Influence of Waveform and Current Direction on Short-Interval Intracortical Facilitation: A Paired-Pulse TMS Study
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Influence of Waveform and Current Direction on Short-Interval Intracortical Facilitation : A Paired-Pulse TMS Study . / Delvendahl, Igor; Lindemann, Hannes; Jung, Nikolai H; Pechmann, Astrid; Siebner, Hartwig R; Mall, Volker.
In: Brain Stimulation, Vol. 7, No. 1, 2014, p. 49-58.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Influence of Waveform and Current Direction on Short-Interval Intracortical Facilitation
T2 - A Paired-Pulse TMS Study
AU - Delvendahl, Igor
AU - Lindemann, Hannes
AU - Jung, Nikolai H
AU - Pechmann, Astrid
AU - Siebner, Hartwig R
AU - Mall, Volker
N1 - Copyright © 2014 Elsevier Inc. All rights reserved.
PY - 2014
Y1 - 2014
N2 - BACKGROUND: Transcranial magnetic stimulation (TMS) of the human primary motor hand area (M1-HAND) can produce multiple descending volleys in fast-conducting corticospinal neurons, especially so-called indirect waves (I-waves) resulting from trans-synaptic excitation. Facilitatory interaction between these I-waves can be studied non-invasively using a paired-pulse paradigm referred to as short-interval intracortical facilitation (SICF).OBJECTIVE/HYPOTHESIS: We examined whether SICF depends on waveform and current direction of the TMS pulses.METHODS: In young healthy volunteers, we applied single- and paired-pulse TMS to M1-HAND. We probed SICF by pairs of monophasic or half-sine pulses at suprathreshold stimulation intensity and inter-stimulus intervals (ISIs) between 1.0 and 5.0 ms. For monophasic paired-pulse stimulation, both pulses had either a posterior-anterior (PA) or anterior-posterior (AP) current direction (AP-AP or PA-PA), whereas current direction was reversed between first and second pulse for half-sine paired-pulse stimulation (PA-AP and AP-PA).RESULTS: Monophasic AP-AP stimulation resulted in stronger early SICF at 1.4 ms relative to late SICF at 2.8 and 4.4 ms, whereas monophasic PA-PA stimulation produced SICF of comparable size at all three peaks. With half-sine stimulation the third SICF peak was reduced for PA-AP current orientation compared with AP-PA.CONCLUSION: SICF elicited using monophasic as well as half-sine pulses is affected by current direction at clearly suprathreshold intensities. The impact of current orientation is stronger for monophasic compared with half-sine pulses. The direction-specific effect of paired-pulse TMS on the strength of early versus late SICF shows that different cortical circuits mediate early and late SICF.
AB - BACKGROUND: Transcranial magnetic stimulation (TMS) of the human primary motor hand area (M1-HAND) can produce multiple descending volleys in fast-conducting corticospinal neurons, especially so-called indirect waves (I-waves) resulting from trans-synaptic excitation. Facilitatory interaction between these I-waves can be studied non-invasively using a paired-pulse paradigm referred to as short-interval intracortical facilitation (SICF).OBJECTIVE/HYPOTHESIS: We examined whether SICF depends on waveform and current direction of the TMS pulses.METHODS: In young healthy volunteers, we applied single- and paired-pulse TMS to M1-HAND. We probed SICF by pairs of monophasic or half-sine pulses at suprathreshold stimulation intensity and inter-stimulus intervals (ISIs) between 1.0 and 5.0 ms. For monophasic paired-pulse stimulation, both pulses had either a posterior-anterior (PA) or anterior-posterior (AP) current direction (AP-AP or PA-PA), whereas current direction was reversed between first and second pulse for half-sine paired-pulse stimulation (PA-AP and AP-PA).RESULTS: Monophasic AP-AP stimulation resulted in stronger early SICF at 1.4 ms relative to late SICF at 2.8 and 4.4 ms, whereas monophasic PA-PA stimulation produced SICF of comparable size at all three peaks. With half-sine stimulation the third SICF peak was reduced for PA-AP current orientation compared with AP-PA.CONCLUSION: SICF elicited using monophasic as well as half-sine pulses is affected by current direction at clearly suprathreshold intensities. The impact of current orientation is stronger for monophasic compared with half-sine pulses. The direction-specific effect of paired-pulse TMS on the strength of early versus late SICF shows that different cortical circuits mediate early and late SICF.
KW - Adult
KW - Evoked Potentials, Motor
KW - Female
KW - Humans
KW - Male
KW - Motor Cortex
KW - Transcranial Magnetic Stimulation
KW - Young Adult
U2 - 10.1016/j.brs.2013.08.002
DO - 10.1016/j.brs.2013.08.002
M3 - Journal article
C2 - 24075915
VL - 7
SP - 49
EP - 58
JO - Brain Stimulation
JF - Brain Stimulation
SN - 1935-861X
IS - 1
ER -
ID: 138557686