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Yang SH, Wang HL, Lo YC, Lai HY, Chen KY, Lan YH, Kao CC, Chou C, Lin SH, Huang JW, Wang CF, Kuo CH, Chen YY. Inhibition of Long-Term Variability in Decoding Forelimb Trajectory Using Evolutionary Neural Networks With Error-Correction Learning. Front Comput Neurosci 2020; 14:22. [PMID: 32296323 PMCID: PMC7136463 DOI: 10.3389/fncom.2020.00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/04/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: In brain machine interfaces (BMIs), the functional mapping between neural activities and kinematic parameters varied over time owing to changes in neural recording conditions. The variability in neural recording conditions might result in unstable long-term decoding performance. Relevant studies trained decoders with several days of training data to make them inherently robust to changes in neural recording conditions. However, these decoders might not be robust to changes in neural recording conditions when only a few days of training data are available. In time-series prediction and feedback control system, an error feedback was commonly adopted to reduce the effects of model uncertainty. This motivated us to introduce an error feedback to a neural decoder for dealing with the variability in neural recording conditions. Approach: We proposed an evolutionary constructive and pruning neural network with error feedback (ECPNN-EF) as a neural decoder. The ECPNN-EF with partially connected topology decoded the instantaneous firing rates of each sorted unit into forelimb movement of a rat. Furthermore, an error feedback was adopted as an additional input to provide kinematic information and thus compensate for changes in functional mapping. The proposed neural decoder was trained on data collected from a water reward-related lever-pressing task for a rat. The first 2 days of data were used to train the decoder, and the subsequent 10 days of data were used to test the decoder. Main Results: The ECPNN-EF under different settings was evaluated to better understand the impact of the error feedback and partially connected topology. The experimental results demonstrated that the ECPNN-EF achieved significantly higher daily decoding performance with smaller daily variability when using the error feedback and partially connected topology. Significance: These results suggested that the ECPNN-EF with partially connected topology could cope with both within- and across-day changes in neural recording conditions. The error feedback in the ECPNN-EF compensated for decreases in decoding performance when neural recording conditions changed. This mechanism made the ECPNN-EF robust against changes in functional mappings and thus improved the long-term decoding stability when only a few days of training data were available.
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Affiliation(s)
- Shih-Hung Yang
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Han-Lin Wang
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Yu-Chun Lo
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Hsin-Yi Lai
- Key Laboratory of Medical Neurobiology of Zhejiang Province, Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China
| | - Kuan-Yu Chen
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Yu-Hao Lan
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Ching-Chia Kao
- Research Center for Information Technology Innovation, Academia Sinica, Taipei, Taiwan
| | - Chin Chou
- Department of Regulatory & Quality Sciences, University of Southern California, Los Angeles, CA, United States
| | - Sheng-Huang Lin
- Buddhist Tzu Chi Medical Foundation, Department of Neurology, Hualien Tzu Chi Hospital, Hualien, Taiwan
- Department of Neurology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Jyun-We Huang
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Fu Wang
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Chao-Hung Kuo
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
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Yang H, Gao W, Liu L, Liu K, Liu EH, Qi LW, Li P. Discovery of characteristic chemical markers for classification of aconite herbs by chromatographic profile and probabilistic neural network. J Pharm Biomed Anal 2015; 115:10-9. [DOI: 10.1016/j.jpba.2015.06.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/10/2015] [Accepted: 06/17/2015] [Indexed: 10/23/2022]
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Ethier C, Miller LE. Brain-controlled muscle stimulation for the restoration of motor function. Neurobiol Dis 2015; 83:180-90. [PMID: 25447224 PMCID: PMC4412757 DOI: 10.1016/j.nbd.2014.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 10/14/2014] [Accepted: 10/20/2014] [Indexed: 12/21/2022] Open
Abstract
Loss of the ability to move, as a consequence of spinal cord injury or neuromuscular disorder, has devastating consequences for the paralyzed individual, and great economic consequences for society. Functional electrical stimulation (FES) offers one means to restore some mobility to these individuals, improving not only their autonomy, but potentially their general health and well-being as well. FES uses electrical stimulation to cause the paralyzed muscles to contract. Existing clinical systems require the stimulation to be preprogrammed, with the patient typically using residual voluntary movement of another body part to trigger and control the patterned stimulation. The rapid development of neural interfacing in the past decade offers the promise of dramatically improved control for these patients, potentially allowing continuous control of FES through signals recorded from motor cortex, as the patient attempts to control the paralyzed body part. While application of these 'brain-machine interfaces' (BMIs) has undergone dramatic development for control of computer cursors and even robotic limbs, their use as an interface for FES has been much more limited. In this review, we consider both FES and BMI technologies and discuss the prospect for combining the two to provide important new options for paralyzed individuals.
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Affiliation(s)
- Christian Ethier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - Lee E Miller
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road Evanston, IL 60208, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, 345 E. Superior Ave., Chicago, IL 60611, USA.
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Kusy M, Zajdel R. Application of Reinforcement Learning Algorithms for the Adaptive Computation of the Smoothing Parameter for Probabilistic Neural Network. IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2015; 26:2163-2175. [PMID: 25532211 DOI: 10.1109/tnnls.2014.2376703] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this paper, we propose new methods for the choice and adaptation of the smoothing parameter of the probabilistic neural network (PNN). These methods are based on three reinforcement learning algorithms: Q(0)-learning, Q(λ)-learning, and stateless Q-learning. We regard three types of PNN classifiers: the model that uses single smoothing parameter for the whole network, the model that utilizes single smoothing parameter for each data attribute, and the model that possesses the matrix of smoothing parameters different for each data variable and data class. Reinforcement learning is applied as the method of finding such a value of the smoothing parameter, which ensures the maximization of the prediction ability. PNN models with smoothing parameters computed according to the proposed algorithms are tested on eight databases by calculating the test error with the use of the cross validation procedure. The results are compared with state-of-the-art methods for PNN training published in the literature up to date and, additionally, with PNN whose sigma is determined by means of the conjugate gradient approach. The results demonstrate that the proposed approaches can be used as alternative PNN training procedures.
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Neural decoding using a parallel sequential Monte Carlo method on point processes with ensemble effect. BIOMED RESEARCH INTERNATIONAL 2014; 2014:685492. [PMID: 24949462 PMCID: PMC4052147 DOI: 10.1155/2014/685492] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/17/2014] [Indexed: 11/18/2022]
Abstract
Sequential Monte Carlo estimation on point processes has been successfully applied to predict the movement from neural activity. However, there exist some issues along with this method such as the simplified tuning model and the high computational complexity, which may degenerate the decoding performance of motor brain machine interfaces. In this paper, we adopt a general tuning model which takes recent ensemble activity into account. The goodness-of-fit analysis demonstrates that the proposed model can predict the neuronal response more accurately than the one only depending on kinematics. A new sequential Monte Carlo algorithm based on the proposed model is constructed. The algorithm can significantly reduce the root mean square error of decoding results, which decreases 23.6% in position estimation. In addition, we accelerate the decoding speed by implementing the proposed algorithm in a massive parallel manner on GPU. The results demonstrate that the spike trains can be decoded as point process in real time even with 8000 particles or 300 neurons, which is over 10 times faster than the serial implementation. The main contribution of our work is to enable the sequential Monte Carlo algorithm with point process observation to output the movement estimation much faster and more accurately.
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Zhang Q, Zhang S, Hao Y, Zhang H, Zhu J, Zhao T, Zhang J, Wang Y, Zheng X, Chen W. Development of an invasive brain-machine interface with a monkey model. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11434-012-5096-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wang D, Hao Y, Zhu X, Zhao T, Wang Y, Chen Y, Chen W, Zheng X. FPGA implementation of hardware processing modules as coprocessors in brain-machine interfaces. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:4613-6. [PMID: 22255365 DOI: 10.1109/iembs.2011.6091142] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Real-time computation, portability and flexibility are crucial for practical brain-machine interface (BMI) applications. In this work, we proposed Hardware Processing Modules (HPMs) as a method for accelerating BMI computation. Two HPMs have been developed. One is the field-programmable gate array (FPGA) implementation of spike sorting based on probabilistic neural network (PNN), and the other is the FPGA implementation of neural ensemble decoding based on Kalman filter (KF). These two modules were configured under the same framework and tested with real data from motor cortex recording in rats performing a lever-pressing task for water rewards. Due to the parallelism feature of FPGA, the computation time was reduced by several dozen times, while the results are almost the same as those from Matlab implementations. Such HPMs provide a high performance coprocessor for neural signal computation.
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Affiliation(s)
- Dong Wang
- Qiushi Academy for Advanced Studies, and the Department of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
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