PMID- 18074124
OWN - NLM
STAT- MEDLINE
DCOM- 20080801
LR  - 20211020
IS  - 1432-1106 (Electronic)
IS  - 0014-4819 (Linking)
VI  - 186
IP  - 3
DP  - 2008 Apr
TI  - Reduced intracortical inhibition during the foreperiod of a warned reaction time 
      task.
PG  - 385-92
AB  - Reaction time (RT) is shortened when the response signal is preceded by a warning 
      signal, a finding that has been attributed to response preparation during the 
      foreperiod between the warning and response signals. Research suggests an 
      increased excitability of cortical movement representations associated with 
      response preparation during the foreperiod of a warned RT task (Davranche et al. 
      in Eur J Neurosci 25:3766-3774, 2007). However when the foreperiod duration is 
      short and constant, the motor evoked potential (MEP) amplitude elicited by 
      transcranial magnetic stimulation (TMS) during the foreperiod is suppressed 
      (Touge et al. in Clin Neurophysiol 111:1216-1226, 1998), suggesting a competing 
      inhibitory process. Three experiments measured MEP amplitude and intracortical 
      inhibition during the foreperiod of a warned RT task in which the response was a 
      flexion of the right index finger. Experiments 1 and 2 measured short-interval 
      intracortical inhibition (SICI) with paired TMS pulses separated by 
      inter-stimulus intervals (ISIs) of 3 (SICI(3)) and 1.5 ms (SICI(1.5)), 
      respectively. Experiment 3 measured long-interval intracortical inhibition (LICI) 
      with paired TMS pulses with an ISI of 100 ms (LICI(100)). In all experiments MEP 
      amplitude was smaller in the warned condition than in the unwarned condition. 
      There was less SICI(3) in the warned condition than in the unwarned condition 
      (Experiment 1) whereas SICI(1.5) was similar in both conditions (Experiment 2). 
      There was less LICI(100) in the warned condition than in the unwarned condition 
      (Experiment 3). The intracortical inhibitory processes measured here cannot 
      explain the suppression of MEP amplitude in the warned condition. We propose that 
      the suppression of MEP amplitude is the result of an inhibitory mechanism, which 
      acts on primary motor cortex to prevent premature response during the foreperiod.
FAU - Sinclair, Craig
AU  - Sinclair C
AD  - School of Psychology, The University of Western Australia, Crawley, WA, 6009, 
      Australia. sinclc01@student.uwa.edu.au
FAU - Hammond, Geoffrey R
AU  - Hammond GR
LA  - eng
PT  - Journal Article
DEP - 20071212
PL  - Germany
TA  - Exp Brain Res
JT  - Experimental brain research
JID - 0043312
SB  - IM
MH  - Cerebral Cortex/*physiology
MH  - Electromyography
MH  - Electrophysiology/methods
MH  - Evoked Potentials, Motor
MH  - Functional Laterality
MH  - Humans
MH  - Muscle, Skeletal/innervation/physiology
MH  - Neural Inhibition/*physiology
MH  - Photic Stimulation
MH  - Reaction Time/*physiology
MH  - Time Factors
MH  - Transcranial Magnetic Stimulation
EDAT- 2007/12/13 09:00
MHDA- 2008/08/02 09:00
CRDT- 2007/12/13 09:00
PHST- 2007/10/23 00:00 [received]
PHST- 2007/11/27 00:00 [accepted]
PHST- 2007/12/13 09:00 [pubmed]
PHST- 2008/08/02 09:00 [medline]
PHST- 2007/12/13 09:00 [entrez]
AID - 10.1007/s00221-007-1241-4 [doi]
PST - ppublish
SO  - Exp Brain Res. 2008 Apr;186(3):385-92. doi: 10.1007/s00221-007-1241-4. Epub 2007 
      Dec 12.