TY - JOUR
T1 - Excitatory and inhibitory after-effects after repetitive magnetic transcranial stimulation (rTMS) in normal subjects
AU - Gilio, F.
AU - Conte, A.
AU - Vanacore, N.
AU - Frasca, V.
AU - Inghilleri, M.
AU - Berardelli, A.
PY - 2007/2
Y1 - 2007/2
N2 - We investigated the post-train effects of repetitive transcranial magnetic stimulation (rTMS) on motor evoked potential (MEP) size and cortical silent period (SP) duration. rTMS was delivered over the primary motor cortex in trains of 5, 10, 20, 40 and 60 stimuli in normal subjects at rest and in trains of 5, 10 and 20 stimuli during voluntary muscle contraction. The intensity of stimulation was 120% of resting motor threshold. Test MEPs were delivered at different interstimulus intervals after rTMS ended. At rest, 5 Hz trains produced an increase in the MEP size that persisted after the end of the trains. Trains of 5 stimuli produced after-effects that persisted for 0.5 s, whereas trains of 40 and 60 stimuli produced a facilitation that lasted for several seconds. 5 Hz-rTMS delivered during muscle contraction increased the SP duration during stimulation but the increase persisted for only 1 s after the train ended. The present experiments show that the after-effects of rTMS on MEP amplitude and SP duration have different time-courses. rTMS probably elicits its after-effects on excitatory and inhibitory cortical elements through different physiological mechanisms.
AB - We investigated the post-train effects of repetitive transcranial magnetic stimulation (rTMS) on motor evoked potential (MEP) size and cortical silent period (SP) duration. rTMS was delivered over the primary motor cortex in trains of 5, 10, 20, 40 and 60 stimuli in normal subjects at rest and in trains of 5, 10 and 20 stimuli during voluntary muscle contraction. The intensity of stimulation was 120% of resting motor threshold. Test MEPs were delivered at different interstimulus intervals after rTMS ended. At rest, 5 Hz trains produced an increase in the MEP size that persisted after the end of the trains. Trains of 5 stimuli produced after-effects that persisted for 0.5 s, whereas trains of 40 and 60 stimuli produced a facilitation that lasted for several seconds. 5 Hz-rTMS delivered during muscle contraction increased the SP duration during stimulation but the increase persisted for only 1 s after the train ended. The present experiments show that the after-effects of rTMS on MEP amplitude and SP duration have different time-courses. rTMS probably elicits its after-effects on excitatory and inhibitory cortical elements through different physiological mechanisms.
KW - Cortical plasticity
KW - Cortical silent period
KW - Magnetic stimulation
KW - Motor evoked potential
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U2 - 10.1007/s00221-006-0638-9
DO - 10.1007/s00221-006-0638-9
M3 - Article
C2 - 16900360
AN - SCOPUS:33846581023
VL - 176
SP - 588
EP - 593
JO - Experimental Brain Research
JF - Experimental Brain Research
SN - 0014-4819
IS - 4
ER -