Estimation of brain response to multimodal stimuli by index of spatiotemporal locality by magnetoencephalography

Abstract

Brain‐computer interface (BCI) enables people who cannot move their own body freely to manipulate machines and helps their communication and life. Recent brain‐computer interface (BCI) uses multimodal stimuli to increase bit rate of the system, so it is important to reveal when and which part of the brain part is activated to discriminate target stimuli. Although magnetoencephalography (MEG) measures brain activity with high spatial and temporal resolution, there are a few indexes to estimate spatiotemporal locality of response. We propose an index to estimate spatiotemporal locality of response to multimodal stimuli of an oddball paradigm from magnetoencephalography (MEG) signals. The validity of proposed index is demonstrated by simulation. Discrimination task was conducted with different ratio of target/nontarget stimuli with visual and auditory location. Response to visual target stimuli was strong and made no spatiotemporal difference, so visual dominance was implied.