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Topography of human motor cortex involved in planning and action of motor tasks. Supplementary motor area labelled SMA.

Motor Imagery-based Brain Machine Interfaces

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Motor-imagery-based brain machine interfaces (MI-BMI) are devices that translate brain activity information into commands for controlling external software or hardware by using motor imagery.[1][2] Brain-machine interfaces allow users to bypass normal motor function by gathering neural data directly from the brain, and have a number of applications in research, mapping, augmentation and rehabilitation. Motor imagery or motor imagination involves mental simulation of motor actions without activation of muscles. Motor imagery provides many advantages over visually-evoked paradigms such as SSVEP and P300, as it does not require the use of stimulation devices, which often obstruct the view of the user. Therefore, motor imagery provides a promising communication and control channel between the brain and external targets that do not require the use of peripheral nerves and muscles, making it useful for individuals with serious motor disability[3]. Despite the clear advantages and convenience such a system would provide, no commercially available motor imagery-based BMI exists, and development of such an interface faces many issues, such as performance variability between subjects and limited spatial resolution of EEG.[4] It is likely that implanted electronics will demonstrate a more feasible strategy for MI-BMIs as they provide direct access to the neuronal clusters that are most involved in motor imagery activity.[5]

History

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Pioneering work on motor imagery-based BMIs was performed by Gert Pfurtscheller using EEG, who detected event-related desynchronization (ERD) localized over the contralateral hemisphere during separate movements of either hand in human subjects.[6][7] This discovery opened up the possibility of controlling brain machine interfaces with non-invasive EEG. Prior to this, study of motor imagery was performed using timers,[8] measurement of regional cerebral blood flow (rCBF) using positron emission tomography,[9] magnetic resonance imaging (MRI), and functional magnetic resonance imaging (fMRI).[10] In 2001, Pfurtscheller and Neuper demonstrated online discrimination between left-hand versus right-hand movement with a tetraplegic subject.[11] Later, they demonstrated asynchronous detection of these same activities along with a null class (no activity) using common spatial filters and linear discriminant analysis.[12] Later work provided incremental improvements to classification strategies,[13] and introduced new motor imagery tasks, such as movement of feet and tongue.[14][15] Since then, motor imagery-based BMIs have been demonstrated to be effective in restoring motor control for stroke patients,[16] with better functional outcomes observed in a split-intervention study.[17]

There has been limited performance improvements to EEG-based MI-BMIs due to physical limitations such as spatial resolution, with minor only minor improvements in number of classes. For example, separation of left foot versus right foot is challenging due to the close proximity of the regions in the brain.[18] In 2013, Yi et al. demonstrated the ability to classify both simple and compound limb motor imagery.[19] In 2019, separation of left and right foot kinaesthetic motor imagery was demonstrated using common spatial pattern.[20] The most common classes demonstrated are the left and right hands, feet (usually together, but occasionally separable), and tongue; for up to 5 motor imagery classes.

Mechanisms

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Motor imagery is a dynamic state during which a subject mentally simulates a given action[10], implying that the subject feels themselves performing a given action, usually corresponding to a first-person perspective. Imagined motor tasks can be characterized as either kinesthetic (first-person process) or visual (third-person process), with kinesthetic imagery demonstrating a clear spatial pattern in the sensorimotor regions, and visual showing less decipherable EEG patterns.[21] Brain activity during motor imagery is involved with fluctuations in sensorimotor rhythms; oscillations generated during preparation, execution and imagination of motor activity. In this case, imagination or preparation behavior can be observed as desynchronization or synchronization events in sensorimotor rhythms. Specifically, event-related desynchronization (ERD) involves a reduction in power during movement preparation or execution, and an increase in power (event-related synchronization) occurs after completing the movement. During imagery, there are contralateral ERD and ERS effects on the central and parietal lobes, with independent component analysis demonstrating localization and strong activity in the primary motor cortex.[22] Although the primary motor cortex is the main source of signals that communicate with the spine and execute movements, preparation and imagery are not exclusive to this region. The premotor cortex and supplementary motor area (SMA) are also implicated in the planning and coordination of motor actions.[23]

Motor Simulation Theory

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Motor simulation theory is a concept proposed by Marc Jeannerod as a unifying mechanism for motor cognition; explaining how action-related cognitive states relate to motor execution.[24] The theory suggests that MI works by rehearsing motor systems off-line via a hypothetical simulation process, and are based on the theoretical concept of forward modeling[25] or embodied/grounded cognition, where MI are considered to be embodied mental states.[26]

Invasive vs Noninvasive

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Non-Invasive

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Due to the cognitive nature of MI, it is difficult to verify adequate performance of MI tasks by a subject, as well as inability to provide feedback on what mental states provoke an adequate, predictable response.[27] Therefore, attempts have been made to combine MI with noninvasive technologies such as electroencephalography (EEG), functional magnetic resonance imaging (fMRI), and magnetoencephalograpy.[28]

Electroencephalography (EEG)

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The most common non-invasive method for acquisition of MI brain activity for use in BMIs is electroencephalography (EEG), which demonstrates some promise for use in rehabilitation of upper limb function after stroke.[29] EEG is able to adequately detect sensorimotor rhythms in the range of 13-15 Hz, along with the corresponding desynchronization and synchronization events that are characteristic to MI. Sensorimotor rhythms are highest in power when the corresponding sensorimotor areas are idle, and decreases when the corresponding sensory or motor areas are activated during motor imagery or motor activity. The advantages to EEG are that it is completely noninvasive, only requiring electrodes to be placed on the scalp in order to measure relative potential differences between various scalp locations as brain activity data. However, EEG is limited by the power of signals that can be recorded at the scalp surface, and also has fairly limited spatial resolution due to the size of the electrodes required for measurement and how closely they can be spaced on the scalp. Despite these limitations, EEG has been shown to be the preferred technology for uses in brain-machine interfaces due to its safety, reliability, and ease of use. Recent technological advances have allowed for improved signal acquisition through the use of lightweight, flexible electronics and dry electrodes.[30] The latest EEG designs display a trend toward wireless, wearable devices, which are preferable for day-to-day monitoring, with compact battery-powered designs over conventional bench-top amplifier boxes and hair-cap-based systems. For mobile systems, dry electrodes are preferred due to short setup times, minimal skin irritation, and excellent long-term performance.[31][32] Additionally, they perform better than gel-based EEG sensors while providing long-term wearability without reduced signal quality.[31][33]

Additional methods

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Detection of sensorimotor rhythms is also possible with magnetoencephalography, although the applications are limited due to the restrictions of magnetoencephalography as a technology. Functional MRI has also been used with EEG[34], but has not been adequately demonstrated as an adequate BMI candidate. The primary limitations are the nature of MRI and magnetoencephalography as requiring large, bulky equipment, while also requiring the operator to remain stationary in an uncomfortable position.

Invasive

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Use of EEG and other non-invasive technologies such as fMRI or magnetoencephalography are limited in their applications. The primary limitations for EEG is its bias towards peripheral neurons (neurons closest to the scalp surface), and lacks access to deeper cortical tissue. This is simply due to the inverse square law, where electrical impulses generated by neurons further away from the electrodes on the scalp surface diminish at a rate square to the distance. In addition to the surface-bias, EEG is also limited by it's spatial resolution, and is unable to target neurons individually, or even as groups or clusters. The EEG gathered at the scalp surface include the sum of activity across the brain, although mostly representative of post-synaptic potentials in the superficial cortex. This means that any single point on the scalp represents a blurred image of what's going on under the surface. A common means to get around this limitation is to use large clusters of electrodes; as many as (but not limited to) 256 electrodes, and then attempt to use advanced preprocessing and feature extraction methods to extract the most relevant information, or attempt to heuristically invert the data to determine what parts of the brain contribute to what signals.

Alternatively, in order to achieve the best possible signal, researchers may attempt to bypass the barriers protecting the brain, and attempt to place electrodes on or within the brain itself. This results in highly localized and high quality signals with consistent impedances, as well as access to deeper tissue. Depending on the electrode sizes, they may be able to capture action potentials from single neurons or small neuronal clusters. This results in a significantly higher resolution and the capability to target individual clusters with great precision. The major drawbacks from such invasive systems are the requirements for costly and risky surgeries, as well as the use of expensive cutting edge devices that will need to survive the harsh environment of the brain; where the fluid can often cause corrosion and deterioration in many electronic and housing materials. Building robust implantable electronics is the primary challenge to development of future invasive brain-machine interface solutions.

Electrocorticography (ECoG)

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Electrocorticography involves the use of electrodes placed on the exposed brain surface, providing localized, high quality signals of brain electrical activity. Due to the surface placement of the electrodes, ECoG is limited by the surface neurons. In the case of motor imagery-based BMIs, surface access to the motor cortex provides adequate coverage of important motor pathways to allow for implementation of MI as a paradigm.[35]

Additional Methods

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Deep brain stimulation and cortical implants are at the forefront of BMI development, allowing for access to neurons deeper in the cortex, as well as allowing for neural feedback through neurostimulation[5]. Companies such as Neuralink are actively developing implantable brain-machine interfaces that can actively target various neurons using up to 1500 electrodes, and will likely be able to support a greater number of tasks when compared with its EEG-based counterparts.[36]

Classification of Motor Imagery EEG Data

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EEG is the foremost method for integration and classification of motor imagery due to its safety and ease of use. The primary challenge when integrating an EEG-based brain-machine interface is the processing and classification of raw EEG signals. A number of feature extraction, feature selection and classification techniques have been developed for the classification of EEG-based motor imagery, with varying degrees of success. A sampling of research papers demonstrating classification of MI-based BMIs is shown in the table below.

Performance comparison between various MI-BMI systems
Year Accuracy (%) Number of Electrodes Number of Classes Length (s) Number of Subjects Information transfer rate (bits/min)
2019[37] 83.0 22 4 4 9 16.09*
2017[38] 86.41 ± 0.77 28 2 3 2 8.53 ± 0.42*
2016[39] 77.6 ± 2.1 3 2 2 9 6.98 ± 1.18*
2016[40] 84.0 3 2 2 9 10.97*
2019[41] 95.4 128 4 2 9 49.74*
2017[42] 84.0 44 4 4 9 16.68*

Processing of raw EEG data begins with selection of signal processing techniques. Signal processing and feature extraction techniques include filtering, autoregressive modeling, fast-Fourier transforms, and other frequency-domain based techniques. Additionally, time-frequency domain techniques are also used as it reveals spectral information about the EEG; including the use of short-time Fourier transform (STFT), wavelet transform, and discrete wavelet transform[43]. Decomposition methods using wavelets are useful as EEG contains various frequency bands containing different information about motor imagery. These methods are excellent for deriving dynamic features due to EEG being non-linear and non-Gaussian.[43] Another commonly used method for extracting features are common spatial patterns (CSP). CSPs are commonly used to classify MI EEG, as different frequency bands of EEG contain different information, and CSP enables extraction of this information from different bands. Variations of CSP when combined with strong classification methods such as linear discriminant analysis or support vector machines have demonstrated some of the best classification accuracies in published literature. However, since the emergence of convolutional neural networks as a powerful feature extraction and classification strategy for EEG signals[44], it has been demonstrated to have some of the best performances when compared with conventional feature extraction and classification methods.[45][46]

Advantages and Disadvantages

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Motor imagery (MI) is a greatly advantageous paradigm for persistent BMI when compared to evoked paradigms as it does not require the use of external stimuli; its classes are based on imagined motor activities such as opening and closing a hand or moving feet[47][48][49]. Additionally, trained subjects are able to rapidly switch between motor imagery tasks, allowing for lower latencies between tasks when compared with visually-evoked paradigms. Motor imagery can also be acquired with relatively few electrodes when compared with other BCI methods. Finally, use of improved training techniques such as neurofeedback and immersive virtual reality training may allow for more efficient and consistent training with less responsive subjects.

Performance Variation

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The performance of a MI-based BCI is heavily dependent on the state of the user, with high intra- and inter- subject variability in classification performance. There is a strong relationship between signal quality and the mental state of the user, with fatigue or drowsiness in test subjects yielding poorer results.[4] Evidence suggests that low-performance groups have a less-developed brain network for motor imagery, resulting in poorer performance.[4] Due to limited intra-subject and clinical studies, it is unclear what strategies may be used to improve performance with BMIs.[2][4]

Applications

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Applications for motor imagery-based BMIs are limited by the number of classes that can be classified, and are used in both control and monitoring applications.[50] Control applications involve the manipulation of external devices, such as a vehicle or a prosthetic device, while monitoring involves the determination of the mental or emotional state of the user. Biomedical applications of BCI include the replacement or restoration of central nervous system (CNS) functionality that is lost due to disease or injury. Illnesses such as stroke or amyotrophic lateral sclerosis (ALS), paralysis, amputations, and traumatic injury may result in permanent loss of motor capability. BCI-based prosthetics have previously been demonstrated using paradigms such as SSVEP.[51] Motor imagery-based prosthetics with up to 5 degrees of freedom have also been demonstrated[52][53], but are limited by performance variations, with subject-to-subject accuracy ranging from 56% to 100%.[50][52] Motor imagery and neurofeedback-based BCIs have also shown promise for rehabilitation of motor function after injury or illness due to the active involvement in neural plasticity and development. MI-BMIs have been demonstrated to promote clinical and neurophysiological changes in stroke patients through the use of neurofeedback training over extended periods.[54] Further uses in therapy and assessment have shown that incorporation of virtual reality (VR) to provide visual feedback to the user, allowing them to safely navigate virtual environments, creating a more immersive neurofeedback environment.[50]

References

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  1. ^ Lebedev, Mikhail A.; Nicolelis, Miguel A.L. (2006-09-XX). "Brain–machine interfaces: past, present and future". Trends in Neurosciences. 29 (9): 536–546. doi:10.1016/j.tins.2006.07.004. {{cite journal}}: Check date values in: |date= (help)
  2. ^ a b Hamedi, Mahyar; Salleh, Sh-Hussain; Noor, Alias Mohd (2016-06-XX). "Electroencephalographic Motor Imagery Brain Connectivity Analysis for BCI: A Review". Neural Computation. 28 (6): 999–1041. doi:10.1162/NECO_a_00838. ISSN 0899-7667. {{cite journal}}: Check date values in: |date= (help)
  3. ^ Wolpaw, Jonathan R; Birbaumer, Niels; McFarland, Dennis J; Pfurtscheller, Gert; Vaughan, Theresa M (2002-06-XX). "Brain–computer interfaces for communication and control". Clinical Neurophysiology. 113 (6): 767–791. doi:10.1016/S1388-2457(02)00057-3. {{cite journal}}: Check date values in: |date= (help)
  4. ^ a b c d "Performance variation in motor imagery brain–computer interface: A brief review". Journal of Neuroscience Methods. 243: 103–110. 2015-03-30. doi:10.1016/j.jneumeth.2015.01.033. ISSN 0165-0270.
  5. ^ a b "Groundbreaking implant wirelessly relays brain signals in high fidelity". New Atlas. 2021-04-06. Retrieved 2021-05-05.
  6. ^ Pfurtscheller, Gert; Neuper, Christa (1997-12-XX). "Motor imagery activates primary sensorimotor area in humans". Neuroscience Letters. 239 (2–3): 65–68. doi:10.1016/S0304-3940(97)00889-6. {{cite journal}}: Check date values in: |date= (help)
  7. ^ Pfurtscheller, G.; Brunner, C.; Schlögl, A.; Lopes da Silva, F.H. (2006-05-XX). "Mu rhythm (de)synchronization and EEG single-trial classification of different motor imagery tasks". NeuroImage. 31 (1): 153–159. doi:10.1016/j.neuroimage.2005.12.003. {{cite journal}}: Check date values in: |date= (help)
  8. ^ Decety, Jean; Boisson, Dominique (1990-09-01). "Effect of brain and spinal cord injuries on motor imagery". European Archives of Psychiatry and Clinical Neuroscience. 240 (1): 39–43. doi:10.1007/BF02190091. ISSN 1433-8491.
  9. ^ "Europe PMC". europepmc.org. Retrieved 2021-05-04.
  10. ^ a b Decety, Jean (1996-05-01). "The neurophysiological basis of motor imagery". Behavioural Brain Research. 77 (1): 45–52. doi:10.1016/0166-4328(95)00225-1. ISSN 0166-4328.
  11. ^ Pfurtscheller, G.; Neuper, C. (2001-07-XX). "Motor imagery and direct brain-computer communication". Proceedings of the IEEE. 89 (7): 1123–1134. doi:10.1109/5.939829. ISSN 1558-2256. {{cite journal}}: Check date values in: |date= (help)
  12. ^ Townsend, G.; Graimann, B.; Pfurtscheller, G. (2004-06-XX). "Continuous EEG classification during motor imagery-simulation of an asynchronous BCI". IEEE Transactions on Neural Systems and Rehabilitation Engineering. 12 (2): 258–265. doi:10.1109/TNSRE.2004.827220. ISSN 1558-0210. {{cite journal}}: Check date values in: |date= (help)
  13. ^ "ShieldSquare Captcha". doi:10.1088/1741-2560/1/3/002/meta. {{cite journal}}: Cite journal requires |journal= (help)
  14. ^ Yi, Weibo; Qiu, Shuang; Qi, Hongzhi; Zhang, Lixin; Wan, Baikun; Ming, Dong (2013-10-12). "EEG feature comparison and classification of simple and compound limb motor imagery". Journal of NeuroEngineering and Rehabilitation. 10 (1): 106. doi:10.1186/1743-0003-10-106. ISSN 1743-0003. PMC 3853015. PMID 24119261.{{cite journal}}: CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link)
  15. ^ "Classification of multiple motor imagery using deep convolutional neural networks and spatial filters". Applied Soft Computing. 75: 461–472. 2019-02-01. doi:10.1016/j.asoc.2018.11.031. ISSN 1568-4946.
  16. ^ Ang, Kai Keng; Guan, Cuntai; Chua, Karen Sui Geok; Ang, Beng Ti; Kuah, Christopher; Wang, Chuanchu; Phua, Kok Soon; Chin, Zheng Yang; Zhang, Haihong (2009-09-XX). "A clinical study of motor imagery-based brain-computer interface for upper limb robotic rehabilitation". 2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society: 5981–5984. doi:10.1109/IEMBS.2009.5335381. {{cite journal}}: Check date values in: |date= (help)
  17. ^ Pichiorri, Floriana; Morone, Giovanni; Petti, Manuela; Toppi, Jlenia; Pisotta, Iolanda; Molinari, Marco; Paolucci, Stefano; Inghilleri, Maurizio; Astolfi, Laura; Cincotti, Febo; Mattia, Donatella (2015). "Brain–computer interface boosts motor imagery practice during stroke recovery". Annals of Neurology. 77 (5): 851–865. doi:10.1002/ana.24390. ISSN 1531-8249.
  18. ^ Sakhavi, Siavash; Guan, Cuntai; Yan, Shuicheng (2015-08-XX). "Parallel convolutional-linear neural network for motor imagery classification". 2015 23rd European Signal Processing Conference (EUSIPCO): 2736–2740. doi:10.1109/EUSIPCO.2015.7362882. {{cite journal}}: Check date values in: |date= (help)
  19. ^ Yi, Weibo; Qiu, Shuang; Qi, Hongzhi; Zhang, Lixin; Wan, Baikun; Ming, Dong (2013-10-12). "EEG feature comparison and classification of simple and compound limb motor imagery". Journal of NeuroEngineering and Rehabilitation. 10 (1): 106. doi:10.1186/1743-0003-10-106. ISSN 1743-0003. PMC 3853015. PMID 24119261.{{cite journal}}: CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link)
  20. ^ Tariq, Madiha; Trivailo, Pavel M; Simic, Milan (2019-11-25). "Classification of left and right foot kinaesthetic motor imagery using common spatial pattern". Biomedical Physics & Engineering Express. 6 (1): 015008. doi:10.1088/2057-1976/ab54ad. ISSN 2057-1976.
  21. ^ "Imagery of motor actions: Differential effects of kinesthetic and visual–motor mode of imagery in single-trial EEG". Cognitive Brain Research. 25 (3): 668–677. 2005-12-01. doi:10.1016/j.cogbrainres.2005.08.014. ISSN 0926-6410.
  22. ^ Duann, Jeng-Ren; Chiou, Jin-Chern (2016). "A Comparison of Independent Event-Related Desynchronization Responses in Motor-Related Brain Areas to Movement Execution, Movement Imagery, and Movement Observation". PloS One. 11 (9): e0162546. doi:10.1371/journal.pone.0162546. ISSN 1932-6203. PMC 5026344. PMID 27636359.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  23. ^ "Motor imagery". Journal of Physiology-Paris. 99 (4–6): 386–395. 2006-06-01. doi:10.1016/j.jphysparis.2006.03.012. ISSN 0928-4257.
  24. ^ Jeannerod, M. (2001-07). "Neural simulation of action: a unifying mechanism for motor cognition". NeuroImage. 14 (1 Pt 2): S103–109. doi:10.1006/nimg.2001.0832. ISSN 1053-8119. PMID 11373140. {{cite journal}}: Check date values in: |date= (help)
  25. ^ Flanagan, J. Randall; Vetter, Philipp; Johansson, Roland S.; Wolpert, Daniel M. (2003-01-21). "Prediction Precedes Control in Motor Learning". Current Biology. 13 (2): 146–150. doi:10.1016/S0960-9822(03)00007-1. ISSN 0960-9822.
  26. ^ Lorey, Britta; Bischoff, Matthias; Pilgramm, Sebastian; Stark, Rudolf; Munzert, Jörn; Zentgraf, Karen (2009-04-XX). "The embodied nature of motor imagery: the influence of posture and perspective". Experimental Brain Research. 194 (2): 233–243. doi:10.1007/s00221-008-1693-1. ISSN 0014-4819. {{cite journal}}: Check date values in: |date= (help)
  27. ^ Kaiser, Vera; Kreilinger, Alex; Mueller-Putz, Gernot R.; Neuper, Christa (2011). "First Steps Toward a Motor Imagery Based Stroke BCI: New Strategy to Set up a Classifier". Frontiers in Neuroscience. 5. doi:10.3389/fnins.2011.00086. ISSN 1662-453X.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  28. ^ Carvalho, Raquel; Dias, Nuno; Cerqueira, João José (2019-04-XX). "Brain‐machine interface of upper limb recovery in stroke patients rehabilitation: A systematic review". Physiotherapy Research International. 24 (2): e1764. doi:10.1002/pri.1764. ISSN 1358-2267. {{cite journal}}: Check date values in: |date= (help)
  29. ^ Monge-Pereira, Esther; Ibañez-Pereda, Jaime; Alguacil-Diego, Isabel M.; Serrano, Jose I.; Spottorno-Rubio, María P.; Molina-Rueda, Francisco (2017-09-XX). "Use of Electroencephalography Brain-Computer Interface Systems as a Rehabilitative Approach for Upper Limb Function After a Stroke: A Systematic Review". PM&R. 9 (9): 918–932. doi:10.1016/j.pmrj.2017.04.016. {{cite journal}}: Check date values in: |date= (help)
  30. ^ Lim, Hyo‐Ryoung; Kim, Hee Seok; Qazi, Raza; Kwon, Young‐Tae; Jeong, Jae‐Woong; Yeo, Woon‐Hong (2020-04-XX). "Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment". Advanced Materials. 32 (15): 1901924. doi:10.1002/adma.201901924. ISSN 0935-9648. {{cite journal}}: Check date values in: |date= (help)
  31. ^ a b "A 3D printed dry electrode for ECG/EEG recording". Sensors and Actuators A: Physical. 174: 96–102. 2012-02-01. doi:10.1016/j.sna.2011.12.017. ISSN 0924-4247.
  32. ^ "Towards gel-free electrodes: A systematic study of electrode-skin impedance". Sensors and Actuators B: Chemical. 241: 1244–1255. 2017-03-31. doi:10.1016/j.snb.2016.10.005. ISSN 0925-4005.
  33. ^ Stauffer, Flurin; Thielen, Moritz; Sauter, Christina; Chardonnens, Séverine; Bachmann, Simon; Tybrandt, Klas; Peters, Christian; Hierold, Christofer; Vörös, Janos (2018). "Skin Conformal Polymer Electrodes for Clinical ECG and EEG Recordings". Advanced Healthcare Materials. 7 (7): 1700994. doi:10.1002/adhm.201700994. ISSN 2192-2659.
  34. ^ "Real-time EEG feedback during simultaneous EEG–fMRI identifies the cortical signature of motor imagery". NeuroImage. 114: 438–447. 2015-07-01. doi:10.1016/j.neuroimage.2015.04.020. ISSN 1053-8119.
  35. ^ Liu, Chong; Zhao, Hai-bin; Li, Chun-sheng; Wang, Hong (2010-10-XX). "Classification of ECoG motor imagery tasks based on CSP and SVM". 2010 3rd International Conference on Biomedical Engineering and Informatics. 2: 804–807. doi:10.1109/BMEI.2010.5639943. {{cite journal}}: Check date values in: |date= (help)
  36. ^ Markoff, John (2019-07-17). "Elon Musk's Neuralink Wants 'Sewing Machine-Like' Robots to Wire Brains to the Internet". The New York Times. ISSN 0362-4331. Retrieved 2021-05-05.
  37. ^ "ShieldSquare Captcha". hkvalidate.perfdrive.com. doi:10.1088/1741-2552/ab3471/meta. Retrieved 2021-05-05.
  38. ^ "Single-trial EEG classification of motor imagery using deep convolutional neural networks". Optik. 130: 11–18. 2017-02-01. doi:10.1016/j.ijleo.2016.10.117. ISSN 0030-4026.
  39. ^ "ShieldSquare Captcha". hkvalidate.perfdrive.com. doi:10.1088/1741-2560/14/1/016003/meta. Retrieved 2021-05-05.
  40. ^ Lu, Na; Li, Tengfei; Ren, Xiaodong; Miao, Hongyu (2017-06). "A Deep Learning Scheme for Motor Imagery Classification based on Restricted Boltzmann Machines". IEEE transactions on neural systems and rehabilitation engineering: a publication of the IEEE Engineering in Medicine and Biology Society. 25 (6): 566–576. doi:10.1109/TNSRE.2016.2601240. ISSN 1558-0210. PMID 27542114. {{cite journal}}: Check date values in: |date= (help)
  41. ^ "Deep Learning for EEG motor imagery classification based on multi-layer CNNs feature fusion". Future Generation Computer Systems. 101: 542–554. 2019-12-01. doi:10.1016/j.future.2019.06.027. ISSN 0167-739X.
  42. ^ Schirrmeister, Robin Tibor; Springenberg, Jost Tobias; Fiederer, Lukas Dominique Josef; Glasstetter, Martin; Eggensperger, Katharina; Tangermann, Michael; Hutter, Frank; Burgard, Wolfram; Ball, Tonio (2017-11). "Deep learning with convolutional neural networks for EEG decoding and visualization". Human Brain Mapping. 38 (11): 5391–5420. doi:10.1002/hbm.23730. ISSN 1097-0193. PMC 5655781. PMID 28782865. {{cite journal}}: Check date values in: |date= (help)
  43. ^ a b "Comparison of signal decomposition methods in classification of EEG signals for motor-imagery BCI system". Biomedical Signal Processing and Control. 31: 398–406. 2017-01-01. doi:10.1016/j.bspc.2016.09.007. ISSN 1746-8094.
  44. ^ "Deep convolutional neural network for the automated detection and diagnosis of seizure using EEG signals". Computers in Biology and Medicine. 100: 270–278. 2018-09-01. doi:10.1016/j.compbiomed.2017.09.017. ISSN 0010-4825.
  45. ^ Chaudhary, Shalu; Taran, Sachin; Bajaj, Varun; Sengur, Abdulkadir (2019-06-XX). "Convolutional Neural Network Based Approach Towards Motor Imagery Tasks EEG Signals Classification". IEEE Sensors Journal. 19 (12): 4494–4500. doi:10.1109/JSEN.2019.2899645. ISSN 1558-1748. {{cite journal}}: Check date values in: |date= (help)
  46. ^ "Deep Learning for EEG motor imagery classification based on multi-layer CNNs feature fusion". Future Generation Computer Systems. 101: 542–554. 2019-12-01. doi:10.1016/j.future.2019.06.027. ISSN 0167-739X.
  47. ^ "EEG-based discrimination between imagination of right and left hand movement". Electroencephalography and Clinical Neurophysiology. 103 (6): 642–651. 1997-12-01. doi:10.1016/S0013-4694(97)00080-1. ISSN 0013-4694.
  48. ^ "ShieldSquare Captcha". doi:10.1088/1741-2552/ab3471/meta. {{cite journal}}: Cite journal requires |journal= (help)
  49. ^ "Motor imagery EEG recognition based on conditional optimization empirical mode decomposition and multi-scale convolutional neural network". Expert Systems with Applications. 149: 113285. 2020-07-01. doi:10.1016/j.eswa.2020.113285. ISSN 0957-4174.
  50. ^ a b c Padfield, Natasha; Zabalza, Jaime; Zhao, Huimin; Masero, Valentin; Ren, Jinchang (2019/1). "EEG-Based Brain-Computer Interfaces Using Motor-Imagery: Techniques and Challenges". Sensors. 19 (6): 1423. doi:10.3390/s19061423. {{cite journal}}: Check date values in: |date= (help)CS1 maint: unflagged free DOI (link)
  51. ^ Müller-Putz, Gernot R.; Pfurtscheller, Gert (2008-01). "Control of an electrical prosthesis with an SSVEP-based BCI". IEEE transactions on bio-medical engineering. 55 (1): 361–364. doi:10.1109/TBME.2007.897815. ISSN 0018-9294. PMID 18232384. {{cite journal}}: Check date values in: |date= (help)
  52. ^ a b Elstob, Daniel; Secco, Emanuele Lindo (2016-03-09). "A Low Cost Eeg Based Bci Prosthetic Using Motor Imagery". arXiv:1603.02869 [cs].
  53. ^ Müller-Putz, G. R.; Ofner, P.; Schwarz, A.; Pereira, J.; Luzhnica, G.; di Sciascio, C.; Veas, E.; Stein, S.; Williamson, J. (2017-09-18). "Moregrasp: Restoration of Upper Limb Function in Individuals with High Spinal Cord Injury by Multimodal Neuroprostheses for Interaction in Daily Activities". eprints.gla.ac.uk. Retrieved 2021-05-05.
  54. ^ Carvalho, Raquel; Dias, Nuno; Cerqueira, João José (2019). "Brain-machine interface of upper limb recovery in stroke patients rehabilitation: A systematic review". Physiotherapy Research International. 24 (2): e1764. doi:10.1002/pri.1764. ISSN 1471-2865.