Objective: While noninvasive electroencephalography (EEG) based brain-computer interfacing (BCI) has been successfully demonstrated in two-dimensional (2D) control tasks, little work has been published regarding its extension to practical three-dimensional (3D) control. Methods: In this study, we developed a new BCI approach for 3D control by combining a novel form of endogenous visuospatial attentional modulation, defined as overt spatial attention (OSA), and motor imagery (MI). Results: OSA modulation was shown to provide comparable control to conventional MI modulation in both oneand two- dimensional tasks. Furthermore, this work provides evidence for the functional independence of traditional MI and OSA, as well as an investigation into the simultaneous use of both. Using this newly proposed BCI paradigm, sixteen participants successfully completed a 3D eight target control task. Nine of these subjects further demonstrated robust 3D control in a twelve target task, significantly outperforming the information transfer rate achieved in the 1D and 2D control task (29.7±1.6 bits/min). Conclusion: These results strongly support the hypothesis that noninvasive EEG based BCI can provide robust 3D control through endogenous neural modulation in broader populations with limited training.

Motor imagery-based (MI based) brain-computer interface (BCI) using electroencephalography (EEG) allows users to directly control a computer or external device by modulating and decoding the brain waves. A variety of factors could potentially affect the performance of BCI such as the health status of subjects or the environment. In this study, we investigated the effects of soft drinks and regular coffee on EEG signals under resting state and on the performance of MI based BCI. Twenty-six healthy human subjects participated in three or four BCI sessions with a resting period in each session. During each session, the subjects drank an unlabeled soft drink with either sugar (Caffeine Free Coca-Cola), caffeine (Diet Coke), neither ingredient (Caffeine Free Diet Coke), or a regular coffee if there was a fourth session. The resting state spectral power in each condition was compared; the analysis showed that power in alpha and beta band after caffeine consumption were decreased substantially compared to control and sugar condition. Although the attenuation of powers in the frequency range used for the online BCI control signal was shown, group averaged BCI online performance after consuming caffeine was similar to those of other conditions. This work, for the first time, shows the effect of caffeine, sugar intake on the online BCI performance and resting state brain signal.