Concurrent electrophysiological and hemodynamic measurements of evoked neural oscillations in human visual cortex using sparsely interleaved fast fMRI and EEG

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2020-08, Vol.217, p.116910-116910, Article 116910
• Main Authors: Lee, Hsin-Ju, Huang, Shu-Yu, Kuo, Wen-Jui, Graham, Simon J., Chu, Ying-Hua, Stenroos, Matti, Lin, Fa-Hsuan
• Format: Article
• Language: English
• Subjects: Blood; Brain Mapping; Brain slice preparation; Echo-Planar Imaging; EEG; Electroencephalography; Electroencephalography - methods; Epilepsy; Evoked Potentials, Visual; Fast MRI; Female; Functional magnetic resonance imaging; Gradient artifact; Hemodynamics; Humans; Image Processing, Computer-Assisted; Inverse imaging; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Multimodal Imaging; Neuroimaging; Oscillations; Phantoms, Imaging; Photic Stimulation; Quality; Spatial distribution; Steady-state visual evoked potential; Visual cortex; Visual Cortex - diagnostic imaging; Visual evoked potentials; Wavelet Analysis; Young Adult
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2020.116910

Electroencephalography (EEG) concurrently collected with functional magnetic resonance imaging (fMRI) is heavily distorted by the repetitive gradient coil switching during the fMRI acquisition. The performance of the typical template-based gradient artifact suppression method can be suboptimal because the artifact changes over time. Gradient artifact residuals also impede the subsequent suppression of ballistocardiography artifacts. Here we propose recording continuous EEG with temporally sparse fast fMRI (fast fMRI-EEG) to minimize the EEG artifacts caused by MRI gradient coil switching without significantly compromising the field-of-view and spatiotemporal resolution of fMRI. Using simultaneous multi-slice inverse imaging to achieve whole-brain fMRI with isotropic 5-mm resolution in 0.1 ​s, and performing these acquisitions once every 2 ​s, we have 95% of the duty cycle available to record EEG with substantially less gradient artifact. We found that the standard deviation of EEG signals over the entire acquisition period in fast fMRI-EEG was reduced to 54% of that in conventional concurrent echo-planar imaging (EPI) and EEG recordings (EPI-EEG) across participants. When measuring 15-Hz steady-state visual evoked potentials (SSVEPs), the baseline-normalized oscillatory neural response in fast fMRI-EEG was 2.5-fold of that in EPI-EEG. The functional MRI responses associated with the SSVEP delineated by EPI and fast fMRI were similar in the spatial distribution, the elicited waveform, and detection power. Sparsely interleaved fast fMRI-EEG provides high-quality EEG without substantially compromising the quality of fMRI in evoked response measurements, and has the potential utility for applications where the onset of the target stimulus cannot be precisely determined, such as epilepsy. •We propose recording continuous EEG with temporally sparse fast fMRI.•Fast MRI can achieve whole-brain sampling with isotropic 5-mm resolution in 0.1 ​s.•Using fast MRI once every 2 ​s substantially reduces the EEG gradient artifact.•The 15-Hz SSVEP in fast fMRI-EEG was 2.5-fold of that in EPI-EEG.•The fMRI responses for 15-Hz SSVEP were similar in EPI and fast fMRI.