NeuRow

NeuRow: Online Rowing VR for Motor-Imagery Training

Motor-imagery, or motor-imagination (MI), is a mental rehearsal of a movement and is a unique property of the brain as a mental ability strongly related to the body, or ‘embodied’ cognition [1]. Motor-imagery, appears to share the same control mechanisms and neural substrates with actual movement (both in action execution and action observation), providing a unique opportunity to study neural control of movement in either healthy people or patients [2], [3].

The benefits of motor-imagery are also utilized as a technique in neuro-rehabilitation for people with neurological impairments [4]. More recently, motor-imagery offers an essential basis for the development of Brain–Computer Interfaces (BCIs) for physically disabled persons and stroke survivors [5]. BCIs are communication systems capable of establishing an alternative pathway between user’s brain activity and a computer system [6].

More recently, Virtual Reality (VR) feedback has been used in motor-imagery BCI training, offering a more compelling experience to the user through 3D environments [7]. The fusion of BCI and VR (BCI-VR) allows a wide range of experiences where participants can control various aspects of their environment -either in an explicit or implicit manner-, by using mental imagery alone [8]. This direct brain-to-VR communication can produce induced illusions mostly relying on the sensorimotor contingencies between perception and action [9].

For this, and based on previous findings [10], we have developed a novel prototype that makes use of multimodal feedback, in an immersive VR environment delivered through a state-of-the-art Head Mounted Display (HMD), integrated in a MI-BCI motor training task (left | right hand imagery in a multiplatform setup, NeuRow. NeuRow is Immersive VR Environment for Motor-Imagery training with the use of Brain-Computer Interfaces (BCIs). NeuRow is a rowing game with main target to hit as many flags as possible in a fixed time. Moreover, NeuRow is available for PC, Android OS and also with web browser support through the use of Reh@Panel, a midleware between interfaces and VR. Go To Official NeuRow Website Developed by: Athanasios Vourvopoulos

References:

  • [1] T. Hanakawa, “Organizing motor imageries,” Neurosci. Res.
  • [2] C. Neuper, R. Scherer, S. Wriessnegger, and G. Pfurtscheller, “Motor imagery and action observation: Modulation of sensorimotor brain rhythms during mental control of a brain–computer interface,” Clin. Neurophysiol., vol. 120, no. 2, pp. 239–247, Feb. 2009.
  • [3] T. Mulder, “Motor imagery and action observation: cognitive tools for rehabilitation,” J. Neural Transm., vol. 114, no. 10, pp. 1265–1278, Oct. 2007.
  • [4] R. Dickstein and J. E. Deutsch, “Motor Imagery in Physical Therapist Practice,” Phys. Ther., vol. 87, no. 7, pp. 942–953, Jul. 2007.
  • [5] B. H. Dobkin, “Brain-computer interface technology as a tool to augment plasticity and outcomes for neurological rehabilitation,” J. Physiol., vol. 579, no. Pt 3, pp. 637–642, Mar. 2007.
  • [6] J. R. Wolpaw, N. Birbaumer, D. J. McFarland, G. Pfurtscheller, and T. M. Vaughan, “Brain-computer interfaces for communication and control,” Clin. Neurophysiol. Off. J. Int. Fed. Clin. Neurophysiol., vol. 113, no. 6, pp. 767–791, Jun. 2002.
  • [7] F. Lotte, J. Faller, C. Guger, Y. Renard, G. Pfurtscheller, A. Lécuyer, and R. Leeb, “Combining BCI with Virtual Reality: Towards New Applications and Improved BCI,” 2013.
  • [8] D. Friedman, “Brain-Computer Interfacing and Virtual Reality,” in Handbook of Digital Games and Entertainment Technologies, R. Nakatsu, M. Rauterberg, and P. Ciancarini, Eds. Springer Singapore, 2015, pp. 1–22.
  • [9] M. Slater, “Place illusion and plausibility can lead to realistic behaviour in immersive virtual environments,” Philos. Trans. R. Soc. Lond. B Biol. Sci., vol. 364, no. 1535, pp. 3549–3557, Dec. 2009.
  • [10] A. Vourvopoulos, J. E. M. Cardona, and S. B. i Badia, “Optimizing Motor Imagery Neurofeedback through the Use of Multimodal Immersive Virtual Reality and Motor Priming,” presented at the 2015 International Conference on Virtual Rehabilitation (ICVR), 2015.
For setting up motor-imagery BCI experiments with OpenVibe, a short summary can be found from the OpenVibe tutorial page.
For enhancing the sense of movement in VR, a custom vibrotactile module has been developed with out-of-the-box components including an Arduino board. The vibrotactile module can function as a valuable feedback modality for promoting induced illusions  relying on the sensorimotor contingencies between perception and action, useful in motor-imagery training in BCI. This module is composed by three main components:
  1. Arduino board
  2. Vibrating motors
  3. Cylindrical tubes

1. Arduino board setup:

For connecting the Arduino board with the motors (see figure 1(a)), the following components are needed:
  • 1N4001 Diode
  • 0.1µF ceramic capacitor
  • 1KΩ Resistor
  • 2N2222 NPN Transistor
  • USB Connector

2. Vibrating tubes

– For installing the motors inside the tubes, a 3D printed case has been designed (STL model) in order to accommodate the motor before inserted inside the tube (see figure on the right). – Cylindrical tubes act as grasping objects for simulating the rows movement. For our setup, a pair of carton based tubed had been used with 12cm of length, 3cm diameter and 0.5cm of thickness (see figure 3).

3. Technical specifications

Vibrating Motor Specs:
  • Dimension: 10mm diameter, 2.7mm thick
  • Voltage: 2V – 5V
  • Current Draw:5V current draw: 100mA
    • 4V current draw: 80mA
    • 3V current draw: 60mA
    • 2V current draw: 40mA
  • 11000 RPM at 5V
  • Weight: 0.9 gram
Arduino Mega 2560
  • Microcontroller: ATmega2560
  • Operating Voltage: 5V
  • Input Voltage (recommended): 7-12V
  • Input Voltage (limit): 6-20V
  • Digital I/O Pins: 54 (of which 15 provide PWM output)
  • Analog Input Pins: 16
  • DC Current per I/O Pin: 20 mA
  • DC Current for 3.3V Pin: 50 mA
  • Flash Memory: 256 KB of which 8 KB used by bootloader
  • SRAM: 8 KB
  • EEPROM: 4 KB
  • Clock Speed: 16 MHz
  • Length: 101.52 mm
  • Width: 53.3 mm
  • Weight: 37 g
Finally, upload the following code to the Arduino board for controlling the motors through NeuRow:
String str;
int values[2][6];
int power = 0;
int hand = 0;
int finger = 0;
void setup()
{
Serial.begin(9600);
Serial.flush(); //clears any possible left over information
}
void loop()
{
if(Serial.available() > 0)
{
str = Serial.readStringUntil(';');
power = str.toInt(); str = Serial.readStringUntil(';'); hand = str.toInt(); str = Serial.readStringUntil(';');
finger = str.toInt();
values[hand][finger] = power;
}
for(int i = 0; i <2; i++)
{
for(int j = 0; j < 6; j++)
{
analogWrite(i*6+j+2, values[i][j]);
}
}
}

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