PMID- 15649986
OWN - NLM
STAT- MEDLINE
DCOM- 20050624
LR  - 20181113
IS  - 0022-3751 (Print)
IS  - 1469-7793 (Electronic)
IS  - 0022-3751 (Linking)
VI  - 563
IP  - Pt 3
DP  - 2005 Mar 15
TI  - Interactions between long latency afferent inhibition and interhemispheric 
      inhibitions in the human motor cortex.
PG  - 915-24
AB  - Various inhibitory pathways exist in the human brain which are crucial in 
      modulating motor cortex output and they can be investigated non-invasively using 
      transcranial magnetic stimulation. Interhemispheric inhibition (IHI) is one form 
      of cortical inhibition. It can be elicited by stimulation of the opposite motor 
      cortex at interstimulus intervals (ISIs) of 10 ms (IHI10) or 40 ms (IHI40) and 
      inhibitions at these intervals are probably mediated by different mechanisms. 
      Peripheral sensory stimulation can also inhibit the motor cortex. Median nerve 
      stimulation produces long latency afferent inhibition (LAI) at ISI 200 ms. LAI 
      inhibits another form of cortical inhibition known as long interval intracortical 
      inhibition (LICI) and a study that examined the interaction between IHI10 and 
      LICI hypothesized that they are mediated by an overlapping population of 
      inhibitory neurones. We tested this hypothesis by examining the interaction 
      between IHI10, IHI40 and LAI. With increasing test MEP amplitude LAI, IHI10 and 
      IHI40 all decreased. There was no correlation between the strength of LAI, IHI10 
      and IHI40. In the presence of LAI, IHI10 was slightly but significantly reduced 
      compared to IHI10 alone. There was no correlation between the reduction in IHI10 
      in the presence of LAI and the strength of LAI or IHI10. In the presence of LAI, 
      IHI40 was significantly reduced compared to IHI40 alone. LAI produced a greater 
      decrease in IHI40 than in IHI10. The decrease in IHI40 in the presence of LAI 
      strongly correlated with the strength of LAI but not with the strength of IHI40. 
      Reducing the strength of LAI, IHI10 and IHI40 still resulted in similar 
      interaction between IHI10 and LAI but markedly decreased the effect of LAI on 
      IHI40. We conclude that LAI and IHI10 do not directly inhibit each other but LAI 
      probably inhibits IHI40. LICI is more likely to be related to IHI40 than to 
      IHI10.
FAU - Kukaswadia, Sadiya
AU  - Kukaswadia S
AD  - Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research 
      Institute, University Health Network, University of Toronto, Ontario, Canada.
FAU - Wagle-Shukla, Aparna
AU  - Wagle-Shukla A
FAU - Morgante, Francesca
AU  - Morgante F
FAU - Gunraj, Carolyn
AU  - Gunraj C
FAU - Chen, Robert
AU  - Chen R
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20050113
PL  - England
TA  - J Physiol
JT  - The Journal of physiology
JID - 0266262
SB  - IM
MH  - Adult
MH  - Afferent Pathways/*physiology
MH  - Evoked Potentials, Motor/*physiology
MH  - Female
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Motor Cortex/*physiology
MH  - Nerve Net/*physiology
MH  - Neural Inhibition/*physiology
MH  - Neural Pathways/*physiology
MH  - Reaction Time/*physiology
PMC - PMC1665612
EDAT- 2005/01/15 09:00
MHDA- 2005/06/25 09:00
PMCR- 2006/03/15
CRDT- 2005/01/15 09:00
PHST- 2005/01/15 09:00 [pubmed]
PHST- 2005/06/25 09:00 [medline]
PHST- 2005/01/15 09:00 [entrez]
PHST- 2006/03/15 00:00 [pmc-release]
AID - jphysiol.2004.080010 [pii]
AID - 10.1113/jphysiol.2004.080010 [doi]
PST - ppublish
SO  - J Physiol. 2005 Mar 15;563(Pt 3):915-24. doi: 10.1113/jphysiol.2004.080010. Epub 
      2005 Jan 13.