TY - JOUR
T1 - Effects of repetition rate of electric stimulation on MEG and fMRI signals
AU - Iramina, Keiji
AU - Kamei, Hirotake
AU - Yumoto, Masato
AU - Ueno, Shoogo
N1 - Funding Information:
Manuscript received February 5, 2001. This work was supported in part by the Grant 12002002 from the Ministry of Education Science and Culture, Japan. K. Iramina, H. Kamei, S. Uemo are with the Department of Biomedical Engineering, University of Tokyo, Tokyo 113-0033 Japan (e-mail: {iramina; kamei; ueno}@medes.m.u-tokyo.ac.jp). M. Yumoto is with the University Hospital, University of Tokyo, Tokyo 113-8655 Japan (e-mail: yumoto-tky@umin.ac.jp). Publisher Item Identifier S 0018-9464(01)07118-7.
PY - 2001/7
Y1 - 2001/7
N2 - This study focuses on the physiological responses of somatosensory stimulation using magnetoencephalography (MEG) and functional MRI (fMRI). To investigate the relationship between neural activity and hemodynamic responses, the effect of the stimulus rate of electrical stimulation to the right thumb was investigated. In order to evaluate the blood oxygenation level dependent (BOLD) effects, signal power was calculated. The signal power is the integrated value from the beginning of the stimulation to the end of the sustained response, the point at which the signal recovers to the baseline. The signal power of fMRI and the dipole moment of MEG responses were compared. The MEG signals were measured using a 122-channel whole head SQUID system. When the stimulus frequencies were changed from 0.5 Hz to 10 Hz, the dipole moments of the M20 and M30 components of MEG signals were the largest at 1 Hz and 2Hz, respectively. A maximum signal power of fMRI occurs at a frequency higher than 2 Hz, approximately at 3 Hz or 5 Hz, and then decreases progressively. These results are in agreement with a previous positron emission tomography (PET) experiment; however, they do not concur with this MEG experiment.
AB - This study focuses on the physiological responses of somatosensory stimulation using magnetoencephalography (MEG) and functional MRI (fMRI). To investigate the relationship between neural activity and hemodynamic responses, the effect of the stimulus rate of electrical stimulation to the right thumb was investigated. In order to evaluate the blood oxygenation level dependent (BOLD) effects, signal power was calculated. The signal power is the integrated value from the beginning of the stimulation to the end of the sustained response, the point at which the signal recovers to the baseline. The signal power of fMRI and the dipole moment of MEG responses were compared. The MEG signals were measured using a 122-channel whole head SQUID system. When the stimulus frequencies were changed from 0.5 Hz to 10 Hz, the dipole moments of the M20 and M30 components of MEG signals were the largest at 1 Hz and 2Hz, respectively. A maximum signal power of fMRI occurs at a frequency higher than 2 Hz, approximately at 3 Hz or 5 Hz, and then decreases progressively. These results are in agreement with a previous positron emission tomography (PET) experiment; however, they do not concur with this MEG experiment.
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U2 - 10.1109/20.951347
DO - 10.1109/20.951347
M3 - Conference article
AN - SCOPUS:0035386026
SN - 0018-9464
VL - 37
SP - 2918
EP - 2920
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
IS - 4 I
T2 - 8th Joint Magnetism and Magnetic Materials -International Magnetic Conference- (MMM-Intermag)
Y2 - 7 January 2001 through 11 January 2001
ER -