Mar 02, 2014

3D Thought controlled environment via Interaxon

In this demo video, artist Alex McLeod shows an environment he designed for Interaxon to use at CES in 2011 interaxon.ca/CES#.

The glasses display the scene in 3D and attaches sensors read users brain-states which control elements of the scene.

3D Thought controlled environment via Interaxon from Alex McLeod on Vimeo.

Dec 21, 2013

New Scientist: Mind-reading light helps you stay in the zone

Re-blogged from New Scientist

WITH a click of a mouse, I set a path through the mountains for drone #4. It's one of five fliers under my control, all now heading to different destinations. Routes set, their automation takes over and my mind eases, bringing a moment of calm. But the machine watching my brain notices the lull, decides I can handle more, and drops a new drone in the south-east corner of the map.

The software is keeping my brain in a state of full focus known as flow, or being "in the zone". Too little work, and the program notices my attention start to flag and gives me more drones to handle. If I start to become a frazzled air traffic controller, the computer takes one of the drones off my plate, usually without me even noticing.

The system monitors the workload by pulsing light into my prefrontal cortex 12 times a second. The amount of light that oxygenated and deoxygenated haemoglobin in the blood there absorbs and reflects gives an indication of how mentally engaged I am. Harder brain work calls for more oxygenated blood, and changes how the light is absorbed. Software interprets the signal from this functional near infrared spectroscopy (fNIRS) and uses it to assign me the right level of work.

Dan Afergan, who is running the study at Tufts University in Medford, Massachusetts, points to an on-screen readout as I play. "It's predicting high workload with very high certainty, and, yup, number three just dropped off," he says over my shoulder. Sure enough, I'm now controlling just five drones again.

To achieve this mind-monitoring, I'm hooked up to a bulky rig of fibre-optic cables and have an array of LEDs stuck to my forehead. The cables stream off my head into a box that converts light signals to electrical ones. These fNIRS systems don't have to be this big, though. A team led by Sophie Piper at Charité University of Medicine in Berlin, Germany, tested a portable device on cyclists in Berlin earlier this year – the first time fNIRS has been done during an outdoor activity.

Afergan doesn't plan to be confined to the lab for long either. He's studying ways to integrate brain-activity measuring into the Google Glass wearable computer. A lab down the hall already has a prototype fNIRS system on a chip that could, with a few improvements, be built into a Glass headset. "Glass is already on your forehead. It's really not much of a stretch to imagine building fNIRS into the headband," he says.

Afergan is working on a Glass navigation system for use in cars that responds to a driver's level of focus. When they are concentrating hard, Glass will show only basic instructions, or perhaps just give audio directions. When the driver is focusing less, on a straight stretch of road perhaps, Glass will provide more details of the route. The team also plans to adapt Google Now – the company's digital assistant software – for Glass so that it only gives you notifications when your mind has room for them.

Peering into drivers' minds will become increasingly important, says Erin Solovey, a computer scientist at Drexel University in Philadelphia, Pennsylvania. Many cars have automatic systems for adaptive cruise control, keeping in the right lane and parking. These can help, but they also bring the risk that drivers may not stay focused on the task at hand, because they are relying on the automation.

Systems using fNIRS could monitor a driver's focus and adjust the level of automation to keep drivers safely engaged with what the car is doing, she says.

This article appeared in print under the headline "Stay in the zone"

Nov 28, 2013

Effect of mindfulness meditation on brain-computer interface performance

Effect of mindfulness meditation on brain-computer interface performance.

Conscious Cogn. 2013 Nov 22;23C:12-21

Authors: Tan LF, Dienes Z, Jansari A, Goh SY

Abstract. Electroencephalogram based Brain-Computer Interfaces (BCIs) enable stroke and motor neuron disease patients to communicate and control devices. Mindfulness meditation has been claimed to enhance metacognitive regulation. The current study explores whether mindfulness meditation training can thus improve the performance of BCI users. To eliminate the possibility of expectation of improvement influencing the results, we introduced a music training condition. A norming study found that both meditation and music interventions elicited clear expectations for improvement on the BCI task, with the strength of expectation being closely matched. In the main 12week intervention study, seventy-six healthy volunteers were randomly assigned to three groups: a meditation training group; a music training group; and a no treatment control group. The mindfulness meditation training group obtained a significantly higher BCI accuracy compared to both the music training and no-treatment control groups after the intervention, indicating effects of meditation above and beyond expectancy effects.

Oct 31, 2013

Mobile EEG and its potential to promote the theory and application of imagery-based motor rehabilitation

Mobile EEG and its potential to promote the theory and application of imagery-based motor rehabilitation.

Int J Psychophysiol. 2013 Oct 18;

Authors: Kranczioch C, Zich C, Schierholz I, Sterr A

Abstract. Studying the brain in its natural state remains a major challenge for neuroscience. Solving this challenge would not only enable the refinement of cognitive theory, but also provide a better understanding of cognitive function in the type of complex and unpredictable situations that constitute daily life, and which are often disturbed in clinical populations. With mobile EEG, researchers now have access to a tool that can help address these issues. In this paper we present an overview of technical advancements in mobile EEG systems and associated analysis tools, and explore the benefits of this new technology. Using the example of motor imagery (MI) we will examine the translational potential of MI-based neurofeedback training for neurological rehabilitation and applied research.

Aug 07, 2013

German test of the controllability of motor imagery in older adults

German test of the controllability of motor imagery in older adults.

Z Gerontol Geriatr. 2013 Aug 3;

Authors: Schott N

Abstract. After a person is instructed to imagine a certain movement, no possibility exists to control whether the person is doing what they are asked for. The purpose of this study was to validate the German Test of the Controllability of Motor Imagery ("Tests zur Kontrollierbarkeit von Bewegungsvorstellungen" TKBV). A total sample of 102 men [mean 55.6, standard deviation (SD) 25.1] and 93 women (mean 59.2, SD 24.0) ranging in age from 18-88 years completed the TKBV. Two conditions were performed: a recognition (REC) and a regeneration (REG) test. In both conditions the participants had to perform the six consecutive instructions. They were asked to imagine the posture of their own body. Subjects had to move only one body part (head, arms, legs, trunk) per instruction. On the regeneration test the participants had to actually produce the final position. On the recognition test, they were required to select the one picture among five pictures, which fit the imagery they have. Explorative factor analysis showed the proposed two-dimensional solution: (1) the ability to control their body scheme, and (2) the ability to transform a visual imagery. Cronbach's α of the two dimensions of the TKBV were 0.89 and 0.73, respectively. The scales correlate low with convergent measures assessing mental chronometry (Timed-Up-and-Go test, rREG = - 0.33, rREC = - 0.31), and the vividness of motor imagery (MIQvis, rREG = 0.14, rREC = 0.14; MIQkin, rREG = 0.11, rREC = 0.13). Criterion validity of the TKBV was established by statistically significant correlations between the subscales, the Corsi block tapping test (BTT, rREG = 0.45, rREC = 0.38) and with physical activity (rREG = 0.50, rREC = 0.36). The TKBV is a valid instrument to assess motor imagery. Thus, it is an important and helpful tool in the neurologic and orthopedic rehabilitation.

May 07, 2012

Social influences on neuroplasticity: stress and interventions to promote well-being

Social influences on neuroplasticity: stress and interventions to promote well-being.

Nat Neurosci. 2012;15(5):689-95

Authors: Davidson RJ, McEwen BS

Experiential factors shape the neural circuits underlying social and emotional behavior from the prenatal period to the end of life. These factors include both incidental influences, such as early adversity, and intentional influences that can be produced in humans through specific interventions designed to promote prosocial behavior and well-being. Here we review important extant evidence in animal models and humans. Although the precise mechanisms of plasticity are still not fully understood, moderate to severe stress appears to increase the growth of several sectors of the amygdala, whereas the effects in the hippocampus and prefrontal cortex tend to be opposite. Structural and functional changes in the brain have been observed with cognitive therapy and certain forms of meditation and lead to the suggestion that well-being and other prosocial characteristics might be enhanced through training.

Apr 20, 2012

Enhancement of motor imagery-related cortical activation during first-person observation measured by functional near-infrared spectroscopy

Enhancement of motor imagery-related cortical activation during first-person observation measured by functional near-infrared spectroscopy. 

Eur J Neurosci. 2012 Apr 18;

Authors: Kobashi N, Holper L, Scholkmann F, Kiper D, Eng K 

Abstract. It is known that activity in secondary motor areas during observation of human limbs performing actions is affected by the observer's viewpoint, with first-person views generally leading to stronger activation. However, previous neuroimaging studies have displayed limbs in front of the observer, providing an offset view of the limbs without a truly first-person viewpoint. It is unknown to what extent these pseudo-first-person viewpoints have affected the results published to date. In this experiment, we used a horizontal two-dimensional mirrored display that places virtual limbs at the correct egocentric position relative to the observer. We compared subjects using the mirrored and conventional displays while recording over the premotor cortex with functional near-infrared spectroscopy. Subjects watched a first-person view of virtual arms grasping incoming balls on-screen; they were instructed to either imagine the virtual arm as their own [motor imagery during observation (MIO)] or to execute the movements [motor execution (ME)]. With repeated-measures anova, the hemoglobin difference as a direct index of cortical oxygenation revealed significant main effects of the factors hemisphere (P = 0.005) and condition (P ≤ 0.001) with significant post hoc differences between MIO-mirror and MIO-conventional (P = 0.024). These results suggest that the horizontal mirrored display provides a more accurate first-person view, enhancing subjects' ability to perform motor imagery during observation. Our results may have implications for future experimental designs involving motor imagery, and may also have applications in video gaming and virtual reality therapy, such as for patients following stroke.

Neurofeedback using real-time near-infrared spectroscopy enhances motor imagery related cortical activation

Neurofeedback using real-time near-infrared spectroscopy enhances motor imagery related cortical activation. 

PLoS One. 2012;7(3):e32234 

Authors: Mihara M, Miyai I, Hattori N, Hatakenaka M, Yagura H, Kawano T, Okibayashi M, Danjo N, Ishikawa A, Inoue Y, Kubota K 

Abstract. Accumulating evidence indicates that motor imagery and motor execution share common neural networks. Accordingly, mental practices in the form of motor imagery have been implemented in rehabilitation regimes of stroke patients with favorable results. Because direct monitoring of motor imagery is difficult, feedback of cortical activities related to motor imagery (neurofeedback) could help to enhance efficacy of mental practice with motor imagery. To determine the feasibility and efficacy of a real-time neurofeedback system mediated by near-infrared spectroscopy (NIRS), two separate experiments were performed. Experiment 1 was used in five subjects to evaluate whether real-time cortical oxygenated hemoglobin signal feedback during a motor execution task correlated with reference hemoglobin signals computed off-line. Results demonstrated that the NIRS-mediated neurofeedback system reliably detected oxygenated hemoglobin signal changes in real-time. In Experiment 2, 21 subjects performed motor imagery of finger movements with feedback from relevant cortical signals and irrelevant sham signals. Real neurofeedback induced significantly greater activation of the contralateral premotor cortex and greater self-assessment scores for kinesthetic motor imagery compared with sham feedback. These findings suggested the feasibility and potential effectiveness of a NIRS-mediated real-time neurofeedback system on performance of kinesthetic motor imagery. However, these results warrant further clinical trials to determine whether this system could enhance the effects of mental practice in stroke patients.

Jan 27, 2012

Cued motor imagery in patients with multiple sclerosis

Cued motor imagery in patients with multiple sclerosis.

Neuroscience. 2012 Jan 8

Authors: Heremans E, Nieuwboer A, Spildooren J, Bondt SD, D'hooge AM, Helsen W, Feys P

Abstract. Motor imagery (MI) is a promising practice tool in neurorehabilitation. However, in patients with multiple sclerosis (MS), impairments in MI accuracy and temporal organization were found during clinical assessment, which may limit the benefits of MI practice. Therefore, we investigated whether the MI quality of MS patients could be optimized by means of external cueing. Fourteen patients with MS and 14 healthy control patients physically executed and visually imagined a goal-directed upper limb task in the presence and absence of added visual and auditory cues. MI quality was assessed by means of eye-movement registration. As main results, it was found that MS patients had significant higher eye-movement times than controls during both execution and imagery, and overestimated the to-be-imagined movement amplitude when no external information was provided during imagery. External cues, however, decreased patients' MI duration and increased the spatial accuracy of their imagined movements. In sum, our results indicate that MS patients imagine movements in a better way when they are provided with external cues during MI. These findings are important for developing rehabilitation strategies based on MI in patients with MS.

A combined robotic and cognitive training for locomotor rehabilitation

A combined robotic and cognitive training for locomotor rehabilitation: evidences of cerebral functional reorganization in two chronic traumatic brain injured patients.

Front Hum Neurosci. 2011;5:146

Authors: Sacco K, Cauda F, D'Agata F, Duca S, Zettin M, Virgilio R, Nascimbeni A, Belforte G, Eula G, Gastaldi L, Appendino S, Geminiani G

Abstract. It has been demonstrated that automated locomotor training can improve walking capabilities in spinal cord-injured subjects but its effectiveness on brain damaged patients has not been well established. A possible explanation of the discordant results on the efficacy of robotic training in patients with cerebral lesions could be that these patients, besides stimulation of physiological motor patterns through passive leg movements, also need to train the cognitive aspects of motor control. Indeed, another way to stimulate cerebral motor areas in paretic patients is to use the cognitive function of motor imagery. A promising possibility is thus to combine sensorimotor training with the use of motor imagery. The aim of this paper is to assess changes in brain activations after a combined sensorimotor and cognitive training for gait rehabilitation. The protocol consisted of the integrated use of a robotic gait orthosis prototype with locomotor imagery tasks. Assessment was conducted on two patients with chronic traumatic brain injury and major gait impairments, using functional magnetic resonance imaging. Physiatric functional scales were used to assess clinical outcomes. Results showed greater activation post-training in the sensorimotor and supplementary motor cortices, as well as enhanced functional connectivity within the motor network. Improvements in balance and, to a lesser extent, in gait outcomes were also found.

Dec 31, 2011

Motor performance may be improved by kinesthetic imagery, specific action verb production, and mental calculation

Motor performance may be improved by kinesthetic imagery, specific action verb production, and mental calculation.

Neuroreport. 2011 Nov 25;

Authors: Rabahi T, Fargier P, Rifai-Sarraj A, Clouzeau C, Massarelli R

Abstract. Several results in the literature show that motor imagery, language production, mental calculation, and motor execution share the same or closely related brain motor cortical areas. The present study aimed at investigating the possible influence of specific action verb (AV) pronunciation and mental calculus upon motor performance compared with kinesthetic imagery (KI). Participants, novice in mental imagery, performed a vertical jump after a cognitive task (AV, silent AV, mental subtraction, meaningless verb, and KI). The results show that specific lower limbs AV, mental calculation, and KI improved the vertical jump in male, but not in female participants.

Improving spatial abilities through mindfulness: effects on the mental rotation task

Improving spatial abilities through mindfulness: effects on the mental rotation task.

Conscious Cogn. 2011 Sep;20(3):801-6

Authors: Geng L, Zhang L, Zhang D

Abstract. In this study, we demonstrate a previously unknown finding that mindful learning can improve an individual's spatial cognition without regard to gender differences. Thirty-two volunteers participated in the experiment. Baselines for spatial ability were first measured for the reaction time on the mental rotation task. Next, the participants were randomly assigned to either a mindful or mindless learning condition. After learning, the mental rotation task showed that those in the mindful learning condition responded faster than those in the mindless learning condition. This study provides promising evidence for applying mindful learning to education.

Nov 06, 2011

Role of the Primary Motor Cortex in the Early Boost in Performance Following Mental Imagery Training

Role of the Primary Motor Cortex in the Early Boost in Performance Following Mental Imagery Training

 

PLoS One. 2011;6(10):e26717

 

Authors: Debarnot U, Clerget E, Olivier E

Abstract. Recently, it has been suggested that the primary motor cortex (M1) plays a critical role in implementing the fast and transient post-training phase of motor skill consolidation, known to yield an early boost in performance. Whether a comparable early boost in performance occurs following motor imagery (MIM) training is still unknown. To address this issue, two groups of subjects learned a finger tapping sequence either by MIM or physical practice (PP). In both groups, performance increased significantly in the post-training phase when compared with the pre-training phase and further increased after a 30 min resting period, indicating that both MIM and PP trainings were equally efficient and induced an early boost in motor performance. This conclusion was corroborated by the results of an additional control group. In a second experiment, we then investigated the causal role of M1 in implementing the early boost process resulting from MIM training. To do so, we inhibited M1 by applying a continuous theta-burst stimulation (cTBS) in healthy volunteers just after they learnt, by MIM, the same finger-tapping task as in Experiment #1. As a control, cTBS was applied over the vertex of subjects who underwent the same experiment. We found that cTBS applied over M1 selectively abolished the early boost process subsequent to MIM training. Altogether, the present study provides evidence that MIM practice induces an early boost in performance and demonstrates that M1 is causally involved in this process. These findings further divulge some degree of behavioral and neuronal similitude between MIM and PP.

Aug 17, 2010

Using mirror visual feedback and virtual reality to treat fibromyalgia

Using mirror visual feedback and virtual reality to treat fibromyalgia.

Med Hypotheses. 2010 Aug 5;

Authors: Ramachandran VS, Seckel EL

Fibromyalgia is a condition characterized by long term body-wide pain and tender points in joints, muscles and soft tissues. Other symptoms include chronic fatigue, morning stiffness, and depression. It is well known that these symptoms are exacerbated under periods of high stress. When pain becomes severe enough, the mind can enter what is known as a dissociative state, characterized by depersonalization - the feeling of detachment from one's physical body and the illusion of watching one's physical body from outside. In evolutionary terms, dissociative states are thought to be an adaptive mechanism to mentally distance oneself from pain, often during trauma. Similar dissociative experiences are reported by subjects who have used psychoactive drugs such as ketamine. We have previously used non-invasive mirror visual feedback to treat subjects with chronic pain from phantom limbs and suggested its use for complex regional pain syndrome: once considered intractable pain. We wondered whether such methods would work to alleviate the chronic pain of fibromyalgia. We tested mirror visual feedback on one fibromyalgia patient. On 15 trials, the patient's lower limb pain rating (on a scale from 1 to 10) decreased significantly. These preliminary results suggest that non-invasive dissociative anesthetics such as VR goggles, ketamine, and mirror visual feedback could be used to alleviate chronic pain from fibromyalgia. This would furnish us with a better understanding of the mechanism by which external visual feedback interacts with the internal physical manifestation of pain.

Jan 07, 2010

Sleep contribution to motor memory consolidation: a motor imagery study

Sleep contribution to motor memory consolidation: a motor imagery study.

Sleep. 2009 Dec 1;32(12):1559-65

Authors: Debarnot U, Creveaux T, Collet C, Doyon J, Guillot A

STUDY OBJECTIVES: Sleep is known to enhance performance following physical practice (PP) of a new sequence of movements. Apart from a pilot study, it is still unknown whether a similar sleep-dependent consolidation effect can be observed following motor imagery (MI) and whether this mnemonic process is related to MI speed. DESIGN: Counterbalanced within-subject design. SETTING: The laboratory. PARTICIPANTS: Thirty-two participants. INTERVENTIONS: PP, real-time MI, fast MI, and NoSleep (control) groups. MEASUREMENTS AND RESULTS: Subjects practiced an explicitly known sequence of finger movements, and were assigned to PP, real-time MI, or fast MI, in which they intentionally imagined the sequence at a faster pace. A NoSleep group subjected to real-time MI, but without any intervening sleep, was also tested. Performance was evaluated before practice, as well as prior to, and after a night of sleep or a similar time interval during the daytime. Compared with the NoSleep group, the results revealed offline gains in performance after sleep in the PP, real-time MI, and fast MI groups. There was no correlation between a measure of underestimation of the time to imagine the motor sequence and the actual speed gains after sleep, neither between the ease/difficulty to form mental images and performance gains. CONCLUSIONS: These results provide evidence that sleep contributes to the consolidation of motor sequence learning acquired through MI and further suggests that offline delayed gains are not related to the MI content per se. They extend our previous findings and strongly confirm that performance enhancement following MI is sleep dependent.

Oct 20, 2009

Inducing a virtual hand ownership illusion through a brain-computer interface

Inducing a virtual hand ownership illusion through a brain-computer interface.

Neuroreport. 2009 Apr 22;20(6):589-594

Authors: Perez-Marcos D, Slater M, Sanchez-Vives MV

The apparently stable brain representation of our bodies is easily challenged. We have recently shown that the illusion of ownership of a three-dimensional virtual hand can be evoked through synchronous tactile stimulation of a person's hidden real hand and that of the virtual hand. This reproduces the well-known rubber-hand illusion, but in virtual reality. Here we show that some aspects of the illusion can also occur through motor imagery used to control movements of a virtual hand. When movements of the virtual hand followed motor imagery, the illusion of ownership of the virtual hand was evoked and muscle activity measured through electromyogram correlated with movements of the virtual arm. Using virtual bodies has a great potential in the fields of physical and neural rehabilitation, making the understanding of ownership of a virtual body highly relevant.

Sep 21, 2009

Driving dreams: cortical activations during imagined passive and active whole body movemen

Driving dreams: cortical activations during imagined passive and active whole body movement.

Ann N Y Acad Sci. 2009 May;1164:372-5

Authors: Flanagin VL, Wutte M, Glasauer S, Jahn K

It is unclear how subjects perceive and process self-motion cues in virtual reality environments. Movement could be perceived as passive, akin to riding in a car, or active, such as walking down the street. These two very different types of self-motion were studied here using motor imagery in fMRI. In addition, the relative importance of visual and proprioceptive training cues was examined. Stronger activations were found during proprioceptive motor imagery compared with visual motor imagery, suggesting that proprioceptive signals are important for successful imagined movement. No significant activations were found during active movement with proprioceptive training. Passive locomotion, however, was correlated with activity in an occipital-parietal and parahippocampal cortical network, which are the same regions found during navigation with virtual reality stimuli.

Neurofeedback-based motor imagery training for brain-computer interface

Neurofeedback-based motor imagery training for brain-computer interface (BCI).

J Neurosci Methods. 2009 Apr 30;179(1):150-6

Authors: Hwang HJ, Kwon K, Im CH

In the present study, we propose a neurofeedback-based motor imagery training system for EEG-based brain-computer interface (BCI). The proposed system can help individuals get the feel of motor imagery by presenting them with real-time brain activation maps on their cortex. Ten healthy participants took part in our experiment, half of whom were trained by the suggested training system and the others did not use any training. All participants in the trained group succeeded in performing motor imagery after a series of trials to activate their motor cortex without any physical movements of their limbs. To confirm the effect of the suggested system, we recorded EEG signals for the trained group around sensorimotor cortex while they were imagining either left or right hand movements according to our experimental design, before and after the motor imagery training. For the control group, we also recorded EEG signals twice without any training sessions. The participants' intentions were then classified using a time-frequency analysis technique, and the results of the trained group showed significant differences in the sensorimotor rhythms between the signals recorded before and after training. Classification accuracy was also enhanced considerably in all participants after motor imagery training, compared to the accuracy before training. On the other hand, the analysis results for the control EEG data set did not show consistent increment in both the number of meaningful time-frequency combinations and the classification accuracy, demonstrating that the suggested system can be used as a tool for training motor imagery tasks in BCI applications. Further, we expect that the motor imagery training system will be useful not only for BCI applications, but for functional brain mapping studies that utilize motor imagery tasks as well.

Jul 01, 2009

A virtual reality-based system integrated with fmri to study neural mechanisms of action observation-execution

A virtual reality-based system integrated with fmri to study neural mechanisms of action observation-execution: A proof of concept study.

Restor Neurol Neurosci. 2009;27(3):209-23

Authors: Adamovich SV, August K, Merians A, Tunik E

Purpose: Emerging evidence shows that interactive virtual environments (VEs) may be a promising tool for studying sensorimotor processes and for rehabilitation. However, the potential of VEs to recruit action observation-execution neural networks is largely unknown. For the first time, a functional MRI-compatible virtual reality system (VR) has been developed to provide a window into studying brain-behavior interactions. This system is capable of measuring the complex span of hand-finger movements and simultaneously streaming this kinematic data to control the motion of representations of human hands in virtual reality. Methods: In a blocked fMRI design, thirteen healthy subjects observed, with the intent to imitate (OTI), finger sequences performed by the virtual hand avatar seen in 1st person perspective and animated by pre-recorded kinematic data. Following this, subjects imitated the observed sequence while viewing the virtual hand avatar animated by their own movement in real-time. These blocks were interleaved with rest periods during which subjects viewed static virtual hand avatars and control trials in which the avatars were replaced with moving non-anthropomorphic objects. Results: We show three main findings. First, both observation with intent to imitate and imitation with real-time virtual avatar feedback, were associated with activation in a distributed frontoparietal network typically recruited for observation and execution of real-world actions. Second, we noted a time-variant increase in activation in the left insular cortex for observation with intent to imitate actions performed by the virtual avatar. Third, imitation with virtual avatar feedback (relative to the control condition) was associated with a localized recruitment of the angular gyrus, precuneus, and extrastriate body area, regions which are (along with insular cortex) associated with the sense of agency. Conclusions: Our data suggest that the virtual hand avatars may have served as disembodied training tools in the observation condition and as embodied "extensions" of the subject's own body (pseudo-tools) in the imitation. These data advance our understanding of the brain-behavior interactions when performing actions in VE and have implications in the development of observation- and imitation-based VR rehabilitation paradigms.

Jun 24, 2009

Neurofeedback-based motor imagery training for brain-computer interface

Neurofeedback-based motor imagery training for brain-computer interface (BCI).

J Neurosci Methods. 2009 Apr 30;179(1):150-6

Authors: Hwang HJ, Kwon K, Im CH

In the present study, we propose a neurofeedback-based motor imagery training system for EEG-based brain-computer interface (BCI). The proposed system can help individuals get the feel of motor imagery by presenting them with real-time brain activation maps on their cortex. Ten healthy participants took part in our experiment, half of whom were trained by the suggested training system and the others did not use any training. All participants in the trained group succeeded in performing motor imagery after a series of trials to activate their motor cortex without any physical movements of their limbs. To confirm the effect of the suggested system, we recorded EEG signals for the trained group around sensorimotor cortex while they were imagining either left or right hand movements according to our experimental design, before and after the motor imagery training. For the control group, we also recorded EEG signals twice without any training sessions. The participants' intentions were then classified using a time-frequency analysis technique, and the results of the trained group showed significant differences in the sensorimotor rhythms between the signals recorded before and after training. Classification accuracy was also enhanced considerably in all participants after motor imagery training, compared to the accuracy before training. On the other hand, the analysis results for the control EEG data set did not show consistent increment in both the number of meaningful time-frequency combinations and the classification accuracy, demonstrating that the suggested system can be used as a tool for training motor imagery tasks in BCI applications. Further, we expect that the motor imagery training system will be useful not only for BCI applications, but for functional brain mapping studies that utilize motor imagery tasks as well.

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