TY - JOUR
T1 - BOLD-fMRI response vs. transcranial magnetic stimulation (TMS) pulse-train length
T2 - Testing for linearity
AU - Bohning, Daryl E.
AU - Shastri, Ananda
AU - Lomarev, Mikhail P.
AU - Lorberbaum, Jeffrey P.
AU - Nahas, Ziad
AU - George, Mark S.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2003/3/1
Y1 - 2003/3/1
N2 - Purpose: To measure motor and auditory cortex blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) response to impulse-like transcranial magnetic stimulation (TMS) pulses as a function of train length. Materials and Methods: Interleaved with fMRI at 1.5 T, TMS pulses 0.3-msec long were applied at 1 Hz to the motor cortex area for thumb. Six subjects were studied in a TR = 1 second session administering trains of 1, 2, 4, 8, and 16 pulses, and a TR = 3 seconds session administering trains of 1, 2, 4, 8, 16, and 24 pulses. A simple hemodynamic model with finite recovery and saturation was used to quantitatively characterize the BOLD-fMRI response as a function of train length. Results: In both the activations directly induced in motor cortex by TMS and the indirect activations in auditory cortex caused by the sound of the TMS coil firing, the BOLD-fMRI responses to multiple pulses were well described by a summation of single-pulse impulse functions. Conclusion: Up to 24 discrete pulses, BOLD-fMRI response to 1 Hz TMS in both motor cortex and auditory cortex were consistent with a linear increase in amplitude and length with train length, possibly suggesting that stimuli of 1 to 2 seconds may be too long to represent impulses.
AB - Purpose: To measure motor and auditory cortex blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) response to impulse-like transcranial magnetic stimulation (TMS) pulses as a function of train length. Materials and Methods: Interleaved with fMRI at 1.5 T, TMS pulses 0.3-msec long were applied at 1 Hz to the motor cortex area for thumb. Six subjects were studied in a TR = 1 second session administering trains of 1, 2, 4, 8, and 16 pulses, and a TR = 3 seconds session administering trains of 1, 2, 4, 8, 16, and 24 pulses. A simple hemodynamic model with finite recovery and saturation was used to quantitatively characterize the BOLD-fMRI response as a function of train length. Results: In both the activations directly induced in motor cortex by TMS and the indirect activations in auditory cortex caused by the sound of the TMS coil firing, the BOLD-fMRI responses to multiple pulses were well described by a summation of single-pulse impulse functions. Conclusion: Up to 24 discrete pulses, BOLD-fMRI response to 1 Hz TMS in both motor cortex and auditory cortex were consistent with a linear increase in amplitude and length with train length, possibly suggesting that stimuli of 1 to 2 seconds may be too long to represent impulses.
KW - BOLD response linearity
KW - Motor cortex
KW - Train length
KW - Transcranial magnetic stimulation (TMS)
KW - fMRI
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U2 - 10.1002/jmri.10271
DO - 10.1002/jmri.10271
M3 - Article
C2 - 12594717
AN - SCOPUS:0037373426
SN - 1053-1807
VL - 17
SP - 279
EP - 290
JO - Journal of Magnetic Resonance Imaging
JF - Journal of Magnetic Resonance Imaging
IS - 3
ER -