Detecting gamma frequency neural activity using simultaneous multiband EEG-fMRI

Abstract

Synchronization of gamma frequency (>35Hz) EEG activity is linked to cognitive and sensory behaviour as well as being widely cited as the closest neuronal correlate of the BOLD fMRI signal[1]. However, the majority of gamma-BOLD studies were conducted in the visual[2,3] or auditory[4,5] modalities, therefore a deeper understanding necessitates extension to the motor domain. Simultaneous EEG-fMRI is an ideal method to investigate gamma-BOLD correlates non-invasively in humans, however, residual gradient artefacts typically obscure gamma frequency EEG activity when acquired with fMRI. Accelerated fMRI methods such as multiband (MB)[6,7] allow whole-brain coverage in a sparse fMRI scheme which incorporates MR gradient “quiet periods” thus potentially useful to overcome EEG gradient artefacts during fMRI acquisition