PMC6637378_01
Experimental setup, including: (A) the wireless EEG system; (B) the Oculus HMD, together with headphones reproducing the ambient sound from the virtual environment; (C) the vibrotactile modules supported by a custom-made table-tray, similar to the wheelchair trays used for support; (D) the visual feedback with NeuRow game. A written informed consent was obtained for the publication of this image.
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F1
The spatial distribution of the electrodes followed the 10-20 system configuration with the following electrodes over the somatosensory and motor areas: Frontal-Central (FC5, FC6), Central (C1, C2, C3, C4), and Central-Parietal (CP5, CP6) (Figure 1A). The HMD is made of one 7'' 1280 x 800 60 Hz LCD display (640 x 800 resolution per eye), one aspheric acrylic lens per eye, 110o Field of View (FOV), internal tracking through a gyroscope, accelerometer, and magnetometer, with a tracking frequency of 1000 Hz (Figure 1B). In our setup, a pair of tubes with 12 cm (4.7 inches) of length and 3 cm (1.2 inches) diameter were used (Figure 1C). This serves as an additional safety feature to ensure that the user does not deviate from the target since the virtual environment is procedurally generated (Figure 1D).
BCI Protocol: (A) Intervention stages including the setup, training, resting period and finally the BCI task. (B) The training stages. (C) Training feedback distributed in 24 epochs per class (left|right)
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F2
The training session was configured to acquire data in 24 blocks (epochs) per class (left or right hand imagery) in a randomized order (Figure 2).
fMRI protocol. (a) Motor-Execution feedback, (b) Motor-Imagery feedback with directional arrows, (c) Motor-Observation feedback of NeuRow.
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F3
In the finger-tapping execution condition (ME), the patient was instructed to execute a sequential finger-tapping task (index-middle-ring-little-index-middle-ring-little) from a first-person perspective with his non-affected arm (Figure 3a). In the finger-tapping motor imagery condition (MI), the patient had to imagine the kinesthetic experience of the previous finger-tapping task for the left and right hand separately, based on the provided stimulus/instruction (Figure 3b). Imagery protocol. In the last condition, the motor observation (MO), patient had to observe and imagine the kinesthetic experience of the rowing task from NeuRow from the first-person perspective for the left and right hand separately, based on the provided stimulus (Figure 3c).