Mental imagery-based brain-computer interface (BCI)-protocols mostly allow users to focus on the ... more Mental imagery-based brain-computer interface (BCI)-protocols mostly allow users to focus on the task without external interferences. Environmental stimuli, however, may hamper users' ability to generate proper brain activity patterns. The aim of this study was to investigate whether users are able to retain satisfactory BCI control during auditory distraction, and whether distinct mental tasks are affected differently from auditory distraction. Twelve participants controlled a 4-class BCI with the mental tasks word association, mental subtraction, spatial navigation and motor imagery by modulation of EEG frequency bands in 10 sessions. Simultaneously to the imagery task, users had to either ignore all tones (passive distraction) that were presented according to an oddball paradigm or react upon the target tone (active distraction). Passive distraction led to an increased user performance compared to active distraction and no distraction condition. Differences between motor imagery and the other three mental tasks in performance were reflected in the P300 amplitude, latency and reaction time and thus might indicate differences in workload. Auditory distraction had no adverse effect on the BCI performance of the examined mental task. Our results are encouraging for real-world application as participants succeeded in operating the 4-class BCI during auditory distraction.
The present study is the first that examined neuronal underpinnings of spatial presence using mul... more The present study is the first that examined neuronal underpinnings of spatial presence using multi-channel EEG in an interactive virtual reality (VR). We compared two VR-systems: a highly immersive Single-Wall-VR-system (three-dimensional view, large screen) and a less immersive Desktop-VR-system (two-dimensional view, small screen). Twenty-nine participants performed a spatial navigation task in a virtual maze and had to state their sensation of "being there" on a 5-point rating scale. Task-related power decrease/increase (TRPD/TRPI) in the Alpha band (8-12Hz) and coherence analyses in different frequency bands were used to analyze the EEG data. The Single-Wall-VR-system caused a more intense presence experience than the Desktop-VR-system. This increased feeling of presence in the Single-Wall-VR-condition was accompanied by an increased parietal TRPD in the Alpha band, which is associated with cortical activation. The lower presence experience in the Desktop-VR-group was accompanied by a stronger functional connectivity between frontal and parietal brain regions indicating that the communication between these two brain areas is crucial for the presence experience. Hence, we found a positive relationship between presence and parietal brain activation and a negative relationship between presence and frontal brain activation in an interactive VR-paradigm, supporting the results of passive non-interactive VR-studies.
Mental imagery-based brain-computer interface (BCI)-protocols mostly allow users to focus on the ... more Mental imagery-based brain-computer interface (BCI)-protocols mostly allow users to focus on the task without external interferences. Environmental stimuli, however, may hamper users' ability to generate proper brain activity patterns. The aim of this study was to investigate whether users are able to retain satisfactory BCI control during auditory distraction, and whether distinct mental tasks are affected differently from auditory distraction. Twelve participants controlled a 4-class BCI with the mental tasks word association, mental subtraction, spatial navigation and motor imagery by modulation of EEG frequency bands in 10 sessions. Simultaneously to the imagery task, users had to either ignore all tones (passive distraction) that were presented according to an oddball paradigm or react upon the target tone (active distraction). Passive distraction led to an increased user performance compared to active distraction and no distraction condition. Differences between motor imagery and the other three mental tasks in performance were reflected in the P300 amplitude, latency and reaction time and thus might indicate differences in workload. Auditory distraction had no adverse effect on the BCI performance of the examined mental task. Our results are encouraging for real-world application as participants succeeded in operating the 4-class BCI during auditory distraction.
The present study is the first that examined neuronal underpinnings of spatial presence using mul... more The present study is the first that examined neuronal underpinnings of spatial presence using multi-channel EEG in an interactive virtual reality (VR). We compared two VR-systems: a highly immersive Single-Wall-VR-system (three-dimensional view, large screen) and a less immersive Desktop-VR-system (two-dimensional view, small screen). Twenty-nine participants performed a spatial navigation task in a virtual maze and had to state their sensation of "being there" on a 5-point rating scale. Task-related power decrease/increase (TRPD/TRPI) in the Alpha band (8-12Hz) and coherence analyses in different frequency bands were used to analyze the EEG data. The Single-Wall-VR-system caused a more intense presence experience than the Desktop-VR-system. This increased feeling of presence in the Single-Wall-VR-condition was accompanied by an increased parietal TRPD in the Alpha band, which is associated with cortical activation. The lower presence experience in the Desktop-VR-group was accompanied by a stronger functional connectivity between frontal and parietal brain regions indicating that the communication between these two brain areas is crucial for the presence experience. Hence, we found a positive relationship between presence and parietal brain activation and a negative relationship between presence and frontal brain activation in an interactive VR-paradigm, supporting the results of passive non-interactive VR-studies.
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Papers by Christa Neuper