PMID- 18499727
OWN - NLM
STAT- MEDLINE
DCOM- 20081027
LR  - 20211020
IS  - 1469-7793 (Electronic)
IS  - 0022-3751 (Print)
IS  - 0022-3751 (Linking)
VI  - 586
IP  - 14
DP  - 2008 Jul 15
TI  - Intracortical modulation of cortical-bulbar responses for the masseter muscle.
PG  - 3385-404
LID - 10.1113/jphysiol.2008.153288 [doi]
AB  - Short interval intracortical inhibition (SICI) and intracortical facilitation 
      (ICF) were evaluated in the masseter muscles of 12 subjects and the cortical 
      silent period (SP) in nine subjects. Motor evoked potentials (MEPs) were recorded 
      from contralateral (cMM) and ipsilateral (iMM) masseters, activated at 10% of 
      maximal voluntary contraction (MVC). Interstimulus intervals (ISIs) were 2 and 3 
      ms for SICI, 10 and 15 ms for ICF. TMS of the left masseteric cortex induced MEPs 
      that were larger in the cMM than the iMM; stimulation of right masseteric cortex 
      produced a similar asymmetry in response amplitude. SICI was only observed using 
      a CS intensity of 70% AMT and was equal in both cMM and iMM. SICI was stronger at 
      higher TS intensities, was abolished by muscle activation greater than 10% MVC, 
      and was unaffected by coil orientation changes. Control experiments confirmed 
      that SICI was not contaminated by any inhibitory peripheral reflexes. However, 
      ICF could not be obtained because it was masked by bilateral reflex depression of 
      masseter EMG caused by auditory input from the coil discharge. The SP was 
      bilateral and symmetric; its duration ranged from 35 to 70 ms depending on TS 
      intensity and coil orientation. We conclude that SICI is present in the cortical 
      representation of masseter muscles. The similarity of SICI in cMM and iMM 
      suggests either that a single pool of inhibitory interneurons controls ipsi- and 
      contralateral corticotrigeminal projections or that inhibition is directed to 
      bilaterally projecting corticotrigeminal fibres. Finally, the corticotrigeminal 
      projection seems to be weakly influenced by inhibitory interneurons mediating the 
      cortical SP.
FAU - Ortu, Enzo
AU  - Ortu E
AD  - Sobell Department of Motor Neuroscience and Movement Disorders, Institute of 
      Neurology, University College London, London, UK.
FAU - Deriu, Franca
AU  - Deriu F
FAU - Suppa, Antonio
AU  - Suppa A
FAU - Giaconi, Elena
AU  - Giaconi E
FAU - Tolu, Eusebio
AU  - Tolu E
FAU - Rothwell, John C
AU  - Rothwell JC
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080522
PL  - England
TA  - J Physiol
JT  - The Journal of physiology
JID - 0266262
SB  - IM
MH  - Adult
MH  - Electromyography
MH  - Evoked Potentials, Motor/*physiology
MH  - Female
MH  - Humans
MH  - Male
MH  - Masseter Muscle/*innervation/*physiology
MH  - Motor Cortex/*physiology
MH  - Muscle Contraction
PMC - PMC2538818
EDAT- 2008/05/24 09:00
MHDA- 2008/10/28 09:00
PMCR- 2009/07/15
CRDT- 2008/05/24 09:00
PHST- 2008/05/24 09:00 [pubmed]
PHST- 2008/10/28 09:00 [medline]
PHST- 2008/05/24 09:00 [entrez]
PHST- 2009/07/15 00:00 [pmc-release]
AID - jphysiol.2008.153288 [pii]
AID - 10.1113/jphysiol.2008.153288 [doi]
PST - ppublish
SO  - J Physiol. 2008 Jul 15;586(14):3385-404. doi: 10.1113/jphysiol.2008.153288. Epub 
      2008 May 22.