Surface EMG measurements during fMRI at 3T: accurate EMG recordings after artifact correction.
In this experiment, we have measured surface EMG of the first dorsal interosseus during predefined submaximal isometric contractions (5, 15, 30, 50, and 70% of maximal force) of the index finger simultaneously with fMRI measurements. Since we have used sparse sampling fMRI (3-s scanning; 2-s non-scanning), we were able to compare the mean amplitude of the undisturbed EMG (non-scanning) intervals with the mean amplitude of the EMG intervals during scanning, after MRI artifact correction. The agreement between the mean amplitudes of the corrected and the undisturbed EMG was excellent and the mean difference between the two amplitudes was not significantly different. Furthermore, there was no significant difference between the corrected and undisturbed amplitude at different force levels. In conclusion, we have shown that it is feasible to record surface EMG during scanning and that, after MRI artifact correction, the EMG recordings can be used to quantify isometric muscle activity, even at very low activation intensities.
van Duinen
Hiske
H
BCN-NeuroImaging Center, University of Groningen Medical Center, Groningen, The Netherlands. h.van.duinen@med.umcg.nl
Zijdewind
Inge
I
Hoogduin
Hans
H
Maurits
Natasha
N
D016477:Artifacts; D004576:Electromyography / Q000379:methods*; D005385:Fingers / Q000294:innervation / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007537:Isometric Contraction / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology