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2014 Vol. 33, No. 6
Published: 2014-12-20
641
Brain Computer Interface: Translation from Miracle to Reality
YAO De Zhong
#*
DOI: 10.69/j.issn.0258-8021.2014.06.01
Braincomputer interface (BCI) is the technique which uses online brainsignal processing to enhance the interactions between human and environments. This article summarizes the main aspects of BCI, and the challenges for BCI from miracle to reality
2014 Vol. 33 (6): 641-643 [
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550
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644
Key Techniques in Motor Imagery Based BrainComputer Interface
LIU Tie Jun
#
ZHANG Rui XU Peng
#*
DOI: 10.3969/j.issn.0258-8021.2014.06.02
Motor imagery based braincomputer interface (MI BCI) has been considered as the most promising BCI in practical application. However, several urgent problems need to be solved for MI BCI. Based on our research experience in past several years, this paper discusses the developed methods in our group for signal acquisition, feature extraction, pattern recognition and online BCI system. As for the acquisition aspect, we designed an amplifier that can remove the DC offset effectively. Several improved algorithms based on common spatial pattern (CSP) are developed to increase the immunity to noises. As for pattern recognition, several variants of linear discriminative analysis are developed to improve the recognition rates. Based on those methods, we built a hybrid online BCI system that combined motor imagery and motion onset visual evoked potential (MOVEP).
2014 Vol. 33 (6): 644-651 [
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773
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652
The CrossBrain Neurofeedback Platform with High Ecological Validity#br#
LIU Wei Jie
1
DUAN Lian
1
DAI Rui Na
1
XIAO Xiang
1
LI Zheng
1
DOI: 10.3969/j.issn.0258-8021.2014.06.03
In this work we proposed a novel concept of crossbrain neurofeedback, extending neurofeedback research from regulation of neural activities of a single brain to that of neural synchronization of two interacting brains. This article describes the design and implementation of two sets of functional nearinfrared spectroscopy (fNIRS) based twoperson neurofeedback platforms with high ecological validity: 1) platform based on a single fNIRS recording system at one location and 2) an internetbased platform connecting two fNIRS recording systems at different locations. Each platform simultaneously records two participants’ neural signals, calculates the neural synchronization index in realtime, and feeds back the index to the participants through a visualization. The feedback information enables participants to try different regulation strategies to voluntarily control their neural synchronization, which may lead to changes in social cognition and behavior. In an application of single fNIRS based platform, HbO signals in the specific brain regions of two subjects were so much alike, indicating that their neuro activities were synchronized. Moreover, in preliminary experiment for the internetbased platform, two subjects performed collaboration task. The ball in the most of the time is maintained between two dotted lines, which implied two subjects were in synchronization. Preliminary experiments demonstrating that both participants successfully regulated and synchronized their brain activities in a social interaction situation validate our fNIRSbased crossbrain neurofeedback platform.
2014 Vol. 33 (6): 652-658 [
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493
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659
A Review on Invasive Brain Machine Interface
CAO Yan
1,2
ZHENG XiaoXiang
1,2,3#*
DOI: 10.3969/j.issn.0258-8021.2014.06.04
The brain machine interface establishes a new communication and control pathway between the brain and external devices. It provides a new approach to understand more about the structure and function of brain. On the other hand, it is a possible treatment to restore the movement functions for patients. Invasive brain machine interface can realize elaborate motion control with the high spatial and temporal resolution of tremendous information embedded in the neural firings. Therefore it emerges as an interdisciplinary research area and attracts more attention. The paper reviews the development of invasive brain machine interface, especially on neural acquisition, movement decoding and artificial sensory feedback.
2014 Vol. 33 (6): 659-665 [
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547
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666
Motor Imagery Signal Classification Based on HDP AR HMM
WU Jun
1
YANG Ya
2
YU ZhuLiang
1#*
GU Zheng Hui
1
LI YuanQing
1#
DOI: 10.3969/j.issn.0258-8021.2014.06.05
Hidden Markov model (HMM) is well applied in brain computer interface, especially in the classification of motor imagery(MI) electroencephalogram (EEG) signal. Conventional methods use HMM to model EEG signal, then use the observed signal under controlled state to estimate the HMM parameters and finally classify the EEG signal through the trained HMMs. However, due to the characteristics of low signaltonoise ratio(SNR), high dimensionality and complexity of motor imagery EEG signal, HMM cannot fully describe the dynamic property of motor imagery EEG signal. In this paper, we use hierarchical Dirichlet process (HDP) with selfclustering ability to describe MI signals and then use AR/VAR model to highlight the time property of MI signal. Finally we combine them with Markov switching processing (MSP) so that we can get more information of MI signal. In order to verify this method, we tested the algorithm on our inhouse data and some of the 2003 BCI international competition data sets. High accuracy on classification of MI is obtained.
2014 Vol. 33 (6): 666-672 [
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401
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673
Neural Substrates of Music Investigated by EEG and fMRI
YAO De Zhong
#*
WU Dan LAI Yong Xiu GONG Dian Kun LUO Cheng LU Jing MA Wei Yi YANG Hua XU Peng
DOI: 10.3969/j.issn.0258-8021.2014.06.06
Music is a special crosscultural artistic style that appeared and evolved along with the development of the human being. The exploration of the mystery in music and the relation between music and brain is a way to understand humanity itself, thus it is a very charming area for science and society. In this paper, based on our experiences, examples are presented on studies of music note attribute cognition, brain network of musician and brain wave music. We hope that these primary results are helpful for the readers in their future efforts.
2014 Vol. 33 (6): 673-676 [
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508
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677
Multiintensity Edge Detection for Colony Images Based on the Function of Photoreceptor in Visual System #br#
LUO Jia Jun WU Wei
*
FAN Ying Le GAO Yun Yuan
DOI: 10.3969/j.issn.0258-8021.2014.06.07
Considering the superiority of visual nervous system in contour perception, a new method of image edge detection based on the function of photoreceptor in visual system was proposed in this paper. Firstly, the neural network was constructed with leaky integrateandfire (LIF) neuronal electrophysiological model. Secondly, each neuron would be classified as excitation (ON) type or inhibition (OFF) type according to the neural firing pattern. And then the weak edges were highlighted by using centersurround antagonistic receptive field feature and feedback enhancing mode of neuronal excitation. Meanwhile the image movement in multidirection and multiscale was applied to overcome the adaptability of photoreceptor and highlight the contrast of weak details. Finally the edge image was acquired by fusing the variance information, such as photosensitive neural network’s firing rates. In this paper, twenty colony images having rich details in the edge were selected as experimental samples. The results of multiintensity edge detection were assessed by the confidence of edge and reconstruction similarity. It was proved that the new method can effectively detect the intact multiintensity edge image, especially the means of reconstruction similarity in the weak edge detection is improved significantly, which is higher than 08 (P<005). The method of edge detection discussed in this paper provides a brandnew idea for multiintensity edge details image processing based on the feature of physiological visual.
2014 Vol. 33 (6): 677-686 [
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319
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687
Automatic Analysis Method of Macular Edema Classification for Diabetic Retinopathy Images#br#
ZHENG Shao Hua
*
CHEN Jian PAN Lin YU Lun
DOI: 10.3969/j.issn.0258-8021.2014.06.08
Diabetic macular edema (DME) can appear in any stage of the diabetic retinopathy (DR) and is the leading cause of vision impairment in people with diabetes. Therefore, the automatic analysis of DME plays a key role in the DR screening program. According to the DME international clinical classification standard, detecting and judging the presence of hard exudates (HEs) close or relate to macula fovea (MF) is a standard method to assess DME in the fundus images. A synthetic improvement method based on existing mathematical morphology technique is selected for HEs detection. A novel method of macular fovea center location is proposed based on the directional local contrast filter and the local vessel density. Then the optic disk region can be easily located and removed for reducing the impact to the HEs detection. Only the large vessel segmentations were used for the vessel density calculation. From the testing results on the 169 images from HEIMED public dataset, the sensitivity and specificity of HEs detection on image level are 100% and 922%, respectively. The accuracy of macular fovea center location reaches 982%. And the accuracy for each DME classification is more than 88%. The proposed method would have important clinical application potentials.
2014 Vol. 33 (6): 687-695 [
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462
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696
Corticomuscular Synchronization Analysis Based on Granger Causality during Walking#br#
NIU Xiao Chen
1
CHEN Xiao Ling
1
CHEN Ying Ya
1
WU Xiao Guang
1
DU Yi Hao
2
XIE Ping
1*
DOI: 10.3969/j.issn.0258-8021.2014.06.09
The aim of this study is to investigate functional relationship between brain cortex and muscles during walking and explore the differences of the functional relationships between forward and backward walking. This article collects the EEG and EMG datasets which acquired simultaneously from 10 healthy subjects during forward and backward walking. Granger causality (GC) method, which can reveal the coupling connection and information flow direction among two signals, was applied to analyze the EEG and surface EMG data. Further, the EEGEMG significant GC area was defined to quantitatively describe the corticomuscular function coupling and information flow direction of different muscles at different frequencies. Then the EEG spectral power was calculated to analyze the relationship with corticomuscular function coupling. The results of Wilcoxon test show that during backward walking, the EEG→EMG and EMG→EEG significant GC area indexes of rectus femoris and tibialis anterior muscle were lower compared with forward walking(α=005, P<005), and a linear relationship exists between EEG spectral power peak and GC peak at EEG→EMG based on linear regression analysis(α=005, P<005). These illustrate that there exists directed coupling between EEG and EMG during walking, and alpha and beta rhythm involve the control and feedback process of walking. It verifies that the proposed methods can further describe the synchronization feature and functional connection between cortex and muscles.
2014 Vol. 33 (6): 696-706 [
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307
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707
Sample Entropy Evaluation of EEG complexity Based on Low Frequency Photon Stimulation in Light Sleep
ZHOU Hui TAO Ling
*
QIAN Zhi Yu ZHAO Cui Hua
DOI: 10.3969/j.issn.0258-8021.2014.06.010
Patients with sleep disorders have difficulties entering deep sleep from light sleep. It is important to research the changes of EEG during the light sleep for sleep efficiency and quality. In this paper, the EEG response during the light sleep under photon stimulation was studied by analyzing the EEG complexity changes, and the impact of photon stimulation on sleep EEG was studied as well. Ten volunteers’ EEG data during photon stimulation and normal sleep were gained by Neuroscan. Firstly, the EEG data of light sleep were obtained by using timefrequency analysis. Secondly, the theta waves, delta waves, alpha waves and the spindles were extracted from the EEG by using wavelet packet decomposition. Thirdly, the complexity of EEG and its components with different frequencies during the light sleep were calculated by using sample entropy. Lastly, the light sleep EEG complexity between normal sleep and photon stimulation(5 Hz)sleep was compared to research the impact of photon stimulation. We found the average value of EEG complexity under photon stimulation is 0514 15,significantly less than the average value of normal sleep, 0589 23, especially in central and parietal region(P<005). The conclusion is that photon stimulation(5Hz)can induce the synchronous response of EEG, and strengthen the EEG rhythm, which helps the brain enter deep sleep.
2014 Vol. 33 (6): 707-714 [
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389
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715
A Human Body Modeling for Risk Factors of Chronic Disease with an Artificial Neural Network
BAO Jia Ming
1
WANG Shun
2
ZHU Chao Yang
2
WANG Yi Qing
1
XU Ya Shi
1
WANG Qiang
2
DOI: 10.3969/j.issn.0258-8021.2014.06.011
The aim of this study is to set up an individualized modeling method, based on the back propagation (BP) learning algorithm on an artificial neural network (ANN), for a risk factor control of chronic disease. The inputs of the model include the parameters about physical activity, food intake (salt, grains, vegetables, fruits, meat and poultry, eggs, fish, legumes, milk, oil, animal internal organs), drinking and smoking. And the outputs are systolic pressure, diastolic pressure, glucose, heart rate and BMI. The reliability of the model was test by residual analysis. The result showed that coincidence rates of measured outputs with the estimated ones of 9 models were over 80% among 13 volunteers. So it is concluded that the proposed method is generally practical, providing a basis for the design of individualized state control of chronic disease risk factor.
2014 Vol. 33 (6): 715-721 [
Abstract
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304
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722
Depthcontrolled and Automated Piezoelectric Micro issection System
ZHU Jun Hui
1
WANG Yong
1
ZHU Meng
1
CHEN Rui Hua
2*
RU Chang Hai
1*
DOI: 10.969/j.issn.0258-021.2014.6.12
In order to obtain a specific population of cells or a single cell from different tissue slice for the research, a depthcontrolled and automated piezoelectric microdissection system was developed to solve problems of time consuming, easy fatigue, and low accuracy in the manualdissection. On the basis of different gray values of foreground and background to detect and track the tip of the dissection needle〖DK〗’s position in rea
ltime, and according to the change of the X axis to judge whether the dissection needle contact the target surface, the depth information was acquired. By analyzing the dissection experiments conducted in different conditions, it is shown that this proposed system can place the needle in any positions of the tissues, quickly scan the whole samples to determine the target area and realize the dissection in specify position with arbitrary shape of biological samples. The fineness of cutting line is 15 μm, the resolution of cutting is 50 nm,and cutting error is 05 μm, reaching the unicellular cut level. In addition, the separation of target tissue sections can be realized automatically. The method provides the improvement of the precision and efficiency of dissections, showing its superiority.
2014 Vol. 33 (6): 722-728 [
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378
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729
Biomechanical Effect of an Interspinous Process Spacer for L4/5 of Lower Lumbar: a Finite Element Analysis#br#
CAI Fang Zhou
1,2
GU Xue Lian
1*
HAN Shou Peng
2
SONG Cheng Li
1
Chen Bo
3
DOI: 10.3969/j.issn.0258-8021.2014.06.013
To analyze the effect of the stability of an implanted homologous XSTOP device in the injury segment L4/5 and the biomechanical behavior of adjacent segments. A CTscanner was used to acquire normal lumbar images. With the help of Mimics14, Geomagic Studio2012, Hypermesh12 and Abaqus612-1, the finite element (FE) model (the lower lumbar L2~L5 segments) with or without interspinous spacer XSTOP was constructed. Upon validation, a finite element model of L2~L5 was developed to simulate and analyze the biomechanics of the intact and XSTOP dynamic fixation states by simulating flexion, extension, lateral bending and axial rotation. The comparison of degree of freedom (DOF) and intradiscal pressure of two set models predicted that the levels adjacent to the implanted level were not significantly affected by the implanted XSTOP. There was a distinct restriction in the range of extension and intradiscal pressure at the implanted segment, and DOF decrease to 7483%. Furthermore, the largest von Mises stress showed on the interface between the spinous process and the implant at the position of extension. Respectively, the largest stress value is 333 MPa and 1356 MPa. In conclusion, the XSTOP can effectively restrict the DOF of extension and unloading disc pressure, without affect adjacent segment. Moreover, this study also provides theoretical and biomechanical analysis to support the clinical performance of the XSTOP and its further improvement of the device design.
2014 Vol. 33 (6): 729-736 [
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276
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737
Research on a Novel Sodium AlginateDexamethasone Composite Coating with MultiAldehyde Groups Applied to Extracoporeal Circuits#br#
GAO Wen Qing
1
LI Tong
1*
YU Mei Li
2
HU Xiao Min
1
DUAN Da Wei
1
DOI: 10.3969/j.issn.0258-8021.2014.06.014
The aim of this work is to prepare a novel composite coating of sodium alginate and dexamethasone. By optimizing the coating mode and conditions, the properties of stability, anticoagulation and controlled release were evaluated. Polyethyleneimine (PEI) was coated on PVC pipelines surface pretreated with acidification, dexamethasone sodium phosphate (DSP) was coated on PEIcoated pipelines (PP) with ionic bond, DSP coated pipelines were created (Group PPD). Pipelines coated OSADXM composite were created by ionic bond (Group PPI) or covalent bond (Group PPC). The control group (Group C) was set as well. The optimum coating condition was obtained by the orthogonal test. By evaluating the properties of different coated pipelines including anticoagulation, platelet adhesion, protein adhesion and release in vitro, the optimum coating mode was determined. DSP can be bound to PVC surface in Group PPD, PPI and PPC. The optimum immobilization quantity of DSP on different groups are (333±075),(163±076),(206±068) μg/cm2. The platelet adhesion (109/L) of Group PPI and PPC (1388±189 and 1913±340) was significantly reduced than that of Group C (4138±320). The protein adhesion (mg/cm2) of Group PPI and PPC (HAS: 2986±1357 and 4667±320, HPF: 3499±352 and 4567±379) was significantly decreased than that of Group PPD (Has: 6873±426, HPF: 7254±790). The release property of Group PPC is superior to that of Group PPI. The coating of OSADXM composite exhibited improved hemocompatibility. Covalently bound DSP can be controlled released.
2014 Vol. 33 (6): 737-745 [
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396
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746
Biodegradation of Electrospun Poly (Llactic acidcoεcaprolactone)/Collagen Composite Vascular Grafts
WANG Tao
1
CHEN Jian Feng
2
ZHAO Jun
1*
WU Tong
2
MO Xiu Mei
2
MEI Jia Cai
1
DOI: 10.3969/j.issn.0258-8021.2014.06.015
To evaluate the biodegradation and biocompatibility of poly (Llactic acidcoεcaprolactone) (P(LLACL))/collagen graft, P (LLACL) collagen graft scaffolds were made through electrospinning. The prepared scaffolds were set as experimental group (n=40) and the commercial artificial vessel made
of ePTFE was set as control group (n=40). The scaffold samples were implanted in the left dorsal muscle of rabbits, while ePTFE graft materials were implanted in the opposite side. On day 10, 30, 90 and 180 after the implantation, the samples were harvested. The histological staining was applied to observe the degradation of the material and tissue reaction. The number of neutrophils, macrophages and lymphocytes were counted at the high magnification (400×) using the optical microscope. Under the microscope, slight tissue reaction was revealed in the area of P (LLACL)/collagen material. On day 90, the material broken was observed. Some connective fibrous tissue was revealed in the material, a capsulelike membrane was established over the area. During the process of degradation, most of the materials were absorbed within 180 days. The structure and distribution of the tissue cells was highly similar to that of the surrounding area, indicating that the remodeling of the embedded tissue was almost finished. The ePTFE materials were revealed still maintaining the structure encompassed in a thin layer of fibrous connective tissue. The result of cell count showed that the type and trend of cell reaction had no difference after the different stages of postoperation. However, the count of neutrophile granulocyte in experimental group was more than that in the control group on day 10 (2244±372 vs 1922±181 /025 mm2, P<005), while no difference of various types of cells was observed between the two groups post operation. The degeneration of P (LLACL)/collagen material was 90-180 days, which is a satisfying biological performance in the degradation and biocompatibility.
2014 Vol. 33 (6): 746-752 [
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534
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471
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753
Motor Imagery EEG Analysis of the Spinocerebellar Ataxia Patients
ZHANG Ting
1
WANG Yong Xuan
2
LIU Rong
1*
DOI: 10.3969/j.issn.0258-8021.2014.06.016
2014 Vol. 33 (6): 753-758 [
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475
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758
The Behavior Analysis of the Upper Limb Based on Laparoscopic Training
YE Sha Sha WANG Shu Yi
*
BI Dong Dong
DOI: 10.3969/j.issn.0258-8021.2014.06.017
2014 Vol. 33 (6): 758-763 [
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261
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764
Investigation and Evaluation on Method of Transparency Measurement of Tissue Engineered Cornea
TAO Meng
1
LI Wen Kang
1
LI Gang
2
LI Hong
1*
DOI: 10.3969/j.issn.0258-8021.2014.06.018
2014 Vol. 33 (6): 764-768 [
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431
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