Cortical Source Localization for Analysing Single-Trial Motor Imagery EEG

Electroencephalography (EEG) is the most widely used Brain-Computer Interface (BCI) modality to record brain signal. Unlike other neuroimaging modalities like fMRI and PET, EEG is not very effective in localizing the brain sources. However, with the advent of inverse modeling techniques for source localization, it is possible to use EEG as an alternative neuroimaging technique. In this paper, source localization using EEG signal is used to analyze single-trial movement imagination (MI) tasks. Wadsworth physiobank dataset of 109 subjects performing right hand vs left hand movement imagination is considered. Forward modeling based on 3 layered head geometry is co-registered with ICBM 152 template anatomy, which is a non-linear average of fMRI scans of 152 subjects. Inverse modeling is done with the help of Standardized Low Resolution Electromagnetic Tomography (sLORETA). The proposed method presents some preliminary results on how source localization could be used to identify the moment (time instant) of brain source activation even within a single trial.