PMID- 16497712
OWN - NLM
STAT- MEDLINE
DCOM- 20060808
LR  - 20220309
IS  - 0022-3751 (Print)
IS  - 1469-7793 (Electronic)
IS  - 0022-3751 (Linking)
VI  - 572
IP  - Pt 3
DP  - 2006 May 1
TI  - Magnetic stimulation of human premotor or motor cortex produces interhemispheric 
      facilitation through distinct pathways.
PG  - 857-68
AB  - We explored interhemispheric facilitation (IHF) between (a) left and right 
      primary motor cortex (M1) and (b) left dorsal premotor (dPM) and right M1 in 20 
      right-handed healthy human subjects using a paired pulse transcranial magnetic 
      stimulation (TMS) protocol. A conditioning TMS pulse (CP) applied to left M1 or 
      dPM with an intensity of 80% and 60% active motor threshold (CP(80%AMT) and 
      CP(60%AMT), respectively) was followed by a test pulse (TP) over right M1 induced 
      by anterior-posterior- or posterior-anterior- (TP(AP), TP(PA)) directed currents 
      in the brain at interstimulus intervals (ISIs) of 3-8 and 10 ms. EMG was recorded 
      from left first dorsal interosseous muscle. In the main experimental condition 
      IHF was evoked by CP(80%AMT) over left M1 and TPAP at ISIs of 6 and 8 ms. The 
      same CP(80%AMT) produced IHF at an ISI of 8 ms when applied over left dPM but 
      only with TP(PA). In addition, when CP(60%AMT) was given to M1, IHF was present 
      at an ISI of 6 ms (but not 8 ms) when followed by TP(PA), indicating that IHF 
      elicited over dPM was not caused by current spread of the conditioning pulse to 
      M1. We conclude that IHF can be induced differentially by conditioning M1 and dPM 
      using subthreshold CP. These facilitatory interactions depended on the intensity 
      and ISI of the CP as well as the current flow direction of the TP. We suggest 
      that not only do the CPs activate separate anatomical pathways but also that 
      these pathways project to different populations ofinterneurons in the receiving 
      M1. These may correspond to elements involved in the generation of I3 and I1 
      waves, respectively.
FAU - Baumer, Tobias
AU  - Baumer T
AD  - Department of Neurology, University Medical Centre Hamburg-Eppendorf, Germany. 
      baeumer@uke.uni-hamburg.de
FAU - Bock, Franka
AU  - Bock F
FAU - Koch, Giacomo
AU  - Koch G
FAU - Lange, Rudiger
AU  - Lange R
FAU - Rothwell, John C
AU  - Rothwell JC
FAU - Siebner, Hartwig R
AU  - Siebner HR
FAU - Munchau, Alexander
AU  - Munchau A
LA  - eng
GR  - G0500258/MRC_/Medical Research Council/United Kingdom
PT  - Clinical Trial
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - J Physiol
JT  - The Journal of physiology
JID - 0266262
SB  - IM
MH  - Adult
MH  - Brain Mapping
MH  - Evoked Potentials, Motor/*physiology
MH  - Female
MH  - Functional Laterality/*physiology
MH  - Humans
MH  - Long-Term Potentiation/*physiology
MH  - Male
MH  - Motor Cortex/*physiology
MH  - Neural Pathways/*physiology
MH  - Transcranial Magnetic Stimulation/*methods
PMC - PMC1780006
EDAT- 2006/02/25 09:00
MHDA- 2006/08/09 09:00
PMCR- 2007/05/01
CRDT- 2006/02/25 09:00
PHST- 2006/02/25 09:00 [pubmed]
PHST- 2006/08/09 09:00 [medline]
PHST- 2006/02/25 09:00 [entrez]
PHST- 2007/05/01 00:00 [pmc-release]
AID - jphysiol.2006.104901 [pii]
AID - 10.1113/jphysiol.2006.104901 [doi]
PST - ppublish
SO  - J Physiol. 2006 May 1;572(Pt 3):857-68. doi: 10.1113/jphysiol.2006.104901.