We studied the impact of different visual objects such as a moving hand and a moving cube on the bioelectrical brain activity (i.e., electroencephalogram; EEG). The moving objects were presented in a virtual reality (VR) system via a head mounted display (HMD). Nine healthy volunteers were confronted with 3D visual stimulus presentations in four experimental conditions: (i) static hand, (ii) dynamic hand, (iii) static cube, and (iv) dynamic cube. The results reveal that the processing of moving visual stimuli depends on the type of object: viewing a moving hand results in a stronger desynchronization of the central beta rhythm than viewing a moving cube. This provides further evidence for some extent of motor processing related to visual presentation of objects and implies a greater involvement of motor areas in the brain with the observation of action of different body parts than with the observation of non-body part movements.

Healthy participants are able to move forward within a virtual environment (VE) by the imagination of foot movement. This is achieved by using a brain-computer interface (BCI) that transforms thought-modulated electroencephalogram (EEG) recordings into a control signal. A BCI establishes a communication channel between the human brain and the computer. The basic principle of the Graz-BCI is the detection and classification of motor-imagery-related EEG patterns, whereby the dynamics of sensorimotor rhythms are analyzed. A BCI is a closed-loop system and information is visually fed back to the user about the success or failure of an intended movement imagination. Feedback can be realized in different ways, from a simple moving bar graph to navigation in VEs. The goals of this work are twofold: first, to show the influence of different feedback types on the same task, and second, to demonstrate that it is possible to move through a VE (e.g., a virtual street) without any muscular activity, using only the imagination of foot movement. In the presented work, data from BCI feedback displayed on a conventional monitor are compared with data from BCI feedback in VE experiments with a head-mounted display (HMD) and in a high immersive projection environment (Cave). Results of three participants are reported to demonstrate the proof-of-concept. The data indicate that the type of feedback has an influence on the task performance, but not on the BCI classification accuracy. The participants achieved their best performances viewing feedback in the Cave. Furthermore the VE feedback provided motivation for the subjects.