 55 ms. Short interval 
      intracortical inhibition (SICI) and intracortical facilitation (ICF) were not 
      affected by electrical T1 conditioning. CONCLUSION: D2 stimulation causes 
      segmental SAI in upper limb muscles with a distal to proximal attenuation without 
      affecting leg muscles. In contrast, toe stimulation facilitates motor output both 
      in foot and upper arm muscles. SIGNIFICANCE: Our data suggest that cutaneo-motor 
      pathways in arms and legs are functionally organized in a different way with 
      cutaneo-motor interactions induced by toe stimulation probably relayed at a 
      thalamic level. Abnormal cutaneo-motor interactions following electrical toe 
      stimulation may serve as an electrophysiological marker of thalamic dysfunction, 
      e.g. in neurodegenerative diseases.
FAU - Bikmullina, R
AU  - Bikmullina R
AD  - Department of Neurology, University Medical Centre Hamburg-Eppendorf, 
      Martinistrasse 52, 20246 Hamburg, Germany.
FAU - Baumer, T
AU  - Baumer T
FAU - Zittel, S
AU  - Zittel S
FAU - Munchau, A
AU  - Munchau A
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20090110
PL  - Netherlands
TA  - Clin Neurophysiol
JT  - Clinical neurophysiology : official journal of the International Federation of 
      Clinical Neurophysiology
JID - 100883319
SB  - IM
MH  - Adult
MH  - Afferent Pathways/*physiology
MH  - Arm/innervation/physiology
MH  - Electric Stimulation
MH  - Evoked Potentials, Motor/*physiology
MH  - Extremities/innervation/*physiology
MH  - Female
MH  - Humans
MH  - Leg/innervation/physiology
MH  - Male
MH  - Motor Cortex/*physiology
MH  - Neural Inhibition/*physiology
MH  - Reaction Time/physiology
MH  - Sensory Thresholds/*physiology
MH  - Skin/innervation
MH  - Thalamus/physiology
MH  - Time Factors
MH  - Toes/innervation/physiology
MH  - Transcranial Magnetic Stimulation
MH  - Young Adult
EDAT- 2009/01/13 09:00
MHDA- 2009/06/13 09:00
CRDT- 2009/01/13 09:00
PHST- 2008/05/02 00:00 [received]
PHST- 2008/12/02 00:00 [revised]
PHST- 2008/12/05 00:00 [accepted]
PHST- 2009/01/13 09:00 [entrez]
PHST- 2009/01/13 09:00 [pubmed]
PHST- 2009/06/13 09:00 [medline]
AID - S1388-2457(08)01275-3 [pii]
AID - 10.1016/j.clinph.2008.12.003 [doi]
PST - ppublish
SO  - Clin Neurophysiol. 2009 Mar;120(3):610-8. doi: 10.1016/j.clinph.2008.12.003. Epub 
      2009 Jan 10.