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Sample records for added motor imagery

  1. Organizing motor imageries.

    Hanakawa, Takashi

    2016-03-01

    Over the last few decades, motor imagery has attracted the attention of researchers as a prototypical example of 'embodied cognition' and also as a basis for neuro-rehabilitation and brain-machine interfaces. The current definition of motor imagery is widely accepted, but it is important to note that various abilities rather than a single cognitive entity are dealt with under a single term. Here, motor imagery has been characterized based on four factors: (1) motor control, (2) explicitness, (3) sensory modalities, and (4) agency. Sorting out these factors characterizing motor imagery may explain some discrepancies and variability in the findings from previous studies and will help to optimize a study design in accordance with the purpose of each study in the future. PMID:26602980

  2. The functional alterations associated with motor imagery training: a comparison between motor execution and motor imagery of sequential finger tapping

    Zhang, Hang; Yao, Li; Long, Zhiying

    2011-03-01

    Motor imagery training, as an effective strategy, has been more and more applied to mental disorders rehabilitation and motor skill learning. Studies on the neural mechanism underlying motor imagery have suggested that such effectiveness may be related to the functional congruence between motor execution and motor imagery. However, as compared to the studies on motor imagery, the studies on motor imagery training are much fewer. The functional alterations associated with motor imagery training and the effectiveness of motor imagery training on motor performance improvement still needs further investigation. Using fMRI, we employed a sequential finger tapping paradigm to explore the functional alterations associated with motor imagery training in both motor execution and motor imagery task. We hypothesized through 14 consecutive days motor imagery training, the motor performance could be improved and the functional congruence between motor execution and motor imagery would be sustained form pre-training phase to post-training phase. Our results confirmed the effectiveness of motor imagery training in improving motor performance and demonstrated in both pre and post-training phases, motor imagery and motor execution consistently sustained the congruence in functional neuroanatomy, including SMA (supplementary motor cortex), PMA (premotor area); M1( primary motor cortex) and cerebellum. Moreover, for both execution and imagery tasks, a similar functional alteration was observed in fusiform through motor imagery training. These findings provided an insight into the effectiveness of motor imagery training and suggested its potential therapeutic value in motor rehabilitation.

  3. Cognitive constraints on motor imagery.

    Dahm, Stephan F; Rieger, Martina

    2016-03-01

    Executed bimanual movements are prepared slower when moving to symbolically different than when moving to symbolically same targets and when targets are mapped to target locations in a left/right fashion than when they are mapped in an inner/outer fashion [Weigelt et al. (Psychol Res 71:238-447, 2007)]. We investigated whether these cognitive bimanual coordination constraints are observable in motor imagery. Participants performed fast bimanual reaching movements from start to target buttons. Symbolic target similarity and mapping were manipulated. Participants performed four action conditions: one execution and three imagination conditions. In the latter they indicated starting, ending, or starting and ending of the movement. We measured movement preparation (RT), movement execution (MT) and the combined duration of movement preparation and execution (RTMT). In all action conditions RTs and MTs were longer in movements towards different targets than in movements towards same targets. Further, RTMTs were longer when targets were mapped to target locations in a left/right fashion than when they were mapped in an inner/outer fashion, again in all action conditions. RTMTs in imagination and execution were similar, apart from the imagination condition in which participants indicated the start and the end of the movement. Here MTs, but not RTs, were longer than in the execution condition. In conclusion, cognitive coordination constraints are present in the motor imagery of fast (motor imagery. PMID:25758054

  4. Motor imagery in unipolar major depression

    Djamila Bennabi

    2014-12-01

    Full Text Available Background: Motor imagery is a potential tool to investigate action representation, as it can provide insights into the processes of action planning and preparation. Recent studies suggest that depressed patients present specific impairment in mental rotation. The present study was designed to investigate the influence of unipolar depression on motor imagery ability.Methods: Fourteen right-handed patients meeting DSM-IV criteria for unipolar depression were compared to fourteen matched healthy controls. Imagery ability was accessed by the timing correspondence between executed and imagined movements during a pointing task, involving strong spatiotemporal constraints (speed/accuracy trade off paradigm.Results: Compared to controls, depressed patients showed marked motor slowing on both actual and imagined movements. Furthermore, we observed greater temporal discrepancies between actual and mental movements in depressed patients than in healthy controls. Lastly, depressed patients modulated, to some extent, mental movement durations according to the difficulty of the task, but this modulation was not as strong as that of healthy subjects.Conclusion: These results suggest that unipolar depression significantly affects the higher stages of action planning and point out a selective decline of motor prediction.

  5. Motor Imagery in Unipolar Major Depression

    Bennabi, Djamila; Monnin, Julie; Haffen, Emmanuel; Carvalho, Nicolas; Vandel, Pierre; Pozzo, Thierry; Papaxanthis, Charalambos

    2014-01-01

    Background: Motor imagery is a potential tool to investigate action representation, as it can provide insights into the processes of action planning and preparation. Recent studies suggest that depressed patients present specific impairment in mental rotation. The present study was designed to investigate the influence of unipolar depression on motor imagery ability. Methods: Fourteen right-handed patients meeting DSM-IV criteria for unipolar depression were compared to 14 matched healthy controls. Imagery ability was accessed by the timing correspondence between executed and imagined movements during a pointing task, involving strong spatiotemporal constraints (speed/accuracy trade-off paradigm). Results: Compared to controls, depressed patients showed marked motor slowing on both actual and imagined movements. Furthermore, we observed greater temporal discrepancies between actual and mental movements in depressed patients than in healthy controls. Lastly, depressed patients modulated, to some extent, mental movement durations according to the difficulty of the task, but this modulation was not as strong as that of healthy subjects. Conclusion: These results suggest that unipolar depression significantly affects the higher stages of action planning and point out a selective decline of motor prediction. PMID:25538580

  6. Classification of motor imagery performance in acute stroke

    Tangwiriyasakul, Chayanin; Mocioiu, V.; Putten, van M.J.A.M.; Rutten, W.L.C.

    2014-01-01

    Objective. Effective motor imagery performance, seen as strong suppression of the sensorimotor rhythm, is the key element in motor imagery therapy. Therefore, optimization of methods to classify whether the subject is performing the imagery task is a prerequisite. An optimal classification method sh

  7. Selective effect of physical fatigue on motor imagery accuracy.

    Franck Di Rienzo

    Full Text Available While the use of motor imagery (the mental representation of an action without overt execution during actual training sessions is usually recommended, experimental studies examining the effect of physical fatigue on subsequent motor imagery performance are sparse and yielded divergent findings. Here, we investigated whether physical fatigue occurring during an intense sport training session affected motor imagery ability. Twelve swimmers (nine males, mean age 15.5 years conducted a 45 min physically-fatiguing protocol where they swam from 70% to 100% of their maximal aerobic speed. We tested motor imagery ability immediately before and after fatigue state. Participants randomly imagined performing a swim turn using internal and external visual imagery. Self-reports ratings, imagery times and electrodermal responses, an index of alertness from the autonomic nervous system, were the dependent variables. Self-reports ratings indicated that participants did not encounter difficulty when performing motor imagery after fatigue. However, motor imagery times were significantly shortened during posttest compared to both pretest and actual turn times, thus indicating reduced timing accuracy. Looking at the selective effect of physical fatigue on external visual imagery did not reveal any difference before and after fatigue, whereas significantly shorter imagined times and electrodermal responses (respectively 15% and 48% decrease, p<0.001 were observed during the posttest for internal visual imagery. A significant correlation (r=0.64; p<0.05 was observed between motor imagery vividness (estimated through imagery questionnaire and autonomic responses during motor imagery after fatigue. These data support that unlike local muscle fatigue, physical fatigue occurring during intense sport training sessions is likely to affect motor imagery accuracy. These results might be explained by the updating of the internal representation of the motor sequence, due to

  8. Mental Representation and Motor Imagery Training

    Thomas eSchack

    2014-05-01

    Full Text Available Research in sports, dance and rehabilitation has shown that Basic Action Concepts (BACs are fundamental building blocks of mental action representations. BACs are based on chunked body postures related to common functions for realizing action goals. In this paper, we outline issues in research methodology and an experimental method, SDA-M (structural dimensional analysis of mental representation, to assess action-relevant representational structures that reflect the organization of BACs. The SDA-M reveals a strong relationship between cognitive representation and performance if complex actions are performed. We show how the SDA-M can improve motor imagery training and how it contributes to our understanding of coaching processes. The SDA-M capitalizes on the objective measurement of individual mental movement representations before training and the integration of these results into the motor imagery training. Such motor imagery training based on mental representations has been applied successfully in professional sports such as golf, volleyball, gymnastics, windsurfing, and recently in the rehabilitation of patients who have suffered a stroke.

  9. Mental representation and motor imagery training.

    Schack, Thomas; Essig, Kai; Frank, Cornelia; Koester, Dirk

    2014-01-01

    Research in sports, dance and rehabilitation has shown that basic action concepts (BACs) are fundamental building blocks of mental action representations. BACs are based on chunked body postures related to common functions for realizing action goals. In this paper, we outline issues in research methodology and an experimental method, the structural dimensional analysis of mental representation (SDA-M), to assess action-relevant representational structures that reflect the organization of BACs. The SDA-M reveals a strong relationship between cognitive representation and performance if complex actions are performed. We show how the SDA-M can improve motor imagery training and how it contributes to our understanding of coaching processes. The SDA-M capitalizes on the objective measurement of individual mental movement representations before training and the integration of these results into the motor imagery training. Such motor imagery training based on mental representations (MTMR) has been applied successfully in professional sports such as golf, volleyball, gymnastics, windsurfing, and recently in the rehabilitation of patients who have suffered a stroke. PMID:24904368

  10. Auditory and motor imagery modulate learning in music performance.

    Brown, Rachel M; Palmer, Caroline

    2013-01-01

    Skilled performers such as athletes or musicians can improve their performance by imagining the actions or sensory outcomes associated with their skill. Performers vary widely in their auditory and motor imagery abilities, and these individual differences influence sensorimotor learning. It is unknown whether imagery abilities influence both memory encoding and retrieval. We examined how auditory and motor imagery abilities influence musicians' encoding (during Learning, as they practiced novel melodies), and retrieval (during Recall of those melodies). Pianists learned melodies by listening without performing (auditory learning) or performing without sound (motor learning); following Learning, pianists performed the melodies from memory with auditory feedback (Recall). During either Learning (Experiment 1) or Recall (Experiment 2), pianists experienced either auditory interference, motor interference, or no interference. Pitch accuracy (percentage of correct pitches produced) and temporal regularity (variability of quarter-note interonset intervals) were measured at Recall. Independent tests measured auditory and motor imagery skills. Pianists' pitch accuracy was higher following auditory learning than following motor learning and lower in motor interference conditions (Experiments 1 and 2). Both auditory and motor imagery skills improved pitch accuracy overall. Auditory imagery skills modulated pitch accuracy encoding (Experiment 1): Higher auditory imagery skill corresponded to higher pitch accuracy following auditory learning with auditory or motor interference, and following motor learning with motor or no interference. These findings suggest that auditory imagery abilities decrease vulnerability to interference and compensate for missing auditory feedback at encoding. Auditory imagery skills also influenced temporal regularity at retrieval (Experiment 2): Higher auditory imagery skill predicted greater temporal regularity during Recall in the presence of

  11. Auditory and motor imagery modulate learning in music performance

    Brown, Rachel M.; Palmer, Caroline

    2013-01-01

    Skilled performers such as athletes or musicians can improve their performance by imagining the actions or sensory outcomes associated with their skill. Performers vary widely in their auditory and motor imagery abilities, and these individual differences influence sensorimotor learning. It is unknown whether imagery abilities influence both memory encoding and retrieval. We examined how auditory and motor imagery abilities influence musicians' encoding (during Learning, as they practiced novel melodies), and retrieval (during Recall of those melodies). Pianists learned melodies by listening without performing (auditory learning) or performing without sound (motor learning); following Learning, pianists performed the melodies from memory with auditory feedback (Recall). During either Learning (Experiment 1) or Recall (Experiment 2), pianists experienced either auditory interference, motor interference, or no interference. Pitch accuracy (percentage of correct pitches produced) and temporal regularity (variability of quarter-note interonset intervals) were measured at Recall. Independent tests measured auditory and motor imagery skills. Pianists' pitch accuracy was higher following auditory learning than following motor learning and lower in motor interference conditions (Experiments 1 and 2). Both auditory and motor imagery skills improved pitch accuracy overall. Auditory imagery skills modulated pitch accuracy encoding (Experiment 1): Higher auditory imagery skill corresponded to higher pitch accuracy following auditory learning with auditory or motor interference, and following motor learning with motor or no interference. These findings suggest that auditory imagery abilities decrease vulnerability to interference and compensate for missing auditory feedback at encoding. Auditory imagery skills also influenced temporal regularity at retrieval (Experiment 2): Higher auditory imagery skill predicted greater temporal regularity during Recall in the presence of

  12. 2012 Oconee County, Georgia ADS80 Imagery

    National Oceanic and Atmospheric Administration, Department of Commerce — All imagery was collected during the 2012 Spring flying season during leaf-off conditions for deciduous vegetation in the State of Georgia. The sun angle was at...

  13. Motor imagery of hand actions: Decoding the content of motor imagery from brain activity in frontal and parietal motor areas.

    Pilgramm, Sebastian; de Haas, Benjamin; Helm, Fabian; Zentgraf, Karen; Stark, Rudolf; Munzert, Jörn; Krüger, Britta

    2016-01-01

    How motor maps are organized while imagining actions is an intensely debated issue. It is particularly unclear whether motor imagery relies on action-specific representations in premotor and posterior parietal cortices. This study tackled this issue by attempting to decode the content of motor imagery from spatial patterns of Blood Oxygen Level Dependent (BOLD) signals recorded in the frontoparietal motor imagery network. During fMRI-scanning, 20 right-handed volunteers worked on three experimental conditions and one baseline condition. In the experimental conditions, they had to imagine three different types of right-hand actions: an aiming movement, an extension-flexion movement, and a squeezing movement. The identity of imagined actions was decoded from the spatial patterns of BOLD signals they evoked in premotor and posterior parietal cortices using multivoxel pattern analysis. Results showed that the content of motor imagery (i.e., the action type) could be decoded significantly above chance level from the spatial patterns of BOLD signals in both frontal (PMC, M1) and parietal areas (SPL, IPL, IPS). An exploratory searchlight analysis revealed significant clusters motor- and motor-associated cortices, as well as in visual cortices. Hence, the data provide evidence that patterns of activity within premotor and posterior parietal cortex vary systematically with the specific type of hand action being imagined. PMID:26452176

  14. Using Mental Imagery To Enhance Children's Motor Performance.

    Short, Sandra E.; Afremow, James; Overby, Lynnette

    2001-01-01

    Students' motor performance can be enhanced through the use of mental imagery. This article presents nine ways that physical education teachers and coaches can use mental imagery to accomplish various outcomes. These include imagery for: learning, performing, focusing, self-confidence, motivation, arousal, changing negatives into positives,…

  15. Auditory and motor imagery modulate learning in music performance

    Rachel M. Brown

    2013-07-01

    Full Text Available Skilled performers such as athletes or musicians can improve their performance by imagining the actions or sensory outcomes associated with their skill. Performers vary widely in their auditory and motor imagery abilities, and these individual differences influence sensorimotor learning. It is unknown whether imagery abilities influence both memory encoding and retrieval. We examined how auditory and motor imagery abilities influence musicians’ encoding (during Learning, as they practiced novel melodies, and retrieval (during Recall of those melodies. Pianists learned melodies by listening without performing (auditory learning or performing without sound (motor learning; following Learning, pianists performed the melodies from memory with auditory feedback (Recall. During either Learning (Experiment 1 or Recall (Experiment 2, pianists experienced either auditory interference, motor interference, or no interference. Pitch accuracy (percentage of correct pitches produced and temporal regularity (variability of quarter-note interonset intervals were measured at Recall. Independent tests measured auditory and motor imagery skills. Pianists’ pitch accuracy was higher following auditory learning than following motor learning and lower in motor interference conditions (Experiments 1 and 2. Both auditory and motor imagery skills improved pitch accuracy overall. Auditory imagery skills modulated pitch accuracy encoding (Experiment 1: Higher auditory imagery skill corresponded to higher pitch accuracy following auditory learning with auditory or motor interference, and following motor learning with motor or no interference. These findings suggest that auditory imagery abilities decrease vulnerability to interference and compensate for missing auditory feedback at encoding. Auditory imagery skills also influenced temporal regularity at retrieval (Experiment 2: Higher auditory imagery skill predicted greater temporal regularity during Recall in the

  16. Adding Insult to Imagery? Art Education and Censorship

    Sweeny, Robert W.

    2007-01-01

    The "Adding Insult to Imagery? Artistic Responses to Censorship and Mass-Media" exhibition opened in January 16, 2006, Kipp Gallery on the Indiana University of Pennsylvania campus. Eleven gallery-based works, 9 videos, and 10 web-based artworks comprised the show; each dealt with the relationship between censorship and mass mediated images. Many…

  17. Enhancing voluntary imitation through attention and motor imagery.

    Bek, Judith; Poliakoff, Ellen; Marshall, Hannah; Trueman, Sophie; Gowen, Emma

    2016-07-01

    Action observation activates brain areas involved in performing the same action and has been shown to increase motor learning, with potential implications for neurorehabilitation. Recent work indicates that the effects of action observation on movement can be increased by motor imagery or by directing attention to observed actions. In voluntary imitation, activation of the motor system during action observation is already increased. We therefore explored whether imitation could be further enhanced by imagery or attention. Healthy participants observed and then immediately imitated videos of human hand movement sequences, while movement kinematics were recorded. Two blocks of trials were completed, and after the first block participants were instructed to imagine performing the observed movement (Imagery group, N = 18) or attend closely to the characteristics of the movement (Attention group, N = 15), or received no further instructions (Control group, N = 17). Kinematics of the imitated movements were modulated by instructions, with both Imagery and Attention groups being closer in duration, peak velocity and amplitude to the observed model compared with controls. These findings show that both attention and motor imagery can increase the accuracy of imitation and have implications for motor learning and rehabilitation. Future work is required to understand the mechanisms by which these two strategies influence imitation accuracy. PMID:26892882

  18. Motor imagery as a tool for motor skill training in children

    A. Doussoulin; L. Rehbein

    2011-01-01

    The present study aimed at checking the effectiveness of motor imagery on children's motor training. A total of 64 students aged 9 to 10 years, enrolled in three different 4th grade classes, participated in the study. Subjects in the modeling group were asked to view the video recording of an expert performing the task; those in the physical practice group were trained through the actual execution of the task; and subjects in the imagery group, were trained based solely on motor imagery. The ...

  19. The correlation between motor impairments and event-related desynchronization during motor imagery in ALS patients

    Kasahara Takashi

    2012-06-01

    Full Text Available Abstract Background The event-related desynchronization (ERD in EEG is known to appear during motor imagery, and is thought to reflect cortical processing for motor preparation. The aim of this study is to examine the modulation of ERD with motor impairment in ALS patients. ERD during hand motor imagery was obtained from 8 ALS patients with a variety of motor impairments. ERD was also obtained from age-matched 11 healthy control subjects with the same motor task. The magnitude and frequency of ERD were compared between groups for characterization of ALS specific changes. Results The ERD of ALS patients were significantly smaller than those of control subjects. Bulbar function and ERD were negatively correlated in ALS patients. Motor function of the upper extremities did was uncorrelated with ERD. Conclusions ALS patients with worsened bulbar scales may show smaller ERD. Motor function of the upper extremities did was uncorrelated with ERD.

  20. Investigating effects of different artefact types on motor imagery BCI

    Frølich, Laura; Winkler, Irene; Muller, Klaus-Robert;

    2015-01-01

    . We investigate different artefacts' effects on motor-imagery based BCI relying on Common Spatial Patterns (CSP). Data stem from an 80-subject BCI study. We use the recently developed classifier IC_MARC to classify independent components of EEG data into neural and five classes of artefacts. We find...

  1. Rehearsal strategies during motor-sequence learning in old age : Execution vs motor imagery

    Stoter, Arjan J. R.; Scherder, Erik J. A.; Kamsma, Yvo P. T.; Mulder, Theo

    2008-01-01

    Motor imagery and action-based rehearsal were compared during motor sequence-learning by young adults (M = 25 yr., SD = 3) and aged adults (M = 63 yr., SD = 7). General accuracy of aged adults was lower than that of young adults (F-1,F-28 = 7.37, p = .01) even though working-memory capacity was equi

  2. Best practice for motor imagery: a systematic literature review on motor imagery training elements in five different disciplines

    Scheidhauer Anne

    2011-06-01

    Full Text Available Abstract Background The literature suggests a beneficial effect of motor imagery (MI if combined with physical practice, but detailed descriptions of MI training session (MITS elements and temporal parameters are lacking. The aim of this review was to identify the characteristics of a successful MITS and compare these for different disciplines, MI session types, task focus, age, gender and MI modification during intervention. Methods An extended systematic literature search using 24 databases was performed for five disciplines: Education, Medicine, Music, Psychology and Sports. References that described an MI intervention that focused on motor skills, performance or strength improvement were included. Information describing 17 MITS elements was extracted based on the PETTLEP (physical, environment, timing, task, learning, emotion, perspective approach. Seven elements describing the MITS temporal parameters were calculated: study duration, intervention duration, MITS duration, total MITS count, MITS per week, MI trials per MITS and total MI training time. Results Both independent reviewers found 96% congruity, which was tested on a random sample of 20% of all references. After selection, 133 studies reporting 141 MI interventions were included. The locations of the MITS and position of the participants during MI were task-specific. Participants received acoustic detailed MI instructions, which were mostly standardised and live. During MI practice, participants kept their eyes closed. MI training was performed from an internal perspective with a kinaesthetic mode. Changes in MI content, duration and dosage were reported in 31 MI interventions. Familiarisation sessions before the start of the MI intervention were mentioned in 17 reports. MI interventions focused with decreasing relevance on motor-, cognitive- and strength-focused tasks. Average study intervention lasted 34 days, with participants practicing MI on average three times per week for 17

  3. Local Temporal Correlation Common Spatial Patterns for Single Trial EEG Classification during Motor Imagery

    Rui Zhang

    2013-01-01

    Full Text Available Common spatial pattern (CSP is one of the most popular and effective feature extraction methods for motor imagery-based brain-computer interface (BCI, but the inherent drawback of CSP is that the estimation of the covariance matrices is sensitive to noise. In this work, local temporal correlation (LTC information was introduced to further improve the covariance matrices estimation (LTCCSP. Compared to the Euclidean distance used in a previous CSP variant named local temporal CSP (LTCSP, the correlation may be a more reasonable metric to measure the similarity of activated spatial patterns existing in motor imagery period. Numerical comparisons among CSP, LTCSP, and LTCCSP were quantitatively conducted on the simulated datasets by adding outliers to Dataset IVa of BCI Competition III and Dataset IIa of BCI Competition IV, respectively. Results showed that LTCCSP achieves the highest average classification accuracies in all the outliers occurrence frequencies. The application of the three methods to the EEG dataset recorded in our laboratory also demonstrated that LTCCSP achieves the highest average accuracy. The above results consistently indicate that LTCCSP would be a promising method for practical motor imagery BCI application.

  4. Phantom limb perception interferes with motor imagery after unilateral upper-limb amputation

    Yuanyuan Lyu; Xiaoli Guo; Robin Bekrater-Bodmann; Herta Flor; Shanbao Tong

    2016-01-01

    A potential contributor to impaired motor imagery in amputees is an alteration of the body schema as a result of the presence of a phantom limb. However, the nature of the relationship between motor imagery and phantom experiences remains unknown. In this study, the influence of phantom limb perception on motor imagery was investigated using a hand mental rotation task by means of behavioral and electrophysiological measures. Compared with healthy controls, significantly prolonged response ti...

  5. Comparison of Sensory-motor Rhythm and Movement Related Cortical Potential during Ballistic and Repetitive Motor Imagery

    XU Ren; JIANG Ning; MRACHACZ-KERSTING Natalie; DREMSTRUP Kim; FARINA Dario

    2014-01-01

    In this study, we compared two types of EEG modalities, sensory-motor rhythms (SMR) and movement related cortical potentials (MRCP), on four healthy subjects performing ballistic or repetitive movement imagination. The EEG waveform morphology across subjects was similar for MRCPs, whereas there was not a clear pattern for SMRs. The rank-sum test showed a significant difference between the amplitude of baseline and that of the MRCP as early as 2 s prior to imagery onset, for both types of motor imageries, indicating strong discriminative power of MRCPs for predicting movement onset. For SMR, this type of discriminative power was relatively weak and highly subject-specific. On the other hand, the SMR landscape under the two movement imagery types was distinctive, holding a potential for discriminating the two movement imagery types. These preliminary results presented different characteristics of SMR and MRCP under different motor imageries, providing valuable information regarding the design and implementation of motor imagery based on BCI system.

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

    Masahito Mihara

    Full Text Available 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.

  7. Motor imagery in REM sleep is increased by transcranial direct current stimulation of the left motor cortex (C3).

    Speth, Jana; Speth, Clemens

    2016-06-01

    This study investigates if anodal transcranial direct current stimulation (tDCS) of areas above the motor cortex (C3) influences the quantity and quality of spontaneous motor imagery experienced in REM sleep. A randomized triple-blinded design was used, combining neurophysiological techniques with a tool of quantitative mentation report analysis developed from cognitive linguistics and generative grammar. The results indicate that more motor imagery, and more athletic motor imagery, is induced by anodal tDCS in comparison to cathodal and sham tDCS. This insight may have implications beyond basic consciousness research. Motor imagery in REM sleep has been hypothesized to serve the rehearsal of motor movements, which benefits later motor performance. Electrophysiological manipulations of motor imagery in REM sleep could in the long run be used for rehabilitative tDCS protocols benefitting temporarily immobile clinical patients, especially those who cannot perform specific motor imagery tasks - such as dementia patients, infants with developmental and motor disorders, and coma patients. PMID:27079954

  8. Parallel Alterations of Functional Connectivity during Execution and Imagination after Motor Imagery Learning

    Zhang, Hang; Xu, Lele; Zhang, Rushao; Hui, Mingqi; Long, Zhiying; Zhao, Xiaojie; Yao, Li

    2012-01-01

    Background Neural substrates underlying motor learning have been widely investigated with neuroimaging technologies. Investigations have illustrated the critical regions of motor learning and further revealed parallel alterations of functional activation during imagination and execution after learning. However, little is known about the functional connectivity associated with motor learning, especially motor imagery learning, although benefits from functional connectivity analysis attract mor...

  9. Motor imagery training in hemiplegic cerebral palsy: a potentially useful therapeutic tool for rehabilitation

    Steenbergen, B.; Craje, Céline; Nilsen, D.M.; Gordon, A.M.

    2009-01-01

    Converging evidence indicates that motor deficits in cerebral palsy (CP) are related not only to problems with execution, but also to impaired motor planning. Current rehabilitation mainly focuses on alleviating compromised motor execution. Motor imagery is a promising method of training the more 'c

  10. Functional equivalence or behavioural matching? A critical reflection on 15 years of research using the PETTLEP model of motor imagery

    Wakefield, Caroline; Smith, Dave; Moran, Aidan P.; Holmes, Paul

    2012-01-01

    Motor imagery, or the mental rehearsal of actions in the absence of physical movement, is an increasingly popular construct in fields such as neuroscience, cognitive psychology and sport psychology. Unfortunately, few models of motor imagery have been postulated to date. Nevertheless, based on the hypothesis of functional equivalence between imagery, perception and motor execution, Holmes and Collins in 2001 developed the PETTLEP model of motor imagery in an effort to provide evidence-based g...

  11. Efficient resting-state EEG network facilitates motor imagery performance

    Zhang, Rui; Yao, Dezhong; Valdés-Sosa, Pedro A.; Li, Fali; Li, Peiyang; Zhang, Tao; Ma, Teng; Li, Yongjie; Xu, Peng

    2015-12-01

    Objective. Motor imagery-based brain-computer interface (MI-BCI) systems hold promise in motor function rehabilitation and assistance for motor function impaired people. But the ability to operate an MI-BCI varies across subjects, which becomes a substantial problem for practical BCI applications beyond the laboratory. Approach. Several previous studies have demonstrated that individual MI-BCI performance is related to the resting state of brain. In this study, we further investigate offline MI-BCI performance variations through the perspective of resting-state electroencephalography (EEG) network. Main results. Spatial topologies and statistical measures of the network have close relationships with MI classification accuracy. Specifically, mean functional connectivity, node degrees, edge strengths, clustering coefficient, local efficiency and global efficiency are positively correlated with MI classification accuracy, whereas the characteristic path length is negatively correlated with MI classification accuracy. The above results indicate that an efficient background EEG network may facilitate MI-BCI performance. Finally, a multiple linear regression model was adopted to predict subjects’ MI classification accuracy based on the efficiency measures of the resting-state EEG network, resulting in a reliable prediction. Significance. This study reveals the network mechanisms of the MI-BCI and may help to find new strategies for improving MI-BCI performance.

  12. New evidence of corticospinal network modulation induced by motor imagery.

    Grosprêtre, Sidney; Lebon, Florent; Papaxanthis, Charalambos; Martin, Alain

    2016-03-01

    Motor imagery (MI) is the mental simulation of movement, without the corresponding muscle contraction. Whereas the activation of cortical motor areas during MI is established, the involvement of spinal structures is still under debate. We used original and complementary techniques to probe the influence of MI on spinal structures. Amplitude of motor-evoked potentials (MEPs), cervico-medullary-evoked potentials (CMEPs), and Hoffmann (H)-reflexes of the flexor carpi radialis (FCR) muscle and of the triceps surae muscles was measured in young, healthy subjects at rest and during MI. Participants were asked to imagine maximal voluntary contraction of the wrist and ankle, while the targeted limb was fixed (static condition). We confirmed previous studies with an increase of FCR MEPs during MI compared with rest. Interestingly, CMEPs, but not H-reflexes, also increased during MI, revealing a possible activation of subcortical structures. Then, to investigate the effect of MI on the spinal network, we used two techniques: 1) passive lengthening of the targeted muscle via an isokinetic dynamometer and 2) conditioning of H-reflexes with stimulation of the antagonistic nerve. Both techniques activate spinal inhibitory presynaptic circuitry, reducing the H-reflex amplitude at rest. In contrast, no reduction of H-reflex amplitude was observed during MI. These findings suggest that MI has modulatory effects on the spinal neuronal network. Specifically, the activation of low-threshold spinal structures during specific conditions (lengthening and H-reflex conditioning) highlights the possible generation of subliminal cortical output during MI. PMID:26719089

  13. Development of a Wearable Motor-Imagery-Based Brain-Computer Interface.

    Lin, Bor-Shing; Pan, Jeng-Shyang; Chu, Tso-Yao; Lin, Bor-Shyh

    2016-03-01

    A motor-imagery-based brain-computer interface (BCI) is a translator that converts the motor intention of the brain into a control command to control external machines without muscles. Numerous motor-imagery-based BCIs have been successfully proposed in previous studies. However, several electroencephalogram (EEG) channels are typically required for providing sufficient information to maintain a specific accuracy and bit rate, and the bulk volume of these EEG machines is also inconvenient. A wearable motor imagery-based BCI system was proposed and implemented in this study. A wearable mechanical design with novel active comb-shaped dry electrodes was developed to measure EEG signals without conductive gels at hair sites, which is easy and convenient for users wearing the EEG machine. In addition, a wireless EEG acquisition module was also designed to measure EEG signals, which provides a user with more freedom of motion. The proposed wearable motor-imagery-based BCI system was validated using an electrical specifications test and a hand motor imagery experiment. Experimental results showed that the proposed wearable motor-imagery-based BCI system provides favorable signal quality for measuring EEG signals and detecting motor imagery. PMID:26748791

  14. Oscillatory entrainment of the motor cortical network during motor imagery is modulated by the feedback modality.

    Vukelić, Mathias; Gharabaghi, Alireza

    2015-05-01

    Neurofeedback of self-regulated brain activity in circumscribed cortical regions is used as a novel strategy to facilitate functional restoration following stroke. Basic knowledge about its impact on motor system oscillations and functional connectivity is however scarce. Specifically, a direct comparison between different feedback modalities and their neural signatures is missing. We assessed a neurofeedback training intervention of modulating β-activity in circumscribed sensorimotor regions by kinesthetic motor imagery (MI). Right-handed healthy participants received two different feedback modalities contingent to their MI-associated brain activity in a cross-over design: (I) visual feedback with a brain-computer interface (BCI) and (II) proprioceptive feedback with a brain-robot interface (BRI) orthosis attached to the right hand. High-density electroencephalography was used to examine the reactivity of the cortical motor system during the training session of each task by studying both local oscillatory power entrainment and distributed functional connectivity. Both feedback modalities activated a distributed functional connectivity network of coherent oscillations. A significantly higher skill and lower variability of self-controlled sensorimotor β-band modulation could, however, be achieved in the BRI condition. This gain in controlling regional motor oscillations was accompanied by functional coupling of remote β-band and θ-band activity in bilateral fronto-central regions and left parieto-occipital regions, respectively. The functional coupling of coherent θ-band oscillations correlated moreover with the skill of regional β-modulation thus revealing a motor learning related network. Our findings indicate that proprioceptive feedback is more suitable than visual feedback to entrain the motor network architecture during the interplay between motor imagery and feedback processing thus resulting in better volitional control of regional brain activity. PMID

  15. MOTOR IMAGERY AND TENNIS SERVE PERFORMANCE: THE EXTERNAL FOCUS EFFICACY

    Aymeric Guillot

    2013-06-01

    Full Text Available There is now ample evidence that motor imagery (MI contributes to enhance motor performance. Previous research also demonstrated that directing athletes' attention to the effects of their movements on the environment is more effective than focusing on the action per se. The present study aimed therefore at evaluating whether adopting an external focus during MI contributes to enhance tennis serve performance. Twelve high-level young tennis players were included in a test-retest procedure. The effects of regular training were first evaluated. Then, players were subjected to a MI intervention during which they mentally focused on ball trajectory and specifically visualized the space above the net where the serve can be successfully hit. Serve performance was evaluated during both a validated serve test and a real match. The main results showed a significant increase in accuracy and velocity during the ecological serve test after MI practice, as well as a significant improvement in successful first serves and won points during the match. Present data therefore confirmed the efficacy of MI in combination of physical practice to improve tennis serve performance, and further provided evidence that it is feasible to adopt external attentional focus during MI. Practical applications are discussed

  16. Multiple roles of motor imagery during action observation

    Stefan Vogt

    2013-11-01

    Full Text Available Over the last 20 years, the topics of action observation (AO and motor imagery (MI have been largely studied in isolation from each other, despite the early integrative account by Jeannerod (1994, 2001. Recent neuroimaging studies demonstrate enhanced cortical activity when AO and MI are performed concurrently ('AO+MI', compared to either AO or MI performed in isolation. These results indicate the potentially beneficial effects of AO+MI, and they also demonstrate that the underlying neurocognitive processes are partly shared. We separately review the evidence for MI and AO as forms of motor simulation, and present two quantitative literature analyses that indeed indicate rather little overlap between the two bodies of research. We then propose a spectrum of concurrent AO+MI states, from congruent AO+MI where the contents of AO and MI widely overlap, over coordinative AO+MI, where observed and imagined action are different but can be coordinated with each other, to cases of conflicting AO+MI. We believe that an integrative account of AO and MI is theoretically attractive, that it should generate novel experimental approaches, and that it can also stimulate a wide range of applications in sport, occupational therapy, and neurorehabilitation.

  17. Motor imagery as a tool to enhance the didactics in physical education and artistic gymnastic.

    Gaetano Raiola

    2013-09-01

    Full Text Available The motor imagery is a cognitive process of mental simulation of an action in absence of physical movement. During the motor imagery the cerebral areas of the pre-motor cortex, the same which a muscular contraction would put in action, are activated. There are two methods of motor imagery: In first person - In thirdperson. The biological basis on which the motor imagery theory is founded, is formed by mirror neurons. The mirror neurons are a particular class of visual-motor neurons which permit to learn and to optimize a motor gesture without executing it. The mirror neurons are the basis for learning and understanding of motor events intentions. The artistic gymnastics is a sport of precision and the movements are complex,then it use the abilities closed skills. The artistic gymnastics uses the model of closed-loop control.According to the recruitment of energy, artistic gymnastics is a sport mainly alactacid anaerobic/lactate. Starting from these scientific assumptions the aim of this study wants to evaluate the effects and the potential benefits of motor imagery in order to contribute to the strengthening of young athletes performances in the artistic gym. Used in training in the race. - See more at: http://www.jhse.ua.es/jhse/article/view/492#sthash.8uA7TkfL.dpuf

  18. Using motor imagery to study the neural substrates of dynamic balance

    Murielle Ursulla Ferraye; Bettina Debû; Lieke Heil; Mark Carpenter; Bastiaan Roelof Bloem; Ivan Toni

    2014-01-01

    This study examines the cerebral structures involved in dynamic balance using a motor imagery (MI) protocol. We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined swaying on a balance board along the sagittal plane to point a laser at target pairs of different sizes (small, large). We used a matched visual imagery (VI) control task and recorded imagery durations during scanning. MI and VI durations were differentially influenced by the sway accuracy ...

  19. Context-aware adaptive spelling in motor imagery BCI

    Perdikis, S.; Leeb, R.; Millán, J. d. R.

    2016-06-01

    Objective. This work presents a first motor imagery-based, adaptive brain–computer interface (BCI) speller, which is able to exploit application-derived context for improved, simultaneous classifier adaptation and spelling. Online spelling experiments with ten able-bodied users evaluate the ability of our scheme, first, to alleviate non-stationarity of brain signals for restoring the subject’s performances, second, to guide naive users into BCI control avoiding initial offline BCI calibration and, third, to outperform regular unsupervised adaptation. Approach. Our co-adaptive framework combines the BrainTree speller with smooth-batch linear discriminant analysis adaptation. The latter enjoys contextual assistance through BrainTree’s language model to improve online expectation-maximization maximum-likelihood estimation. Main results. Our results verify the possibility to restore single-sample classification and BCI command accuracy, as well as spelling speed for expert users. Most importantly, context-aware adaptation performs significantly better than its unsupervised equivalent and similar to the supervised one. Although no significant differences are found with respect to the state-of-the-art PMean approach, the proposed algorithm is shown to be advantageous for 30% of the users. Significance. We demonstrate the possibility to circumvent supervised BCI recalibration, saving time without compromising the adaptation quality. On the other hand, we show that this type of classifier adaptation is not as efficient for BCI training purposes.

  20. Electroencephalographic Motor Imagery Brain Connectivity Analysis for BCI: A Review.

    Hamedi, Mahyar; Salleh, Sh-Hussain; Noor, Alias Mohd

    2016-06-01

    Recent research has reached a consensus on the feasibility of motor imagery brain-computer interface (MI-BCI) for different applications, especially in stroke rehabilitation. Most MI-BCI systems rely on temporal, spectral, and spatial features of single channels to distinguish different MI patterns. However, no successful communication has been established for a completely locked-in subject. To provide more useful and informative features, it has been recommended to take into account the relationships among electroencephalographic (EEG) sensor/source signals in the form of brain connectivity as an efficient tool of neuroscience. In this review, we briefly report the challenges and limitations of conventional MI-BCIs. Brain connectivity analysis, particularly functional and effective, has been described as one of the most promising approaches for improving MI-BCI performance. An extensive literature on EEG-based MI brain connectivity analysis of healthy subjects is reviewed. We subsequently discuss the brain connectomes during left and right hand, feet, and tongue MI movements. Moreover, key components involved in brain connectivity analysis that considerably affect the results are explained. Finally, possible technical shortcomings that may have influenced the results in previous research are addressed and suggestions are provided. PMID:27137671

  1. Classifications of Motor Imagery Tasks in Brain Computer Interface Using Linear Discriminant Analysis

    Roxana Aldea

    2014-07-01

    Full Text Available In this paper, we address a method for motor imagery feature extraction for brain computer interface (BCI. The wavelet coefficients were used to extract the features from the motor imagery EEG and the linear discriminant analysis was utilized to classify the pattern of left or right hand imagery movement and rest. The performance of the proposed method was evaluated using EEG data recorded by us, with 8 g.tec active electrodes by means of g.MOBIlab+ module. The maximum accuracy of classification is 91%.

  2. Improvement in precision grip force control with self-modulation of primary motor cortex during motor imagery

    Maria Laura eBlefari

    2015-02-01

    Full Text Available Motor imagery (MI has shown effectiveness in enhancing motor performance. This may be due to the common neural mechanisms underlying MI and motor execution (ME. The main region of the ME network, the primary motor cortex (M1, has been consistently linked to motor performance. However, the activation of M1 during motor imagery is controversial, which may account for inconsistent rehabilitation therapy outcomes using MI. Here, we examined the relationship between contralateral M1 (cM1 activation during MI and changes in sensorimotor performance. To aid cM1 activity modulation during MI, we used real-time fMRI neurofeedback-guided MI based on cM1 hand area blood oxygen level dependent (BOLD signal in healthy subjects, performing kinesthetic MI of pinching. We used multiple regression analysis to examine the correlation between cM1 BOLD signal and changes in motor performance during an isometric pinching task of those subjects who were able to activate cM1 during motor imagery. Activities in premotor and parietal regions were used as covariates. We found that cM1 activity was positively correlated to improvements in accuracy as well as overall performance improvements, whereas other regions in the sensorimotor network were not. The association between cM1 activation during MI with performance changes indicates that subjects with stronger cM1 activation during MI may benefit more from MI training, with implications towards targeted neurotherapy.

  3. Differences in Motor Imagery Time when Predicting Task Duration in Alpine Skiers and Equestrian Riders

    Louis, Magali; Collet, Christian; Champely, Stephane; Guillot, Aymeric

    2012-01-01

    Athletes' ability to use motor imagery (MI) to predict the speed at which they could perform a motor sequence has received little attention. In this study, 21 alpine skiers and 16 equestrian riders performed MI based on a prediction of actual performance time (a) after the course inspection, (b) before the start, and (c) after the actual…

  4. Mental imagery of speech: linking motor and perceptual systems through internal simulation and estimation

    Xing Tian

    2012-11-01

    Full Text Available The neural basis of mental imagery has been investigated by localizing the underlying neural networks, mostly in motor and perceptual systems, separately. However, how modality-specific representations are top-down induced and how the action and perception systems interact in the context of mental imagery is not well understood. Imagined speech production (‘articulation imagery’, which induces the kinesthetic feeling of articulator movement and its auditory consequences, provides a new angle because of the concurrent involvement of motor and perceptual systems. On the basis of previous findings in mental imagery of speech, we argue for the following regarding the induction mechanisms of mental imagery and the interaction between motor and perceptual systems: (1 Two distinct top-down mechanisms, memory retrieval and motor simulation, exist to induce estimation in perceptual systems. (2 Motor simulation is sufficient to internally induce the representation of perceptual changes that would be caused by actual movement (perceptual associations; however, this simulation process only has modulatory effects on the perception of external stimuli, which critically depends on context and task demands. Considering the proposed simulation-estimation processes as common mechanisms for interaction between motor and perceptual systems, we outline how mental imagery (of speech relates to perception and production, and how these hypothesized mechanisms might underpin certain neural disorders.

  5. Short time sports exercise boosts motor imagery patterns: Implications of mental practice in rehabilitation programs

    Selina Christin Wriessnegger

    2014-06-01

    Full Text Available Motor imagery (MI is a commonly used paradigm for the study of motor learning or cognitive aspects of action control. The rationale for using MI training to promote the relearning of motor function arises from research on the functional correlates that MI shares with the execution of physical movements. While most of the previous studies investigating MI were based on simple movements in the present study a more attractive mental practice was used to investigate cortical activation during MI. We measured cerebral responses with functional magnetic resonance imaging (fMRI in twenty three healthy volunteers as they imagined playing soccer or tennis before and after a short physical sports exercise. Our results demonstrated that only 10 minutes of training are enough to boost motor imagery patterns in motor related brain regions including premotor cortex and supplementary motor area (SMA but also fronto-parietal and subcortical structures. This supports previous findings that motor imagery has beneficial effects especially in combination with motor execution when used in motor rehabilitation or motor learning processes. We conclude that sports MI combined with an interactive game environment could be a promising additional tool in future rehabilitation programs aiming to improve upper or lower limb functions or support neuroplasticity.

  6. Effect of biased feedback on motor imagery learning in BCI-teleoperation system

    Maryam eAlimardani

    2014-04-01

    Full Text Available Feedback design is an important issue in motor imagery BCI systems. Regardless, to date it has not been reported how feedback presentation can optimize co-adaptation between a human brain and such systems. This paper assesses the effect of realistic visual feedback on users’ BC performance and motor imagery skills. We previously developed a tele-operation system for a pair of humanlike robotic hands and showed that BCI control of such hands along with first-person perspective visual feedback of movements can arouse a sense of embodiment in the operators. In the first stage of this study, we found that the intensity of this ownership illusion was associated with feedback presentation and subjects’ performance during BCI motion control. In the second stage, we probed the effect of positive and negative feedback bias on subjects’ BCI performance and motor imagery skills. Although the subject specific classifier, which was set up at the beginning of experiment, detected no significant change in the subjects’ online performance, evaluation of brain activity patterns revealed that subjects’ self-regulation of motor imagery features improved due to a positive bias of feedback and a possible occurrence of ownership illusion. Our findings suggest that in general training protocols for BCIs, manipulation of feedback can play an important role in the optimization of subjects’ motor imagery skills.

  7. The Importance of Visual Feedback Design in BCIs; from Embodiment to Motor Imagery Learning.

    Alimardani, Maryam; Nishio, Shuichi; Ishiguro, Hiroshi

    2016-01-01

    Brain computer interfaces (BCIs) have been developed and implemented in many areas as a new communication channel between the human brain and external devices. Despite their rapid growth and broad popularity, the inaccurate performance and cost of user-training are yet the main issues that prevent their application out of the research and clinical environment. We previously introduced a BCI system for the control of a very humanlike android that could raise a sense of embodiment and agency in the operators only by imagining a movement (motor imagery) and watching the robot perform it. Also using the same setup, we further discovered that the positive bias of subjects' performance both increased their sensation of embodiment and improved their motor imagery skills in a short period. In this work, we studied the shared mechanism between the experience of embodiment and motor imagery. We compared the trend of motor imagery learning when two groups of subjects BCI-operated different looking robots, a very humanlike android's hands and a pair of metallic gripper. Although our experiments did not show a significant change of learning between the two groups immediately during one session, the android group revealed better motor imagery skills in the follow up session when both groups repeated the task using the non-humanlike gripper. This result shows that motor imagery skills learnt during the BCI-operation of humanlike hands are more robust to time and visual feedback changes. We discuss the role of embodiment and mirror neuron system in such outcome and propose the application of androids for efficient BCI training. PMID:27598310

  8. Classification of Motor Imagery EEG Signals with Support Vector Machines and Particle Swarm Optimization.

    Ma, Yuliang; Ding, Xiaohui; She, Qingshan; Luo, Zhizeng; Potter, Thomas; Zhang, Yingchun

    2016-01-01

    Support vector machines are powerful tools used to solve the small sample and nonlinear classification problems, but their ultimate classification performance depends heavily upon the selection of appropriate kernel and penalty parameters. In this study, we propose using a particle swarm optimization algorithm to optimize the selection of both the kernel and penalty parameters in order to improve the classification performance of support vector machines. The performance of the optimized classifier was evaluated with motor imagery EEG signals in terms of both classification and prediction. Results show that the optimized classifier can significantly improve the classification accuracy of motor imagery EEG signals. PMID:27313656

  9. Classification of Motor Imagery EEG Signals with Support Vector Machines and Particle Swarm Optimization

    Ma, Yuliang; Ding, Xiaohui; She, Qingshan; Luo, Zhizeng; Potter, Thomas; Zhang, Yingchun

    2016-01-01

    Support vector machines are powerful tools used to solve the small sample and nonlinear classification problems, but their ultimate classification performance depends heavily upon the selection of appropriate kernel and penalty parameters. In this study, we propose using a particle swarm optimization algorithm to optimize the selection of both the kernel and penalty parameters in order to improve the classification performance of support vector machines. The performance of the optimized classifier was evaluated with motor imagery EEG signals in terms of both classification and prediction. Results show that the optimized classifier can significantly improve the classification accuracy of motor imagery EEG signals. PMID:27313656

  10. An adaptive filter bank for motor imagery based Brain Computer Interface.

    Thomas, Kavitha P; Guan, Cuntai; Tong, Lau Chiew; Prasad, Vinod A

    2008-01-01

    Brain Computer Interface (BCI) provides an alternative communication and control method for people with severe motor disabilities. Motor imagery patterns are widely used in Electroencephalogram (EEG) based BCIs. These motor imagery activities are associated with variation in alpha and beta band power of EEG signals called Event Related Desynchronization/synchronization (ERD/ERS). The dominant frequency bands are subject-specific and therefore performance of motor imagery based BCIs are sensitive to both temporal filtering and spatial filtering. As the optimum filter is strongly subject-dependent, we propose a method that selects the subject-specific discriminative frequency components using time-frequency plots of Fisher ratio of two-class motor imagery patterns. We also propose a low complexity adaptive Finite Impulse Response (FIR) filter bank system based on coefficient decimation technique which can realize the subject-specific bandpass filters adaptively depending on the information of Fisher ratio map. Features are extracted only from the selected frequency components. The proposed adaptive filter bank based system offers average classification accuracy of about 90%, which is slightly better than the existing fixed filter bank system. PMID:19162856

  11. Facilitation of Corticospinal Excitability According to Motor Imagery and Mirror Therapy in Healthy Subjects and Stroke Patients

    Kang, Youn Joo; Ku, Jeonghun; Kim, Hyun Jung; Park, Hae Kyung

    2011-01-01

    Objective To delineate the changes in corticospinal excitability when individuals are asked to exercise their hand using observation, motor imagery, voluntary exercise, and exercise with a mirror. Method The participants consisted of 30 healthy subjects and 30 stroke patients. In healthy subjects, the amplitudes and latencies of motor evoked potential (MEP) were obtained using seven conditions: (A) rest; (B) imagery; (C) observation and imagery of the hand activity of other individuals; (D) o...

  12. Effects of motor imagery combined with functional electrical stimulation on upper limb motor function of patients with acute ischemic stroke

    Shou-feng LIU

    2015-03-01

    Full Text Available Objective To explore the effects of motor imagery (MI combined with the third generation functional electrical stimulation (FES on upper limb motor function in acute ischemic stroke patients with hemiplegia.  Methods Forty acute ischemic stroke patients, within 48 h of onset, were randomly divided into FES group (N = 20 and combination group (FES combined with motor imagery, N = 20. All patients received basic routine rehabilitation training, for example, good limb positioning, accepting braces, balance training and training in the activities of daily living (ADL. FES group received the third generation FES therapy and the combination group also received motor imagery for 2 weeks. All of the patients were assessed with Fugl-Meyer Assessment (FMA, Action Research Arm Test (ARAT and active range of motion (AROM of wrist dorsiflexion before and after 2 weeks of treatment.  Results After 2 weeks of treatment, the 2 groups had significantly higher FMA score, ARAT score and AROM of wrist dorsiflexion than that in pre-treatment (P = 0.000, for all. Besides, the FMA score (t = - 2.528, P = 0.016, ARAT score (t = - 2.562, P = 0.014 and AROM of wrist dorsiflexion (t = - 2.469, P = 0.018 in the combination group were significantly higher than that in the FES group. There were interactions of treatment methods with observation time points (P < 0.05, for all.  Conclusions Motor imagery combined with the third generation FES can effectively promote the recovery of upper limb motor function and motion range of wrist dorsiflexion in patients with acute ischemic stroke. DOI: 10.3969/j.issn.1672-6731.2015.03.008

  13. Motor imagery and EEG-based control of spelling devices and neuroprostheses.

    Neuper, Christa; Müller-Putz, Gernot R; Scherer, Reinhold; Pfurtscheller, Gert

    2006-01-01

    A brain-computer interface (BCI) transforms signals originating from the human brain into commands that can control devices or applications. With this, a BCI provides a new non-muscular communication channel, which can be used to assist patients who have highly compromised motor functions. The Graz-BCI uses motor imagery and associated oscillatory EEG signals from the sensorimotor cortex for device control. As a result of research in the past 15 years, the classification of ERD/ERS patterns in single EEG trials during motor execution and motor imagery forms the basis of this sensorimotor-rhythm controlled BCI. The major frequency bands of cortical oscillations considered here are the 8-13 and 15-30 Hz bands. This chapter describes the basic methods used in Graz-BCI research and outlines possible clinical applications. PMID:17071244

  14. Motor imagery training promotes motor learning in adolescents with cerebral palsy: comparison between left and right hemiparesis.

    Cabral-Sequeira, Audrey Sartori; Coelho, Daniel Boari; Teixeira, Luis Augusto

    2016-06-01

    This experiment was designed to evaluate the effects of pure motor imagery training (MIT) and its combination with physical practice on learning an aiming task with the more affected arm in adolescents suffering from cerebral palsy. Effect of MIT was evaluated as a function of side of hemiparesis. The experiment was accomplished by 11- to 16-year-old participants (M = 13.58 years), who suffered left (n = 16) or right (n = 15) mild hemiparesis. They were exposed to pure MIT (day 1) followed by physical practice (day 2) on an aiming task demanding movement accuracy and speed. Posttraining movement kinematics of the group receiving MIT were compared with movement kinematics of the control group after receiving recreational activities (day 1) and physical practice (day 2). Kinematic analysis showed that MIT led to decreased movement time and straighter hand displacements to the target. Performance achievements from MIT were increased with further physical practice, leading to enhanced effects on motor learning. Retention evaluation indicated that performance improvement from pure MIT and its combination with physical practice were stable over time. Performance achievements were equivalent between adolescents with either right or left hemiparesis, suggesting similar capacity between these groups to achieve performance improvement from pure imagery training and from its association with physical practice. Our results suggest that motor imagery training is a procedure potentially useful to increase motor learning achievements in individuals suffering from cerebral palsy. PMID:26821314

  15. Using motor imagery to study the neural substrates of dynamic balance

    Ferraye, M.U.; Debû, B.H.G.; Heil, L.; Carpenter, M.; Bloem, B.R.; Toni, I.

    2014-01-01

    This study examines the cerebral structures involved in dynamic balance using a motor imagery (MI) protocol. We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined swaying on a balance board along the sagittal plane to point a laser at target pairs of differ

  16. Phantom limb perception interferes with motor imagery after unilateral upper-limb amputation.

    Lyu, Yuanyuan; Guo, Xiaoli; Bekrater-Bodmann, Robin; Flor, Herta; Tong, Shanbao

    2016-01-01

    A potential contributor to impaired motor imagery in amputees is an alteration of the body schema as a result of the presence of a phantom limb. However, the nature of the relationship between motor imagery and phantom experiences remains unknown. In this study, the influence of phantom limb perception on motor imagery was investigated using a hand mental rotation task by means of behavioral and electrophysiological measures. Compared with healthy controls, significantly prolonged response time for both the intact and missing hand were observed specifically in amputees who perceived a phantom limb during the task but not in amputees without phantom limb perception. Event-related desynchronization of EEG in the beta band (beta-ERD) in central and parietal areas showed an angular disparity specifically in amputees with phantom limb perception, with its source localized in the right inferior parietal lobule. The response time as well as the beta-ERD values were significantly positively correlated with phantom vividness. Our results suggest that phantom limb perception during the task is an important interferential factor for motor imagery after amputation and the interference might be related to a change of the body representation resulting from an unnatural posture of the phantom limb. PMID:26879749

  17. Clinical evaluation of BrainTree, a motor imagery hybrid BCI speller

    Perdikis, S.; Leeb, R.; Williamson, J.; Ramsay, A.; Tavella, M.; Desideri, L.; Hoogerwerf, E.-J.; Al-Khodairy, A.; Murray-Smith, R.; Millán, J. d. R.

    2014-06-01

    Objective. While brain-computer interfaces (BCIs) for communication have reached considerable technical maturity, there is still a great need for state-of-the-art evaluation by the end-users outside laboratory environments. To achieve this primary objective, it is necessary to augment a BCI with a series of components that allow end-users to type text effectively. Approach. This work presents the clinical evaluation of a motor imagery (MI) BCI text-speller, called BrainTree, by six severely disabled end-users and ten able-bodied users. Additionally, we define a generic model of code-based BCI applications, which serves as an analytical tool for evaluation and design. Main results. We show that all users achieved remarkable usability and efficiency outcomes in spelling. Furthermore, our model-based analysis highlights the added value of human-computer interaction techniques and hybrid BCI error-handling mechanisms, and reveals the effects of BCI performances on usability and efficiency in code-based applications. Significance. This study demonstrates the usability potential of code-based MI spellers, with BrainTree being the first to be evaluated by a substantial number of end-users, establishing them as a viable, competitive alternative to other popular BCI spellers. Another major outcome of our model-based analysis is the derivation of a 80% minimum command accuracy requirement for successful code-based application control, revising upwards previous estimates attempted in the literature.

  18. The Movement Imagery Questionnaire-Revised, Second Edition (MIQ-RS Is a Reliable and Valid Tool for Evaluating Motor Imagery in Stroke Populations

    Andrew J. Butler

    2012-01-01

    Full Text Available Mental imagery can improve motor performance in stroke populations when combined with physical therapy. Valid and reliable instruments to evaluate the imagery ability of stroke survivors are needed to maximize the benefits of mental imagery therapy. The purposes of this study were to: examine and compare the test-retest intra-rate reliability of the Movement Imagery Questionnaire-Revised, Second Edition (MIQ-RS in stroke survivors and able-bodied controls, examine internal consistency of the visual and kinesthetic items of the MIQ-RS, determine if the MIQ-RS includes both the visual and kinesthetic dimensions of mental imagery, correlate impairment and motor imagery scores, and investigate the criterion validity of the MIQ-RS in stroke survivors by comparing the results to the KVIQ-10. Test-retest analysis indicated good levels of reliability (ICC range: .83–.99 and internal consistency (Cronbach α: .95–.98 of the visual and kinesthetic subscales in both groups. The two-factor structure of the MIQ-RS was supported by factor analysis, with the visual and kinesthetic components accounting for 88.6% and 83.4% of the total variance in the able-bodied and stroke groups, respectively. The MIQ-RS is a valid and reliable instrument in the stroke population examined and able-bodied populations and therefore useful as an outcome measure for motor imagery ability.

  19. Using motor imagery to study the neural substrates of dynamic balance.

    Murielle Ursulla Ferraye

    Full Text Available This study examines the cerebral structures involved in dynamic balance using a motor imagery (MI protocol. We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined swaying on a balance board along the sagittal plane to point a laser at target pairs of different sizes (small, large. We used a matched visual imagery (VI control task and recorded imagery durations during scanning. MI and VI durations were differentially influenced by the sway accuracy requirement, indicating that MI of balance is sensitive to the increased motor control necessary to point at a smaller target. Compared to VI, MI of dynamic balance recruited additional cortical and subcortical portions of the motor system, including frontal cortex, basal ganglia, cerebellum and mesencephalic locomotor region, the latter showing increased effective connectivity with the supplementary motor area. The regions involved in MI of dynamic balance were spatially distinct but contiguous to those involved in MI of gait (Bakker et al., 2008; Snijders et al., 2011; Crémers et al., 2012, in a pattern consistent with existing somatotopic maps of the trunk (for balance and legs (for gait. These findings validate a novel, quantitative approach for studying the neural control of balance in humans. This approach extends previous reports on MI of static stance (Jahn et al., 2004, 2008, and opens the way for studying gait and balance impairments in patients with neurodegenerative disorders.

  20. Prediction of motor imagery based brain computer interface performance using a reaction time test.

    Darvishi, Sam; Abbott, Derek; Baumert, Mathias

    2015-08-01

    Brain computer interfaces (BCIs) enable human brains to interact directly with machines. Motor imagery based BCI (MI-BCI) encodes the motor intentions of human agents and provides feedback accordingly. However, 15-30% of people are not able to perform vivid motor imagery. To save time and monetary resources, a number of predictors have been proposed to screen for users with low BCI aptitude. While the proposed predictors provide some level of correlation with MI-BCI performance, simple, objective and accurate predictors are currently not available. Thus, in this study we have examined the utility of a simple reaction time (SRT) test for predicting MI-BCI performance. We enrolled 10 subjects and measured their motor imagery performance with either visual or proprioceptive feedback. Their reaction time was also measured using a SRT test. The results show a significant negative correlation (r ≈ -0.67) between SRT and MI-BCI performance. Therefore SRT may be used as a simple and reliable predictor of MI-BCI performance. PMID:26736893

  1. The thermal state of the ad motor at the reduce rotor speed

    Коцур, Михайло Ігорович

    2013-01-01

    Changing in the conditions of cooling in recursive short-time modes in wide range of rotor speed occurs under the exploitation of the crane electric drive based on AD motors. The aim of this article is to estimate the thermal state of the AD motor at low rotor speed, as well as comparative analysis execution of the AD motor ampacity calculated by the average loss of heat and equivalent thermal circuit (ETC) methods. Electrothermal model to consider peculiarities of electromagnetic energy tran...

  2. Real-Time Brain-Computer Interface System Based on Motor Imagery

    Tie-Jun Liu; Ping Yang; Xu-Yong Peng; Yu Huang; De-Zhong Yao

    2009-01-01

    A brain-computer interface (BCI) real-time system based on motor imagery translates the user's motor intention into a real-time control signal for peripheral equipments.A key problem to be solved for practical applications is real-time data collection and processing.In this paper,a real-time BCI system is implemented on computer with electroencephalogram amplifier.In our implementation,the on-line voting method is adopted for feedback control strategy,and the voting results are used to control the cursor horizontal movement.Three subjects take part in the experiment.The results indicate that the best accuracy is 90%.

  3. Effect of Motor Imagery on the F-Wave Parameters in Hemiparetic Stroke Survivors

    Naseri, Mahshid; Petramfar, Peyman; Ashraf, Alireza

    2015-01-01

    Objective To assess the effect of motor imagery, as a rehabilitation method in stroke, on F-wave parameters that undergo changes during upper motor neuron involvement. Methods Twenty-one fully conscious hemiparetic stroke survivors with a completely plegic hand (power 0/5) and a minimum interval of 72 hours since stroke were recruited into this study. The mean F-wave latency, amplitude, and persistence in the median and ulnar nerves were measured in both the affected and non-affected sides at...

  4. 4-CLASS MOTOR IMAGERY CLASSIFICATION FOR POST STROKE REHABILITATION USING BRAIN-COMPUTER INTERFACE

    Aarathi Kumar*, Nisha. P. V

    2016-01-01

    Brain-Computer Interface (BCI) is a mechanism that helps in the control/communication of one’s environment through the brain signals obtained directly from the brain via an EEG signal acquisition unit. A BCI incorporating Motor Imagery for post-stroke rehabilitation of upper limbs and knee in fully disabled patients is designed. It helps in restoring some of the activities of the daily living. It aids post-stroke sufferers to carry out functionalities like movement of right an...

  5. BRAIN-COMPUTER-INTERFACE – SUPPORTED MOTOR IMAGERY TRAININTG FOR PATIENTS WITH HEMIPARESIS

    O. A. Mokienko

    2013-01-01

    Full Text Available The aim of study was to assess the feasibility of motor imagery supported brain-computer interface in patients with hemiparesis. 13 patients with central paresis of the hand and 15 healthy volunteers were learning to control EEG-based interface with feedback. No differences on interface control quality were found between patients and healthy subjects. The trainings were accompanied by the desynchronization of sensorimotor rhythm. In patients with cortical damage the source of EEG-activity was dislocated.

  6. Localization of Brain Electrical Activity Sources and Hemodynamic Activity Foci during Motor Imagery

    Frolov, A. A.; Húsek, Dušan; Mokienko, O.; Bobrov, P.; Chernikova, L.; Konovalov, R.

    2014-01-01

    Roč. 40, č. 3 (2014), s. 273-283. ISSN 0362-1197 Grant ostatní: GA MŠk(CZ) ED1.1.00/02.0070; GA MŠk(CZ) EE.2.3.20.0073 Institutional support: RVO:67985807 Keywords : brain computer interface * independent component analysis * EEG pattern classification * motor imagery * inverse EEG problem Subject RIV: IN - Informatics, Computer Science

  7. Cognitive alterations in motor imagery process after left hemispheric ischemic stroke.

    Jing Yan

    Full Text Available BACKGROUND: Motor imagery training is a promising rehabilitation strategy for stroke patients. However, few studies had focused on the neural mechanisms in time course of its cognitive process. This study investigated the cognitive alterations after left hemispheric ischemic stroke during motor imagery task. METHODOLOGY/PRINCIPAL FINDINGS: Eleven patients with ischemic stroke in left hemisphere and eleven age-matched control subjects participated in mental rotation task (MRT of hand pictures. Behavior performance, event-related potential (ERP and event-related (desynchronization (ERD/ERS in beta band were analyzed to investigate the cortical activation. We found that: (1 The response time increased with orientation angles in both groups, called "angle effect", however, stoke patients' responses were impaired with significantly longer response time and lower accuracy rate; (2 In early visual perceptual cognitive process, stroke patients showed hypo-activations in frontal and central brain areas in aspects of both P200 and ERD; (3 During mental rotation process, P300 amplitude in control subjects decreased while angle increased, called "amplitude modulation effect", which was not observed in stroke patients. Spatially, patients showed significant lateralization of P300 with activation only in contralesional (right parietal cortex while control subjects showed P300 in both parietal lobes. Stroke patients also showed an overall cortical hypo-activation of ERD during this sub-stage; (4 In the response sub-stage, control subjects showed higher ERD values with more activated cortical areas particularly in the right hemisphere while angle increased, named "angle effect", which was not observed in stroke patients. In addition, stroke patients showed significant lower ERD for affected hand (right response than that for unaffected hand. CONCLUSIONS/SIGNIFICANCE: Cortical activation was altered differently in each cognitive sub-stage of motor imagery after

  8. Subject-oriented training for motor imagery brain-computer interfaces

    Perdikis, Serafeim; Leeb, Robert; Millán, José del R.

    2014-01-01

    Successful operation of motor imagery (MI)-based brain-computer interfaces (BCI) requires mutual adaptation between the human subject and the BCI. Traditional training methods, as well as more recent ones based on co-adaptation, have mainly focused on the machine-learning aspects of BCI training. This work presents a novel co-adaptive training protocol shifting the focus on subject-related performances and the optimal accommodation of the interactions between the two learning agents of the BC...

  9. Implementation of Motor Imagery during Specific Aerobic Training Session in Young Tennis Players

    Aymeric Guillot; Franck Di Rienzo; Vincent Pialoux; Germain Simon; Sarah Skinner; Isabelle Rogowski

    2015-01-01

    The aim of this study was to investigate the effects of implementing motor imagery (MI) during specific tennis high intensity intermittent training (HIIT) sessions on groundstroke performance in young elite tennis players. Stroke accuracy and ball velocity of forehand and backhand drives were evaluated in ten young tennis players, immediately before and after having randomly performed two HIIT sessions. One session included MI exercises during the recovery phases, while the other included ver...

  10. An Algorithm for Idle-State Detection in Motor-Imagery-Based Brain-Computer Interface

    Yijun Wang; Dan Zhang; Xiaorong Gao; Bo Hong; Shangkai Gao

    2007-01-01

    For a robust brain-computer interface (BCI) system based on motor imagery (MI), it should be able to tell when the subject is not concentrating on MI tasks (the “idle state”) so that real MI tasks could be extracted accurately. Moreover, because of the diversity of idle state, detecting idle state without training samples is as important as classifying MI tasks. In this paper, we propose an algorithm for solving this ...

  11. A neural network-based optimal spatial filter design method for motor imagery classification.

    Yuksel, Ayhan; Olmez, Tamer

    2015-01-01

    In this study, a novel spatial filter design method is introduced. Spatial filtering is an important processing step for feature extraction in motor imagery-based brain-computer interfaces. This paper introduces a new motor imagery signal classification method combined with spatial filter optimization. We simultaneously train the spatial filter and the classifier using a neural network approach. The proposed spatial filter network (SFN) is composed of two layers: a spatial filtering layer and a classifier layer. These two layers are linked to each other with non-linear mapping functions. The proposed method addresses two shortcomings of the common spatial patterns (CSP) algorithm. First, CSP aims to maximize the between-classes variance while ignoring the minimization of within-classes variances. Consequently, the features obtained using the CSP method may have large within-classes variances. Second, the maximizing optimization function of CSP increases the classification accuracy indirectly because an independent classifier is used after the CSP method. With SFN, we aimed to maximize the between-classes variance while minimizing within-classes variances and simultaneously optimizing the spatial filter and the classifier. To classify motor imagery EEG signals, we modified the well-known feed-forward structure and derived forward and backward equations that correspond to the proposed structure. We tested our algorithm on simple toy data. Then, we compared the SFN with conventional CSP and its multi-class version, called one-versus-rest CSP, on two data sets from BCI competition III. The evaluation results demonstrate that SFN is a good alternative for classifying motor imagery EEG signals with increased classification accuracy. PMID:25933101

  12. A Wearable Channel Selection-Based Brain-Computer Interface for Motor Imagery Detection.

    Lo, Chi-Chun; Chien, Tsung-Yi; Chen, Yu-Chun; Tsai, Shang-Ho; Fang, Wai-Chi; Lin, Bor-Shyh

    2016-01-01

    Motor imagery-based brain-computer interface (BCI) is a communication interface between an external machine and the brain. Many kinds of spatial filters are used in BCIs to enhance the electroencephalography (EEG) features related to motor imagery. The approach of channel selection, developed to reserve meaningful EEG channels, is also an important technique for the development of BCIs. However, current BCI systems require a conventional EEG machine and EEG electrodes with conductive gel to acquire multi-channel EEG signals and then transmit these EEG signals to the back-end computer to perform the approach of channel selection. This reduces the convenience of use in daily life and increases the limitations of BCI applications. In order to improve the above issues, a novel wearable channel selection-based brain-computer interface is proposed. Here, retractable comb-shaped active dry electrodes are designed to measure the EEG signals on a hairy site, without conductive gel. By the design of analog CAR spatial filters and the firmware of EEG acquisition module, the function of spatial filters could be performed without any calculation, and channel selection could be performed in the front-end device to improve the practicability of detecting motor imagery in the wearable EEG device directly or in commercial mobile phones or tablets, which may have relatively low system specifications. Finally, the performance of the proposed BCI is investigated, and the experimental results show that the proposed system is a good wearable BCI system prototype. PMID:26861347

  13. Flying across Galaxy Clusters with Google Earth: additional imagery from SDSS co-added data

    Galaxy clusters are spectacular. We provide a Google Earth compatible imagery for the deep co-added images from the Sloan Digital Sky Survey and make it a tool for examing galaxy clusters. Google Earth (in sky mode) provides a highly interactive environment for visualizing the sky. By encoding the galaxy cluster information into a kml/kmz file, one can use Google Earth as a tool for examining galaxy clusters and fly across them freely. However, the resolution of the images provided by Google Earth is not very high. This is partially because the major imagery google earth used is from Sloan Digital Sky Survey (SDSS) (SDSS collaboration 2000) and the resolutions have been reduced to speed up the web transferring. To have higher resolution images, you need to add your own images in a way that Google Earth can understand. The SDSS co-added data are the co-addition of ∼100 scans of images from SDSS stripe 82 (Annis et al. 2010). It provides the deepest images based on SDSS and reach as deep as about redshift 1.0. Based on the co-added images, we created color images in a way as described by Lupton et al. (2004) and convert the color images to Google Earth compatible images using wcs2kml (Brewer et al. 2007). The images are stored at a public server at Fermi National Accelerator Laboratory and can be accessed by the public. To view those images in Google Earth, you need to download a kmz file, which contains the links to the color images, and then open the kmz file with your Google Earth. To meet different needs for resolutions, we provide three kmz files corresponding to low, medium and high resolution images. We recommend the high resolution one as long as you have a broadband Internet connection, though you should choose to download any of them, depending on your own needs and Internet speed. After you open the downloaded kmz file with Google Earth (in sky mode), it takes about 5 minutes (depending on your Internet connection and the resolution of images you want

  14. Robot-Aided Upper-Limb Rehabilitation Based on Motor Imagery EEG

    Baoguo Xu

    2011-09-01

    Full Text Available Stroke is a leading cause of disability worldwide. In this paper, a novel robot‐assisted rehabilitation system based on motor imagery electroencephalography (EEG is developed for regular training of neurological rehabilitation for upper limb stroke patients. Firstly, three‐dimensional animation was used to guide the patient image the upper limb movement and EEG signals were acquired by EEG amplifier. Secondly, eigenvectors were extracted by harmonic wavelet transform (HWT and linear discriminant analysis (LDA classifier was utilized to classify the pattern of the left and right upper limb motor imagery EEG signals. Finally, PC triggered the upper limb rehabilitation robot to perform motor therapy and gave the virtual feedback. Using this robot‐assisted upper limb rehabilitation system, the patientʹs EEG of upper limb movement imagination is translated to control rehabilitation robot directly. Consequently, the proposed rehabilitation system can fully explore the patientʹs motivation and attention and directly facilitate upper limb post‐stroke rehabilitation therapy. Experimental results on unimpaired participants were presented to demonstrate the feasibility of the rehabilitation system. Combining robot‐assisted training with motor imagery‐ based BCI will make future rehabilitation therapy more effective. Clinical testing is still required for further proving this assumption.

  15. Modulation of mu rhythm desynchronization during motor imagery by transcranial direct current stimulation

    Kimura Akio

    2010-06-01

    Full Text Available Abstract Background The mu event-related desynchronization (ERD is supposed to reflect motor preparation and appear during motor imagery. The aim of this study is to examine the modulation of ERD with transcranial direct current stimulation (tDCS. Methods Six healthy subjects were asked to imagine their right hand grasping something after receiving a visual cue. Electroencephalograms (EEGs were recorded near the left M1. ERD of the mu rhythm (mu ERD by right hand motor imagery was measured. tDCS (10 min, 1 mA was used to modulate the cortical excitability of M1. Anodal, cathodal, and sham tDCS were tested in each subject with a randomized sequence on different days. Each condition was separated from the preceding one by more than 1 week in the same subject. Before and after tDCS, mu ERD was assessed. The motor thresholds (MT of the left M1 were also measured with transcranial magnetic stimulation. Results Mu ERD significantly increased after anodal stimulation, whereas it significantly decreased after cathodal stimulation. There was a significant correlation between mu ERD and MT. Conclusions Opposing effects on mu ERD based on the orientation of the stimulation suggest that mu ERD is affected by cortical excitability.

  16. Brisk heart rate and EEG changes during execution and withholding of cue-paced foot motor imagery

    Robert J Barry

    2013-07-01

    Full Text Available Cue-paced motor imagery is a frequently used mental strategy to realize a Brain-Computer Interace (BCI. Recently it has been reported that 2 motor imagery tasks can be separated with a high accuracy within the first second after cue presentation onset. To investigate this phenomenon in detail we studied the dynamics of motor cortex beta oscillations in EEG and the changes in heart rate (HR during visual cue-paced foot imagery using a go (execution of imagery versus nogo (withholding of imagery paradigm in 16 healthy subjects. Both execution and withholding of motor imagery resulted in a brisk centrally localized beta ERD with a maximum at ~ 400 ms and a concomitant HR deceleration. We found that response patterns within the first second after stimulation differed between conditions. The ERD was significantly larger in go as compared to nogo. In contrast the HR deceleration was somewhat smaller and followed by an acceleration in go as compared to nogo. These findings suggest that the early beta ERD reflects visually induced preparatory activity in motor cortex networks. Both the early beta ERD and HR deceleration are the result of automatic operating processes that are likely part of the orienting reflex. Of interest, however, is that the preparatory cortical activity is strengthened and the HR modulated already within the first second after stimulation during the execution of motor imagery. The subtraction of the HR time course of the nogo from the go condition revealed a slight HR acceleration in the first seconds most likely due to the increased mental effort associated with the imagery process.

  17. Characterizing skill acquisition through motor imagery with no prior physical practice.

    Kraeutner, Sarah N; MacKenzie, Laura A; Westwood, David A; Boe, Shaun G

    2016-02-01

    Motor learning depends upon plasticity in neural networks involved in the planning and execution of movement. Physical practice (PP) is the primary means of motor learning, but it can be augmented with nonphysical forms of practice including motor imagery (MI)-the mental rehearsal of movement. It is unknown if MI alone, without prior PP of a movement, can produce robust learning. Here the authors used an implicit sequence learning task to explore motor learning via MI alone or PP. Participants underwent implicit sequence learning training via MI (n = 31) or PP (n = 33). Posttraining reaction time was faster for implicit versus random sequences for both the MI group (M = 583 ± 84 ms; 632 ± 86 ms, d = 0.59) and PP group (M = 532 ± 73 ms; 589 ± 70 ms, d = 0.80), demonstrating that MI without PP facilitated skill acquisition. Relative to MI alone, PP led to reduced reaction time for both random (d = 0.65) and implicit sequences (d = 0.55) consistent with a nonspecific motor benefit favoring PP over MI. These results have broad implication for theories of MI and support the use of MI as a form of practice to acquire implicit motor skills. (PsycINFO Database Record PMID:26389615

  18. Effect of instructive visual stimuli on neurofeedback training for motor imagery-based brain-computer interface.

    Kondo, Toshiyuki; Saeki, Midori; Hayashi, Yoshikatsu; Nakayashiki, Kosei; Takata, Yohei

    2015-10-01

    Event-related desynchronization (ERD) of the electroencephalogram (EEG) from the motor cortex is associated with execution, observation, and mental imagery of motor tasks. Generation of ERD by motor imagery (MI) has been widely used for brain-computer interfaces (BCIs) linked to neuroprosthetics and other motor assistance devices. Control of MI-based BCIs can be acquired by neurofeedback training to reliably induce MI-associated ERD. To develop more effective training conditions, we investigated the effect of static and dynamic visual representations of target movements (a picture of forearms or a video clip of hand grasping movements) during the BCI neurofeedback training. After 4 consecutive training days, the group that performed MI while viewing the video showed significant improvement in generating MI-associated ERD compared with the group that viewed the static image. This result suggests that passively observing the target movement during MI would improve the associated mental imagery and enhance MI-based BCIs skills. PMID:25467185

  19. Motor imagery modality in expert dancers: an investigation of hip and pelvis kinematics in demi-plié and sauté.

    Coker, Elizabeth; McIsaac, Tara L; Nilsen, Dawn

    2015-06-01

    Elite dancers often engage in mental practice during training, but little is known about the effects of discrete, repetitive motor imagery on dance movement performance. This study compared the effects of two motor imagery modalities, third-person visual imagery and kinesthetic imagery, on hip and pelvis kinematics during two technical dance movements, plié and sauté. Twenty-four female dancers (mean age: 26.04; mean years of training: 19.63) were randomly assigned to a type of imagery practice: visual imagery (VI), kinesthetic imagery (KI), or a mental arithmetic task control condition (MAT). No statistically significant effects of imagery group or task type were found for external hip rotation, sagittal pelvic excursion, or a ratio relating hip to pelvic movement, suggesting that imagery practice did not affect either temporal or kinematic characteristics of the plié or sauté. PMID:26045397

  20. A treatment of EEG data by underdetermined blind source separation for motor imagery classification

    Koldovský, Zbyněk; Phan, A. H.; Tichavský, Petr; Cichocki, A.

    Bucharest: EURASIP, 2012, s. 1484-1488. ISBN 978-1-4673-1068-0. ISSN 2076-1465. [20th European Signal Processing Conference (EUSIPCO 2012). Bukurešť (RO), 27.08.2012-31.08.2012] Grant ostatní: GA ČR(CZ) GAP103/11/1947 Institutional support: RVO:67985556 Keywords : electroencephalogram * brain-computer Interface * underdetermined blind source separation Subject RIV: FH - Neurology http://library.utia.cas.cz/separaty/2012/SI/tichavsky-a treatment of eeg data by underdetermined blind source separation for motor imagery classification.pdf

  1. Functional Magnetic Resonance Imaging Neurofeedback-guided Motor Imagery Training and Motor Training for Parkinson’s Disease: Randomized Trial

    Subramanian, Leena; Morris, Monica Busse; Brosnan, Meadhbh; Turner, Duncan L.; Morris, Huw R.; Linden, David E. J.

    2016-01-01

    Objective: Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback (NF) uses feedback of the patient’s own brain activity to self-regulate brain networks which in turn could lead to a change in behavior and clinical symptoms. The objective was to determine the effect of NF and motor training (MOT) alone on motor and non-motor functions in Parkinson’s Disease (PD) in a 10-week small Phase I randomized controlled trial. Methods: Thirty patients with Parkinson’s disease (PD; Hoehn and Yahr I-III) and no significant comorbidity took part in the trial with random allocation to two groups. Group 1 (NF: 15 patients) received rt-fMRI-NF with MOT. Group 2 (MOT: 15 patients) received MOT alone. The primary outcome measure was the Movement Disorder Society—Unified PD Rating Scale-Motor scale (MDS-UPDRS-MS), administered pre- and post-intervention “off-medication”. The secondary outcome measures were the “on-medication” MDS-UPDRS, the PD Questionnaire-39, and quantitative motor assessments after 4 and 10 weeks. Results: Patients in the NF group were able to upregulate activity in the supplementary motor area (SMA) by using motor imagery. They improved by an average of 4.5 points on the MDS-UPDRS-MS in the “off-medication” state (95% confidence interval: −2.5 to −6.6), whereas the MOT group improved only by 1.9 points (95% confidence interval +3.2 to −6.8). The improvement in the intervention group meets the minimal clinically important difference which is also on par with other non-invasive therapies such as repetitive Transcranial Magnetic Stimulation (rTMS). However, the improvement did not differ significantly between the groups. No adverse events were reported in either group. Interpretation: This Phase I study suggests that NF combined with MOT is safe and improves motor symptoms immediately after treatment, but larger trials are needed to explore its superiority over active control conditions. PMID:27375451

  2. Bipolar electrode selection for a motor imagery based brain computer interface

    Lou, Bin; Hong, Bo; Gao, Xiaorong; Gao, Shangkai

    2008-09-01

    A motor imagery based brain-computer interface (BCI) provides a non-muscular communication channel that enables people with paralysis to control external devices using their motor imagination. Reducing the number of electrodes is critical to improving the portability and practicability of the BCI system. A novel method is proposed to reduce the number of electrodes to a total of four by finding the optimal positions of two bipolar electrodes. Independent component analysis (ICA) is applied to find the source components of mu and alpha rhythms, and optimal electrodes are chosen by comparing the projection weights of sources on each channel. The results of eight subjects demonstrate the better classification performance of the optimal layout compared with traditional layouts, and the stability of this optimal layout over a one week interval was further verified.

  3. Motor imagery and its effect on complex regional pain syndrome: an integrative review

    Nélio Silva de Souza

    2015-12-01

    Full Text Available The motor imagery (MI has been proposed as a treatment in the complex regional pain syndrome type 1 (CRPS-1, since it seems to promote a brain reorganization effect on sensory- motor areas of pain perception. The aim of this paper is to investigate, through an integrative critical review, the influence of MI on the CRPS-1, correlating their evidence to clinical practice. Research in PEDro, Medline, Bireme and Google Scholar databases was conducted. Nine randomized controlled trials (level 2, 1 non-controlled clinical study (level 3, 1 case study (level 4, 1 systematic review (level 1, 2 review articles and 1 comment (level 5 were found. We can conclude that MI has shown effect in reducing pain and functionality that remains after 6 months of treatment. However, the difference between the MI strategies for CRPS-1 is unknown as well as the intensity of mental stress influences the painful response or effect of MI or other peripheral neuropathies.

  4. Testing the Self-Similarity Exponent to Feature Extraction in Motor Imagery Based Brain Computer Interface Systems

    Rodríguez-Bermúdez, Germán; Sánchez-Granero, Miguel Ángel; García-Laencina, Pedro J.; Fernández-Martínez, Manuel; Serna, José; Roca-Dorda, Joaquín

    2015-12-01

    A Brain Computer Interface (BCI) system is a tool not requiring any muscle action to transmit information. Acquisition, preprocessing, feature extraction (FE), and classification of electroencephalograph (EEG) signals constitute the main steps of a motor imagery BCI. Among them, FE becomes crucial for BCI, since the underlying EEG knowledge must be properly extracted into a feature vector. Linear approaches have been widely applied to FE in BCI, whereas nonlinear tools are not so common in literature. Thus, the main goal of this paper is to check whether some Hurst exponent and fractal dimension based estimators become valid indicators to FE in motor imagery BCI. The final results obtained were not optimal as expected, which may be due to the fact that the nature of the analyzed EEG signals in these motor imagery tasks were not self-similar enough.

  5. Motor imagery in Asperger syndrome: testing action simulation by the hand laterality task.

    Massimiliano Conson

    Full Text Available Asperger syndrome (AS is a neurodevelopmental condition within the Autism Spectrum Disorders (ASD characterized by specific difficulties in social interaction, communication and behavioural control. In recent years, it has been suggested that ASD is related to a dysfunction of action simulation processes, but studies employing imitation or action observation tasks provided mixed results. Here, we addressed action simulation processes in adolescents with AS by means of a motor imagery task, the classical hand laterality task (to decide whether a rotated hand image is left or right; mental rotation of letters was also evaluated. As a specific marker of action simulation in hand rotation, we assessed the so-called biomechanical effect, that is the advantage for judging hand pictures showing physically comfortable versus physically awkward positions. We found the biomechanical effect in typically-developing participants but not in participants with AS. Overall performance on both hand laterality and letter rotation tasks, instead, did not differ in the two groups. These findings demonstrated a specific alteration of motor imagery skills in AS. We suggest that impaired mental simulation and imitation of goal-less movements in ASD could be related to shared cognitive mechanisms.

  6. When music tempo affects the temporal congruence between physical practice and motor imagery.

    Debarnot, Ursula; Guillot, Aymeric

    2014-06-01

    When people listen to music, they hear beat and a metrical structure in the rhythm; these perceived patterns enable coordination with the music. A clear correspondence between the tempo of actual movement (e.g., walking) and that of music has been demonstrated, but whether similar coordination occurs during motor imagery is unknown. Twenty participants walked naturally for 8m, either physically or mentally, while listening to slow and fast music, or not listening to anything at all (control condition). Executed and imagined walking times were recorded to assess the temporal congruence between physical practice (PP) and motor imagery (MI). Results showed a difference when comparing slow and fast time conditions, but each of these durations did not differ from soundless condition times, hence showing that body movement may not necessarily change in order to synchronize with music. However, the main finding revealed that the ability to achieve temporal congruence between PP and MI times was altered when listening to either slow or fast music. These data suggest that when physical movement is modulated with respect to the musical tempo, the MI efficacy of the corresponding movement may be affected by the rhythm of the music. Practical applications in sport are discussed as athletes frequently listen to music before competing while they mentally practice their movements to be performed. PMID:24681309

  7. Discrimination of Motor Imagery-Induced EEG Patterns in Patients with Complete Spinal Cord Injury

    G. Pfurtscheller

    2009-01-01

    Full Text Available EEG-based discrimination between different motor imagery states has been subject of a number of studies in healthy subjects. We investigated the EEG of 15 patients with complete spinal cord injury during imagined right hand, left hand, and feet movements. In detail we studied pair-wise discrimination functions between the 3 types of motor imagery. The following classification accuracies (mean ± SD were obtained: left versus right hand 65.03% ± 8.52, left hand versus feet 68.19% ± 11.08, and right hand versus feet 65.05% ± 9.25. In 5 out of 8 paralegic patients, the discrimination accuracy was greater than 70% but in only 1 out of 7 tetraplagic patients. The present findings provide evidence that in the majority of paraplegic patients an EEG-based BCI could achieve satisfied results. In tetraplegic patients, however, it is expected that extensive training-sessions are necessary to achieve a good BCI performance at least in some subjects.

  8. Brain oscillatory activity during motor imagery in EEG-fMRI coregistration.

    Formaggio, Emanuela; Storti, Silvia Francesca; Cerini, Roberto; Fiaschi, Antonio; Manganotti, Paolo

    2010-12-01

    The purpose of the present work was to investigate the correlation between topographical changes in brain oscillatory activity and the blood oxygenation level-dependent (BOLD) signal during a motor imagery (MI) task using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) coregistration. EEG was recorded in 7 healthy subjects inside a 1.5 T MR scanner during the imagination of the kinesthetic experience of movement. A Fast Fourier Transform was applied to EEG signal in the rest and active conditions. We used the event-related-synchronization (ERS)/desynchronization (ERD) approach to characterize where the imagination of movement produces a decrease in alpha and beta power. The mean alpha map showed ERD decrease localized over the contralateral sensory motor area (SM1c) and a light desynchronization in the ipsilateral sensory motor area (SM1i); whereas the mean beta map showed ERD decrease over the supplementary motor area (SMA). fMRI showed significant activation in SMA, SM1c, SM1i. The correlation is negative in the contralateral side and positive in the ipsilateral side. Using combined EEG-fMRI signals we obtained useful new information on the description of the changes in oscillatory activity in alpha and beta bands during MI and on the investigation of the sites of BOLD activity as possible sources in generating these rhythms. By correlating BOLD and ERD/ERS we may identify more accurately which regions contribute to changes of the electrical response. PMID:20850237

  9. Adaptive Motor Imagery: A Multimodal Study of Immobilization-Induced Brain Plasticity.

    Burianová, Hana; Sowman, Paul F; Marstaller, Lars; Rich, Anina N; Williams, Mark A; Savage, Greg; Al-Janabi, Shahd; de Lissa, Peter; Johnson, Blake W

    2016-03-01

    The consequences of losing the ability to move a limb are traumatic. One approach that examines the impact of pathological limb nonuse on the brain involves temporary immobilization of a healthy limb. Here, we investigated immobilization-induced plasticity in the motor imagery (MI) circuitry during hand immobilization. We assessed these changes with a multimodal paradigm, using functional magnetic resonance imaging (fMRI) to measure neural activation, magnetoencephalography (MEG) to track neuronal oscillatory dynamics, and transcranial magnetic stimulation (TMS) to assess corticospinal excitability. fMRI results show a significant decrease in neural activation for MI of the constrained hand, localized to sensorimotor areas contralateral to the immobilized hand. MEG results show a significant decrease in beta desynchronization and faster resynchronization in sensorimotor areas contralateral to the immobilized hand. TMS results show a significant increase in resting motor threshold in motor cortex contralateral to the constrained hand, suggesting a decrease in corticospinal excitability in the projections to the constrained hand. These results demonstrate a direct and rapid effect of immobilization on MI processes of the constrained hand, suggesting that limb nonuse may not only affect motor execution, as evidenced by previous studies, but also MI. These findings have important implications for the effectiveness of therapeutic approaches that use MI as a rehabilitation tool to ameliorate the negative effects of limb nonuse. PMID:25477368

  10. How feedback, motor imagery, and reward influence brain self-regulation using real-time fMRI.

    Sepulveda, Pradyumna; Sitaram, Ranganatha; Rana, Mohit; Montalba, Cristian; Tejos, Cristian; Ruiz, Sergio

    2016-09-01

    The learning process involved in achieving brain self-regulation is presumed to be related to several factors, such as type of feedback, reward, mental imagery, duration of training, among others. Explicitly instructing participants to use mental imagery and monetary reward are common practices in real-time fMRI (rtfMRI) neurofeedback (NF), under the assumption that they will enhance and accelerate the learning process. However, it is still not clear what the optimal strategy is for improving volitional control. We investigated the differential effect of feedback, explicit instructions and monetary reward while training healthy individuals to up-regulate the blood-oxygen-level dependent (BOLD) signal in the supplementary motor area (SMA). Four groups were trained in a two-day rtfMRI-NF protocol: GF with NF only, GF,I with NF + explicit instructions (motor imagery), GF,R with NF + monetary reward, and GF,I,R with NF + explicit instructions (motor imagery) + monetary reward. Our results showed that GF increased significantly their BOLD self-regulation from day-1 to day-2 and GF,R showed the highest BOLD signal amplitude in SMA during the training. The two groups who were instructed to use motor imagery did not show a significant learning effect over the 2 days. The additional factors, namely motor imagery and reward, tended to increase the intersubject variability in the SMA during the course of training. Whole brain univariate and functional connectivity analyses showed common as well as distinct patterns in the four groups, representing the varied influences of feedback, reward, and instructions on the brain. Hum Brain Mapp 37:3153-3171, 2016. © 2016 Wiley Periodicals, Inc. PMID:27272616

  11. Assessing the feasibility of time-resolved fNIRS to detect brain activity during motor imagery

    Abdalmalak, Androu; Milej, Daniel; Diop, Mamadou; Naci, Lorina; Owen, Adrian M.; St. Lawrence, Keith

    2016-03-01

    Functional near-infrared spectroscopy (fNIRS) is a non-invasive optical technique for detecting brain activity, which has been previously used during motor and motor executive tasks. There is an increasing interest in using fNIRS as a brain computer interface (BCI) for patients who lack the physical, but not the mental, ability to respond to commands. The goal of this study is to assess the feasibility of time-resolved fNIRS to detect brain activity during motor imagery. Stability tests were conducted to ensure the temporal stability of the signal, and motor imagery data were acquired on healthy subjects. The NIRS probes were placed on the scalp over the premotor cortex (PMC) and supplementary motor area (SMA), as these areas are responsible for motion planning. To confirm the fNIRS results, subjects underwent functional magnetic resonance imaging (fMRI) while performing the same task. Seven subjects have participated to date, and significant activation in the SMA and/or the PMC during motor imagery was detected by both fMRI and fNIRS in 4 of the 7 subjects. No activation was detected by either technique in the remaining three participants, which was not unexpected due to the nature of the task. The agreement between the two imaging modalities highlights the potential of fNIRS as a BCI, which could be adapted for bedside studies of patients with disorders of consciousness.

  12. Motor imagery in blind subjects: the influence of the previous visual experience.

    Imbiriba, Luís Aureliano; Rodrigues, Erika Carvalho; Magalhães, José; Vargas, Claudia Domingues

    2006-05-29

    Mental simulation of movements has been widely used to infer about representational aspects of action. On a daily basis, motor planning and execution depends crucially both upon vision and kinesthesia. What if the former is lost? In this study we investigate the physiological changes induced during a mental simulation task in subjects with early and late onset blindness, analyzing simultaneously stabilometric (body sway), electromyographic (EMG, lateral gastrocnemius) and eletrocardiographic (ECG) signals. Subjects were asked to stand up on a force platform and instructed either to: rest during 20s; count mentally from 1 to 15; imagine themselves executing a bilateral plantar flexion 15 times and execute the same movement 15 times. Discriminant analysis was employed to have access to the differences in the groups with respect to heart rate variability (HRV), EMG and body sway measurements for each condition. We found an overall correct classification of 100 and 90.9%, respectively, for the stabilometric parameters and HRV. This result was found only for the mental simulation task (p<0.05), being absent for resting, counting and executing. Previous studies have shown that motor simulation in a kinesthetic mode strongly associates with somatic and autonomic changes. In late blind subjects, however, movement simulation would tend to unfold with the use of both visual and kinesthetic representations. Thus, our results suggest that early and late blind subjects make use of distinct body representations during motor imagery. PMID:16530330

  13. Feature combination for classifying single-trial ECoG during motor imagery of different sessions

    Wei Qingguo; Meng Fei; Wang Yijun; Gao Xiaorong; Gao Shangkai

    2007-01-01

    The input signals of brain-computer interfaces (BCIs) may be either scalp electroencephalogram (EEG) or electrocorticogram (ECoG) recorded from subdural electrodes. To make BCIs practical, the classifiers for discriminating different brain states must have the ability of session-to-session transfer. This paper proposes an algorithm for classifying single-trial ECoG during motor imagery of different sessions. Three features, derived from two physiological phenomena, movement-related potentials (MRP) and event-related desynchronization (ERD), and extracted by common spatial subspace decomposition (CSSD) and waveform mean, are combined to perform classification tasks. The specific signal processing methods utilized are described in detail. The algorithm was successfully applied to Data Set I of BCI Competition Ⅲ, and achieved a classification accuracy of 91% on test set.

  14. Multisubject Learning for Common Spatial Patterns in Motor-Imagery BCI

    Dieter Devlaminck

    2011-01-01

    Full Text Available Motor-imagery-based brain-computer interfaces (BCIs commonly use the common spatial pattern filter (CSP as preprocessing step before feature extraction and classification. The CSP method is a supervised algorithm and therefore needs subject-specific training data for calibration, which is very time consuming to collect. In order to reduce the amount of calibration data that is needed for a new subject, one can apply multitask (from now on called multisubject machine learning techniques to the preprocessing phase. Here, the goal of multisubject learning is to learn a spatial filter for a new subject based on its own data and that of other subjects. This paper outlines the details of the multitask CSP algorithm and shows results on two data sets. In certain subjects a clear improvement can be seen, especially when the number of training trials is relatively low.

  15. Investigating brief motor imagery for an ERD/ERS based BCI.

    Thomas, Eoin; Fruitet, Joan; Clerc, Maureen

    2012-01-01

    This study establishes the effectiveness of event related synchronisation (ERS) features for a system paced brain computer interface (BCI). In particular, the relationship between the duration of motor imagery (MI) and the quality of the features extracted from the ERS is investigated. To this end, two groups of users performed brief (2s) or sustained (4s) MI, and offline single trial BCIs were validated on each group based on features extracted from the EEG before, during and after MI. The BCIs were designed to recognise two intentional control tasks and a no-control state. Cross-validated results indicate that brief MI leads to more informative ERS features than sustained MI. PMID:23366538

  16. Quaternion-Based Signal Analysis for Motor Imagery Classification from Electroencephalographic Signals

    Patricia Batres-Mendoza

    2016-03-01

    Full Text Available Quaternions can be used as an alternative to model the fundamental patterns of electroencephalographic (EEG signals in the time domain. Thus, this article presents a new quaternion-based technique known as quaternion-based signal analysis (QSA to represent EEG signals obtained using a brain-computer interface (BCI device to detect and interpret cognitive activity. This quaternion-based signal analysis technique can extract features to represent brain activity related to motor imagery accurately in various mental states. Experimental tests in which users where shown visual graphical cues related to left and right movements were used to collect BCI-recorded signals. These signals were then classified using decision trees (DT, support vector machine (SVM and k-nearest neighbor (KNN techniques. The quantitative analysis of the classifiers demonstrates that this technique can be used as an alternative in the EEG-signal modeling phase to identify mental states.

  17. Implementation of Motor Imagery during Specific Aerobic Training Session in Young Tennis Players

    Guillot, Aymeric; Di Rienzo, Franck; Pialoux, Vincent; Simon, Germain; Skinner, Sarah; Rogowski, Isabelle

    2015-01-01

    The aim of this study was to investigate the effects of implementing motor imagery (MI) during specific tennis high intensity intermittent training (HIIT) sessions on groundstroke performance in young elite tennis players. Stroke accuracy and ball velocity of forehand and backhand drives were evaluated in ten young tennis players, immediately before and after having randomly performed two HIIT sessions. One session included MI exercises during the recovery phases, while the other included verbal encouragements for physical efforts and served as control condition. Results revealed that similar cardiac demand was observed during both sessions, while implementing MI maintained groundstroke accuracy. Embedding MI during HIIT enabled the development of physical fitness and the preservation of stroke performance. These findings bring new insight to tennis and conditioning coaches in order to fulfil the benefits of specific playing HIIT sessions, and therefore to optimise the training time. PMID:26580804

  18. Implementation of Motor Imagery during Specific Aerobic Training Session in Young Tennis Players.

    Aymeric Guillot

    Full Text Available The aim of this study was to investigate the effects of implementing motor imagery (MI during specific tennis high intensity intermittent training (HIIT sessions on groundstroke performance in young elite tennis players. Stroke accuracy and ball velocity of forehand and backhand drives were evaluated in ten young tennis players, immediately before and after having randomly performed two HIIT sessions. One session included MI exercises during the recovery phases, while the other included verbal encouragements for physical efforts and served as control condition. Results revealed that similar cardiac demand was observed during both sessions, while implementing MI maintained groundstroke accuracy. Embedding MI during HIIT enabled the development of physical fitness and the preservation of stroke performance. These findings bring new insight to tennis and conditioning coaches in order to fulfil the benefits of specific playing HIIT sessions, and therefore to optimise the training time.

  19. Quaternion-Based Signal Analysis for Motor Imagery Classification from Electroencephalographic Signals.

    Batres-Mendoza, Patricia; Montoro-Sanjose, Carlos R; Guerra-Hernandez, Erick I; Almanza-Ojeda, Dora L; Rostro-Gonzalez, Horacio; Romero-Troncoso, Rene J; Ibarra-Manzano, Mario A

    2016-01-01

    Quaternions can be used as an alternative to model the fundamental patterns of electroencephalographic (EEG) signals in the time domain. Thus, this article presents a new quaternion-based technique known as quaternion-based signal analysis (QSA) to represent EEG signals obtained using a brain-computer interface (BCI) device to detect and interpret cognitive activity. This quaternion-based signal analysis technique can extract features to represent brain activity related to motor imagery accurately in various mental states. Experimental tests in which users where shown visual graphical cues related to left and right movements were used to collect BCI-recorded signals. These signals were then classified using decision trees (DT), support vector machine (SVM) and k-nearest neighbor (KNN) techniques. The quantitative analysis of the classifiers demonstrates that this technique can be used as an alternative in the EEG-signal modeling phase to identify mental states. PMID:26959029

  20. Quaternion-Based Signal Analysis for Motor Imagery Classification from Electroencephalographic Signals

    Batres-Mendoza, Patricia; Montoro-Sanjose, Carlos R.; Guerra-Hernandez, Erick I.; Almanza-Ojeda, Dora L.; Rostro-Gonzalez, Horacio; Romero-Troncoso, Rene J.; Ibarra-Manzano, Mario A.

    2016-01-01

    Quaternions can be used as an alternative to model the fundamental patterns of electroencephalographic (EEG) signals in the time domain. Thus, this article presents a new quaternion-based technique known as quaternion-based signal analysis (QSA) to represent EEG signals obtained using a brain-computer interface (BCI) device to detect and interpret cognitive activity. This quaternion-based signal analysis technique can extract features to represent brain activity related to motor imagery accurately in various mental states. Experimental tests in which users where shown visual graphical cues related to left and right movements were used to collect BCI-recorded signals. These signals were then classified using decision trees (DT), support vector machine (SVM) and k-nearest neighbor (KNN) techniques. The quantitative analysis of the classifiers demonstrates that this technique can be used as an alternative in the EEG-signal modeling phase to identify mental states. PMID:26959029

  1. Quantifying the role of motor imagery in brain-machine interfaces

    Marchesotti, Silvia; Bassolino, Michela; Serino, Andrea; Bleuler, Hannes; Blanke, Olaf

    2016-04-01

    Despite technical advances in brain machine interfaces (BMI), for as-yet unknown reasons the ability to control a BMI remains limited to a subset of users. We investigate whether individual differences in BMI control based on motor imagery (MI) are related to differences in MI ability. We assessed whether differences in kinesthetic and visual MI, in the behavioral accuracy of MI, and in electroencephalographic variables, were able to differentiate between high- versus low-aptitude BMI users. High-aptitude BMI users showed higher MI accuracy as captured by subjective and behavioral measurements, pointing to a prominent role of kinesthetic rather than visual imagery. Additionally, for the first time, we applied mental chronometry, a measure quantifying the degree to which imagined and executed movements share a similar temporal profile. We also identified enhanced lateralized μ-band oscillations over sensorimotor cortices during MI in high- versus low-aptitude BMI users. These findings reveal that subjective, behavioral, and EEG measurements of MI are intimately linked to BMI control. We propose that poor BMI control cannot be ascribed only to intrinsic limitations of EEG recordings and that specific questionnaires and mental chronometry can be used as predictors of BMI performance (without the need to record EEG activity).

  2. Non-invasive detection of high gamma band activity during motor imagery

    Melissa M Smith

    2014-10-01

    Full Text Available High gamma oscillations (70-150 Hz; HG are rapidly evolving, spatially localized neurophysiological signals that are believed to be the best representative signature of engaged neural populations. The HG band has been best characterized from invasive electrophysiological approaches such as electrocorticography (ECoG because of the increased signal-to-noise ratio that results when by-passing the scalp and skull. Despite the recent observation that HG activity can be detected non-invasively by electroencephalography (EEG, it is unclear to what extent EEG can accurately resolve the spatial distribution of HG signals during active task engagement. We have overcome some of the limitations inherent to acquiring HG signals across the scalp by utilizing individual head anatomy in combination with an inverse modeling method. We applied a linearly constrained minimum variance beamformer (LCMV method on EEG data during a motor imagery paradigm to extract a time-frequency spectrogram at every voxel location on the cortex. To confirm spatially distributed patterns of HG responses, we contrasted overlapping maps of the EEG HG signal with BOLD fMRI data acquired from the same set of neurologically normal subjects during a separate session. We show that scalp-based HG band activity detected by EEG during motor imagery spatially co-localizes with BOLD fMRI data. Taken together, these results suggest that EEG can accurately resolve spatially specific estimates of local cortical high frequency signals, potentially opening an avenue for non-invasive measurement of HG potentials from diverse sets of neurologically impaired populations for diagnostic and therapeutic purposes

  3. EEG and behavioural correlates of different forms of motor imagery during action observation in rhythmical actions.

    Eaves, D L; Behmer, L P; Vogt, S

    2016-07-01

    Recent studies show that participants can engage in motor imagery (MI) and action observation (AO) simultaneously (AO+MI), indicating a capacity for dual action simulation. Here we studied the electrophysiological correlates and behavioural outcomes of two forms of AO+MI, along with pure MI and pure AO control conditions. In synchronised AO+MI, participants imagined performing a rhythmical action in synchrony with an observed distractor action. In contrast in static AO+MI, where the imagery served to conflict with AO, participants imagined holding a static hand posture during AO. Following synchronised AO+MI, rhythmical execution was strongly biased toward the cycle time of the previously observed rhythm ('imitation bias'), whereas a weaker bias was found following pure MI, and particularly for static AO+MI. In line with these findings, event-related desynchronisation (ERD) in primary sensorimotor and parietal regions was more pronounced in synchronised AO+MI compared to both pure AO and pure MI. These ERD amplitudes were, however, highly similar for static and synchronised AO+MI; suggesting that, regardless of co-represented content, both AO+MI states produced stronger motor activations than single action simulation. In contrast, synchronised AO+MI produced significantly stronger ERD in rostral prefrontal cortex compared to the other three conditions. This specific rostral prefrontal involvement most likely reflected additional cognitive processing for aligning dual action simulations. Together these results provide an important empirical validation of different AO+MI states, in that the imitation bias was strongly modulated by the content of the AO+MI instructions, and that synchronised AO+MI produced stronger behavioural and neurophysiological effects compared to pure AO or MI. PMID:27266395

  4. An Algorithm for Idle-State Detection in Motor-Imagery-Based Brain-Computer Interface

    Yijun Wang

    2007-07-01

    Full Text Available For a robust brain-computer interface (BCI system based on motor imagery (MI, it should be able to tell when the subject is not concentrating on MI tasks (the “idle state” so that real MI tasks could be extracted accurately. Moreover, because of the diversity of idle state, detecting idle state without training samples is as important as classifying MI tasks. In this paper, we propose an algorithm for solving this problem. A three-class classifier was constructed by combining two two-class classifiers, one specified for idle-state detection and the other for these two MI tasks. Common spatial subspace decomposition (CSSD was used to extract the features of event-related desynchronization (ERD in two motor imagery tasks. Then Fisher discriminant analysis (FDA was employed in the design of two two-class classifiers for completion of detecting each task, respectively. The algorithm successfully provided a way to solve the problem of “idle-state detection without training samples.” The algorithm was applied to the dataset IVc from BCI competition III. A final result with mean square error of 0.30 was obtained on the testing set. This is the winning algorithm in BCI competition III. In addition, the algorithm was also validated by applying to the EEG data of an MI experiment including “idle” task.

  5. Role of the primary motor cortex in the early boost in performance following mental imagery training.

    Ursula Debarnot

    Full Text Available 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.

  6. 2013 Rio Puerto Nuevo, Puerto Rico ADS40 4-Band Imagery

    National Oceanic and Atmospheric Administration, Department of Commerce — Imagery acquired with airborne sensors contain camera and terrain related distortions which make the images unsuitable for geospatial analysis as positions within...

  7. 2014 Horry County, SC ADS80 4-Band 8 Bit Imagery

    National Oceanic and Atmospheric Administration, Department of Commerce — All imagery was collected during the 2014 Spring flying season during leaf-off conditions for deciduous vegetation in the State of South Carolina. The sun angle was...

  8. Mental representation and mental practice: experimental investigation on the functional links between motor memory and motor imagery.

    Frank, Cornelia; Land, William M; Popp, Carmen; Schack, Thomas

    2014-01-01

    Recent research on mental representation of complex action has revealed distinct differences in the structure of representational frameworks between experts and novices. More recently, research on the development of mental representation structure has elicited functional changes in novices' representations as a result of practice. However, research investigating if and how mental practice adds to this adaptation process is lacking. In the present study, we examined the influence of mental practice (i.e., motor imagery rehearsal) on both putting performance and the development of one's representation of the golf putt during early skill acquisition. Novice golfers (N = 52) practiced the task of golf putting under one of four different practice conditions: mental, physical, mental-physical combined, and no practice. Participants were tested prior to and after a practice phase, as well as after a three day retention interval. Mental representation structures of the putt were measured, using the structural dimensional analysis of mental representation. This method provides psychometric data on the distances and groupings of basic action concepts in long-term memory. Additionally, putting accuracy and putting consistency were measured using two-dimensional error scores of each putt. Findings revealed significant performance improvements over the course of practice together with functional adaptations in mental representation structure. Interestingly, after three days of practice, the mental representations of participants who incorporated mental practice into their practice regime displayed representation structures that were more similar to a functional structure than did participants who did not incorporate mental practice. The findings of the present study suggest that mental practice promotes the cognitive adaptation process during motor learning, leading to more elaborate representations than physical practice only. PMID:24743576

  9. Mental representation and mental practice: experimental investigation on the functional links between motor memory and motor imagery.

    Cornelia Frank

    Full Text Available Recent research on mental representation of complex action has revealed distinct differences in the structure of representational frameworks between experts and novices. More recently, research on the development of mental representation structure has elicited functional changes in novices' representations as a result of practice. However, research investigating if and how mental practice adds to this adaptation process is lacking. In the present study, we examined the influence of mental practice (i.e., motor imagery rehearsal on both putting performance and the development of one's representation of the golf putt during early skill acquisition. Novice golfers (N = 52 practiced the task of golf putting under one of four different practice conditions: mental, physical, mental-physical combined, and no practice. Participants were tested prior to and after a practice phase, as well as after a three day retention interval. Mental representation structures of the putt were measured, using the structural dimensional analysis of mental representation. This method provides psychometric data on the distances and groupings of basic action concepts in long-term memory. Additionally, putting accuracy and putting consistency were measured using two-dimensional error scores of each putt. Findings revealed significant performance improvements over the course of practice together with functional adaptations in mental representation structure. Interestingly, after three days of practice, the mental representations of participants who incorporated mental practice into their practice regime displayed representation structures that were more similar to a functional structure than did participants who did not incorporate mental practice. The findings of the present study suggest that mental practice promotes the cognitive adaptation process during motor learning, leading to more elaborate representations than physical practice only.

  10. Motor imagery during action observation modulates automatic imitation effects in rhythmical actions

    Daniel Lloyd Eaves

    2014-02-01

    Full Text Available We have previously shown that passively observing a task-irrelevant rhythmical action can bias the cycle time of a subsequently executed rhythmical action. Here we use the same paradigm to investigate the impact of different forms of motor imagery (MI during action observation (AO on this automatic imitation (AI effect. Participants saw a picture of the instructed action followed by a rhythmical distractor movie, wherein cycle time was subtly manipulated across trials. They then executed the instructed rhythmical action. When participants imagined performing the instructed action in synchrony with the distractor action (AO + MI, a strong imitation bias was found that was significantly greater than in our previous study. The bias was pronounced equally for compatible and incompatible trials, wherein observed and imagined actions were different in type (e.g., face washing vs. painting or plane of movement, or both. In contrast, no imitation bias was observed when MI conflicted with AO. In Experiment 2, motor execution synchronised with AO produced a stronger imitation bias compared to AO + MI, showing an advantage in synchronisation for overt execution over MI. Furthermore, the bias was stronger when participants synchronised the instructed action with the distractor movie, compared to when they synchronised the distractor action with the distractor movie. Although we still observed a significant bias in the latter condition, this finding indicates a degree of specificity in AI effects for the identity of the synchronised action. Overall, our data show that MI can substantially modulate the effects of AO on subsequent execution, wherein: (1 combined AO + MI can enhance AI effects relative to passive AO; (2 observed and imagined actions can be flexibly coordinated across different action types and planes; and (3 conflicting AO + MI can abolish AI effects. Therefore, combined AO + MI instructions should be considered in motor training and

  11. EEG classification for motor imagery and resting state in BCI applications using multi-class Adaboost extreme learning machine

    Gao, Lin; Cheng, Wei; Zhang, Jinhua; Wang, Jue

    2016-08-01

    Brain-computer interface (BCI) systems provide an alternative communication and control approach for people with limited motor function. Therefore, the feature extraction and classification approach should differentiate the relative unusual state of motion intention from a common resting state. In this paper, we sought a novel approach for multi-class classification in BCI applications. We collected electroencephalographic (EEG) signals registered by electrodes placed over the scalp during left hand motor imagery, right hand motor imagery, and resting state for ten healthy human subjects. We proposed using the Kolmogorov complexity (Kc) for feature extraction and a multi-class Adaboost classifier with extreme learning machine as base classifier for classification, in order to classify the three-class EEG samples. An average classification accuracy of 79.5% was obtained for ten subjects, which greatly outperformed commonly used approaches. Thus, it is concluded that the proposed method could improve the performance for classification of motor imagery tasks for multi-class samples. It could be applied in further studies to generate the control commands to initiate the movement of a robotic exoskeleton or orthosis, which finally facilitates the rehabilitation of disabled people.

  12. The influence of action possibility and end-state comfort on motor imagery of manual action sequences.

    Seegelke, Christian; Hughes, Charmayne M L

    2015-12-01

    It has been proposed that the preparation of goal-direct actions involves internal movement simulation, or motor imagery. Evidence suggests that motor imagery is critically involved in the prediction of action consequences and contributes heavily to movement planning processes. The present study examined whether the sensitivity towards end-state comfort and the possibility/impossibility to perform an action sequence are considered during motor imagery. Participants performed a mental rotation task in which two images were simultaneously presented. The image on the left depicted the start posture of a right hand when grasping a bar, while the right image depicted the hand posture at the end of the action sequence. The right image displayed the bar in a vertical orientation with the hand in a comfortable (thumb-up) or in an uncomfortable (thumb-down) posture, while the bar in the left image was rotated in picture plane in steps of 45°. Crucially, the two images formed either a physically possible or physically impossible to perform action sequence. Results revealed strikingly different response time patterns for the two action sequence conditions. In general, response times increased almost monotonically with increasing angular disparity for the possible to perform action sequences. However, slight deviations from this monotonicity were apparent when the sequences contained an uncomfortable as opposed to a comfortable final posture. In contrast, for the impossible sequences, response times did not follow a typical mental rotation function, but instead were uniformly very slow. These findings suggest that both biomechanical constraints (i.e., end-state comfort) and the awareness of the possibility/impossibility to perform an action sequence are considered during motor imagery. We conclude that motor representations contain information about the spatiotemporal movement organization and the possibility of performing an action, which are crucially involved in

  13. Long-lasting cortical reorganization as the result of motor imagery of throwing a ball in a virtual tennis court

    Ana-Maria eCebolla

    2015-12-01

    Full Text Available In order to characterize the neural signature of a motor imagery (MI task, the present study investigates for the first time the oscillation characteristics including both of the time-frequency measurements, event related spectral perturbation (ERSP and intertrial coherence (ITC underlying the variations in the temporal measurements (ERP directly related to a motor imagery task. We hypothesize that significant variations in both of the time-frequency measurements underlie the specific changes in the ERP directly related to motor imagery. For the motor imagery task, we chose a simple everyday task (throwing a tennis ball, that does not require any particular motor expertise, set within the controlled virtual reality scenario of a tennis court. When compared to the rest condition a consistent, long-lasting negative fronto-central ERP wave was accompanied by significant changes in both time frequency measurements suggesting long-lasting cortical activity reorganization. The ERP wave was characterised by two peaks at about 300 ms (N300 and 1000 ms (N1000. The N300 component was centrally localized on the scalp and was accompanied by significant phase consistency in the delta brain rhythms in the contralateral central scalp areas. The N1000 component spread wider centrally and was accompanied by a significant power decrease (or ERD in low beta brain rhythms localized in fronto-precentral and parieto-occipital scalp areas and also by a significant power increase (or ERS in theta brain rhythms spreading fronto-centrally. During the transition from N300 to N1000, a contralateral alpha (mu as well as post-central and parieto- theta rhythms occurred. The visual representation of movement formed in the minds of participants might underlie a top-down process from the fronto-central areas which is reflected by the amplitude changes observed in the fronto-central ERPs and by the significant phase synchrony in contralateral fronto-central delta and

  14. The effect of leisure activity golf practice on motor imagery: an fMRI study in middle adulthood

    Ladina eBezzola

    2012-03-01

    Full Text Available Much is known about practice-induced plasticity of the motor system. But it is not clear whether the activity in the motor network induced by mental motor imagery is influenced by actually practicing the imagined motor tasks.In a longitudinal study design with two measurement time-points, functional magnetic resonance imaging (fMRI was used to explore dynamic changes in the brain in response to training of highly complex movements by participants of 40 to 60 years of age. The investigated motor learning task entailed golf training practiced by novices as leisure activity. Additionally, data from an age and sex-matched control group without golf training was collected.Results show increased hemodynamic responses during mental rehearsal of a golf swing in non-primary cortical motor areas, sub-cortical motor areas, and parietal regions of the novice golfers and the control subjects. This result complements previous mental imagery research that shows involvement of motor areas during mental rehearsal of a complex movement, especially in subjects with low skill level. More importantly, changes were only found between the two measurement time-points in the golf novice group with a decrease in hemodynamic responses in non-primary motor areas after the 40 hours of golf practice. Thus, the results indicate that a complex physical leisure activity induces functional neuroplasticity in the seldom studied population of middle-aged adults, and that this effect is evident during mental rehearsal of the practiced task. This finding supports the idea that (a a skill improvement is associated with a modified activation pattern in the associated neuronal network that can be identified during mental rehearsal of the practiced task, and that (b a strict training protocol is not necessary to induce functional neuroplasticity.

  15. Classification of Two Class Motor Imagery Tasks Using Hybrid GA-PSO Based K-Means Clustering

    Suraj; Purnendu Tiwari; Subhojit Ghosh; Rakesh Kumar Sinha

    2015-01-01

    Transferring the brain computer interface (BCI) from laboratory condition to meet the real world application needs BCI to be applied asynchronously without any time constraint. High level of dynamism in the electroencephalogram (EEG) signal reasons us to look toward evolutionary algorithm (EA). Motivated by these two facts, in this work a hybrid GA-PSO based K-means clustering technique has been used to distinguish two class motor imagery (MI) tasks. The proposed hybrid GA-PSO based K-means c...

  16. Motor imagery-based skill acquisition disrupted following rTMS of the inferior parietal lobule.

    Kraeutner, Sarah N; Keeler, Laura T; Boe, Shaun G

    2016-02-01

    Motor imagery (MI), the mental rehearsal of motor tasks, has promise as a therapy in post-stroke rehabilitation. The potential effectiveness of MI is attributed to the facilitation of plasticity in numerous brain regions akin to those recruited for physical practice. It is suggested, however, that MI relies more heavily on regions commonly affected post-stroke, including left hemisphere parietal regions involved in visuospatial processes. However, the impact of parietal damage on MI-based skill acquisition that underlies rehabilitation remains unclear. Here, we examine the contribution of the left inferior parietal lobule (IPL) to MI using inhibitory transcranial magnetic stimulation (TMS) and an MI-based implicit sequence learning (ISL) paradigm. Participants (N = 27) completed the MI-based ISL paradigm after receiving continuous theta burst stimulation to the left IPL (TMS), or with the coil angled away from the scalp (sham). Reaction time differences (dRT) and effect sizes between implicit and random sequences assessed success of MI-based learning. Mean dRT for the sham group was 36.1 ± 28.2 ms (d = 0.71). Mean dRT in the TMS group was 7.7 ± 38.5 ms (d = 0.11). These results indicate that inhibition of the left IPL impaired MI-based learning. We conclude that the IPL and likely the visuospatial processes it mediates are critical for MI performance and thus MI-based skill acquisition or learning. Ultimately, these findings have implications for the use of MI in post-stroke rehabilitation. PMID:26487181

  17. Haptic, Virtual Interaction and Motor Imagery: Entertainment Tools and Psychophysiological Testing

    Sara Invitto

    2016-03-01

    Full Text Available In this work, the perception of affordances was analysed in terms of cognitive neuroscience during an interactive experience in a virtual reality environment. In particular, we chose a virtual reality scenario based on the Leap Motion controller: this sensor device captures the movements of the user’s hand and fingers, which are reproduced on a computer screen by the proper software applications. For our experiment, we employed a sample of 10 subjects matched by age and sex and chosen among university students. The subjects took part in motor imagery training and immersive affordance condition (a virtual training with Leap Motion and a haptic training with real objects. After each training sessions the subject performed a recognition task, in order to investigate event-related potential (ERP components. The results revealed significant differences in the attentional components during the Leap Motion training. During Leap Motion session, latencies increased in the occipital lobes, which are entrusted to visual sensory; in contrast, latencies decreased in the frontal lobe, where the brain is mainly activated for attention and action planning.

  18. Haptic, Virtual Interaction and Motor Imagery: Entertainment Tools and Psychophysiological Testing

    Invitto, Sara; Faggiano, Chiara; Sammarco, Silvia; De Luca, Valerio; De Paolis, Lucio T.

    2016-01-01

    In this work, the perception of affordances was analysed in terms of cognitive neuroscience during an interactive experience in a virtual reality environment. In particular, we chose a virtual reality scenario based on the Leap Motion controller: this sensor device captures the movements of the user’s hand and fingers, which are reproduced on a computer screen by the proper software applications. For our experiment, we employed a sample of 10 subjects matched by age and sex and chosen among university students. The subjects took part in motor imagery training and immersive affordance condition (a virtual training with Leap Motion and a haptic training with real objects). After each training sessions the subject performed a recognition task, in order to investigate event-related potential (ERP) components. The results revealed significant differences in the attentional components during the Leap Motion training. During Leap Motion session, latencies increased in the occipital lobes, which are entrusted to visual sensory; in contrast, latencies decreased in the frontal lobe, where the brain is mainly activated for attention and action planning. PMID:26999151

  19. Haptic, Virtual Interaction and Motor Imagery: Entertainment Tools and Psychophysiological Testing.

    Invitto, Sara; Faggiano, Chiara; Sammarco, Silvia; De Luca, Valerio; De Paolis, Lucio T

    2016-01-01

    In this work, the perception of affordances was analysed in terms of cognitive neuroscience during an interactive experience in a virtual reality environment. In particular, we chose a virtual reality scenario based on the Leap Motion controller: this sensor device captures the movements of the user's hand and fingers, which are reproduced on a computer screen by the proper software applications. For our experiment, we employed a sample of 10 subjects matched by age and sex and chosen among university students. The subjects took part in motor imagery training and immersive affordance condition (a virtual training with Leap Motion and a haptic training with real objects). After each training sessions the subject performed a recognition task, in order to investigate event-related potential (ERP) components. The results revealed significant differences in the attentional components during the Leap Motion training. During Leap Motion session, latencies increased in the occipital lobes, which are entrusted to visual sensory; in contrast, latencies decreased in the frontal lobe, where the brain is mainly activated for attention and action planning. PMID:26999151

  20. A Study of Various Feature Extraction Methods on a Motor Imagery Based Brain Computer Interface System

    Resalat, Seyed Navid; Saba, Valiallah

    2016-01-01

    Introduction: Brain Computer Interface (BCI) systems based on Movement Imagination (MI) are widely used in recent decades. Separate feature extraction methods are employed in the MI data sets and classified in Virtual Reality (VR) environments for real-time applications. Methods: This study applied wide variety of features on the recorded data using Linear Discriminant Analysis (LDA) classifier to select the best feature sets in the offline mode. The data set was recorded in 3-class tasks of the left hand, the right hand, and the foot motor imagery. Results: The experimental results showed that Auto-Regressive (AR), Mean Absolute Value (MAV), and Band Power (BP) features have higher accuracy values,75% more than those for the other features. Discussion: These features were selected for the designed real-time navigation. The corresponding results revealed the subject-specific nature of the MI-based BCI system; however, the Power Spectral Density (PSD) based α-BP feature had the highest averaged accuracy.

  1. Multiresolution analysis over graphs for a motor imagery based online BCI game.

    Asensio-Cubero, Javier; Gan, John Q; Palaniappan, Ramaswamy

    2016-01-01

    Multiresolution analysis (MRA) over graph representation of EEG data has proved to be a promising method for offline brain-computer interfacing (BCI) data analysis. For the first time we aim to prove the feasibility of the graph lifting transform in an online BCI system. Instead of developing a pointer device or a wheel-chair controller as test bed for human-machine interaction, we have designed and developed an engaging game which can be controlled by means of imaginary limb movements. Some modifications to the existing MRA analysis over graphs for BCI have also been proposed, such as the use of common spatial patterns for feature extraction at the different levels of decomposition, and sequential floating forward search as a best basis selection technique. In the online game experiment we obtained for three classes an average classification rate of 63.0% for fourteen naive subjects. The application of a best basis selection method helps significantly decrease the computing resources needed. The present study allows us to further understand and assess the benefits of the use of tailored wavelet analysis for processing motor imagery data and contributes to the further development of BCI for gaming purposes. PMID:26599827

  2. The comparison between motor imagery and verbal rehearsal on the learning of sequential movements

    Arnaud eSaimpont

    2013-11-01

    Full Text Available Mental practice refers to the cognitive rehearsal of a physical activity. It is widely used by athletes to enhance their performance and its efficiency to help train motor function in people with physical disabilities is now recognized. Mental practice is generally based on motor imagery (MI i.e. the conscious simulation of a movement without its actual execution. It may also be based on verbal rehearsal (VR i.e. the silent rehearsal of the labels associated with an action. In this study, the effect of MI training or VR on the learning and retention of a foot-sequence task was investigated. Thirty right-footed subjects, aged between 22 and 37 years old (mean: 27.4±4.1 years and randomly assigned to one of three groups, practiced a serial reaction time task involving a sequence of three dorsiflexions and three plantar flexions with the left foot. One group (n=10 mentally practiced the sequence with MI for five weeks, another group (n=10 mentally practiced the sequence with VR of the foot positions for the same duration, and a control group (n=10 did not practice the sequence mentally. The time to perform the practiced sequence as well as an unpracticed sequence was recorded before training, immediately after training and six months after training (retention. The main results showed that the speed improvement after training was significantly greater in the MI group compared to the control group and tended to be greater in the VR group compared to the control group. The improvement in performance did not differ in the MI and VR groups. At retention, however, no difference in response times was found among the three groups, indicating that the effect of mental practice did not last over a long period without training. Interestingly, this pattern of results was similar for the practiced and non-practiced sequence. Overall, these results suggest that both MI training and VR help to improve motor performance and that mental practice may induce non

  3. Supplementary motor area and primary auditory cortex activation in an expert break-dancer during the kinesthetic motor imagery of dance to music.

    Olshansky, Michael P; Bar, Rachel J; Fogarty, Mary; DeSouza, Joseph F X

    2015-01-01

    The current study used functional magnetic resonance imaging to examine the neural activity of an expert dancer with 35 years of break-dancing experience during the kinesthetic motor imagery (KMI) of dance accompanied by highly familiar and unfamiliar music. The goal of this study was to examine the effect of musical familiarity on neural activity underlying KMI within a highly experienced dancer. In order to investigate this in both primary sensory and motor planning cortical areas, we examined the effects of music familiarity on the primary auditory cortex [Heschl's gyrus (HG)] and the supplementary motor area (SMA). Our findings reveal reduced HG activity and greater SMA activity during imagined dance to familiar music compared to unfamiliar music. We propose that one's internal representations of dance moves are influenced by auditory stimuli and may be specific to a dance style and the music accompanying it. PMID:25301352

  4. Improving the discrimination of hand motor imagery via virtual reality based visual guidance.

    Liang, Shuang; Choi, Kup-Sze; Qin, Jing; Pang, Wai-Man; Wang, Qiong; Heng, Pheng-Ann

    2016-08-01

    While research on the brain-computer interface (BCI) has been active in recent years, how to get high-quality electrical brain signals to accurately recognize human intentions for reliable communication and interaction is still a challenging task. The evidence has shown that visually guided motor imagery (MI) can modulate sensorimotor electroencephalographic (EEG) rhythms in humans, but how to design and implement efficient visual guidance during MI in order to produce better event-related desynchronization (ERD) patterns is still unclear. The aim of this paper is to investigate the effect of using object-oriented movements in a virtual environment as visual guidance on the modulation of sensorimotor EEG rhythms generated by hand MI. To improve the classification accuracy on MI, we further propose an algorithm to automatically extract subject-specific optimal frequency and time bands for the discrimination of ERD patterns produced by left and right hand MI. The experimental results show that the average classification accuracy of object-directed scenarios is much better than that of non-object-directed scenarios (76.87% vs. 69.66%). The result of the t-test measuring the difference between them is statistically significant (p = 0.0207). When compared to algorithms based on fixed frequency and time bands, contralateral dominant ERD patterns can be enhanced by using the subject-specific optimal frequency and the time bands obtained by our proposed algorithm. These findings have the potential to improve the efficacy and robustness of MI-based BCI applications. PMID:27282228

  5. Comparison Analysis: Granger Causality and New Causality and Their Applications to Motor Imagery.

    Hu, Sanqing; Wang, Hui; Zhang, Jianhai; Kong, Wanzeng; Cao, Yu; Kozma, Robert

    2016-07-01

    In this paper we first point out a fatal drawback that the widely used Granger causality (GC) needs to estimate the autoregressive model, which is equivalent to taking a series of backward recursive operations which are infeasible in many irreversible chemical reaction models. Thus, new causality (NC) proposed by Hu et al. (2011) is theoretically shown to be more sensitive to reveal true causality than GC. We then apply GC and NC to motor imagery (MI) which is an important mental process in cognitive neuroscience and psychology and has received growing attention for a long time. We study causality flow during MI using scalp electroencephalograms from nine subjects in Brain-computer interface competition IV held in 2008. We are interested in three regions: Cz (central area of the cerebral cortex), C3 (left area of the cerebral cortex), and C4 (right area of the cerebral cortex) which are considered to be optimal locations for recognizing MI states in the literature. Our results show that: 1) there is strong directional connectivity from Cz to C3/C4 during left- and right-hand MIs based on GC and NC; 2) during left-hand MI, there is directional connectivity from C4 to C3 based on GC and NC; 3) during right-hand MI, there is strong directional connectivity from C3 to C4 which is much clearly revealed by NC than by GC, i.e., NC largely improves the classification rate; and 4) NC is demonstrated to be much more sensitive to reveal causal influence between different brain regions than GC. PMID:26099149

  6. Dynamic frequency feature selection based approach for classification of motor imageries.

    Luo, Jing; Feng, Zuren; Zhang, Jun; Lu, Na

    2016-08-01

    Electroencephalography (EEG) is one of the most popular techniques to record the brain activities such as motor imagery, which is of low signal-to-noise ratio and could lead to high classification error. Therefore, selection of the most discriminative features could be crucial to improve the classification performance. However, the traditional feature selection methods employed in brain-computer interface (BCI) field (e.g. Mutual Information-based Best Individual Feature (MIBIF), Mutual Information-based Rough Set Reduction (MIRSR) and cross-validation) mainly focus on the overall performance on all the trials in the training set, and thus may have very poor performance on some specific samples, which is not acceptable. To address this problem, a novel sequential forward feature selection approach called Dynamic Frequency Feature Selection (DFFS) is proposed in this paper. The DFFS method emphasized the importance of the samples that got misclassified while only pursuing high overall classification performance. In the DFFS based classification scheme, the EEG data was first transformed to frequency domain using Wavelet Packet Decomposition (WPD), which is then employed as the candidate set for further discriminatory feature selection. The features are selected one by one in a boosting manner. After one feature being selected, the importance of the correctly classified samples based on the feature will be decreased, which is equivalent to increasing the importance of the misclassified samples. Therefore, a complement feature to the current features could be selected in the next run. The selected features are then fed to a classifier trained by random forest algorithm. Finally, a time series voting-based method is utilized to improve the classification performance. Comparisons between the DFFS-based approach and state-of-art methods on BCI competition IV data set 2b have been conducted, which have shown the superiority of the proposed algorithm. PMID:27253616

  7. High theta and low alpha powers may be indicative of BCI-illiteracy in motor imagery.

    Minkyu Ahn

    Full Text Available In most brain computer interface (BCI systems, some target users have significant difficulty in using BCI systems. Such target users are called 'BCI-illiterate'. This phenomenon has been poorly investigated, and a clear understanding of the BCI-illiteracy mechanism or a solution to this problem has not been reported to date. In this study, we sought to demonstrate the neurophysiological differences between two groups (literate, illiterate with a total of 52 subjects. We investigated recordings under non-task related state (NTS which is collected during subject is relaxed with eyes open. We found that high theta and low alpha waves were noticeable in the BCI-illiterate relative to the BCI-literate people. Furthermore, these high theta and low alpha wave patterns were preserved across different mental states, such as NTS, resting before motor imagery (MI, and MI states, even though the spatial distribution of both BCI-illiterate and BCI-literate groups did not differ. From these findings, an effective strategy for pre-screening subjects for BCI illiteracy has been determined, and a performance factor that reflects potential user performance has been proposed using a simple combination of band powers. Our proposed performance factor gave an r = 0.59 (r(2 = 0.34 in a correlation analysis with BCI performance and yielded as much as r = 0.70 (r(2 = 0.50 when seven outliers were rejected during the evaluation of whole data (N = 61, including BCI competition datasets (N = 9. These findings may be directly applicable to online BCI systems.

  8. Anodal transcranial direct current stimulation enhances the effects of motor imagery training in a finger tapping task.

    Saimpont, Arnaud; Mercier, Catherine; Malouin, Francine; Guillot, Aymeric; Collet, Christian; Doyon, Julien; Jackson, Philip L

    2016-01-01

    Motor imagery (MI) training and anodal transcranial direct current stimulation (tDCS) applied over the primary motor cortex can independently improve hand motor function. The main objective of this double-blind, sham-controlled study was to examine whether anodal tDCS over the primary motor cortex could enhance the effects of MI training on the learning of a finger tapping sequence. Thirty-six right-handed young human adults were assigned to one of three groups: (i) who performed MI training combined with anodal tDCS applied over the primary motor cortex; (ii) who performed MI training combined with sham tDCS; and (iii) who received tDCS while reading a book. The MI training consisted of mentally rehearsing an eight-item complex finger sequence for 13 min. Before (Pre-test), immediately after (Post-test 1), and at 90 min after (Post-test 2) MI training, the participants physically repeated the sequence as fast and as accurately as possible. An anova showed that the number of sequences correctly performed significantly increased between Pre-test and Post-test 1 and remained stable at Post-test 2 in the three groups (P strength within the primary motor cortex could have been reinforced by the association of MI training and tDCS compared with MI training alone and tDCS alone. PMID:26540137

  9. Effects of imagery motor training on torque production of ankle plantar flexor muscles

    Zijdewind, Inge; Toering, ST; Bessem, B; van der Laan, O; Diercks, RL

    2003-01-01

    The aim of this study was to investigate in control subjects the effect of imagery training on the torque of plantar-flexor muscles of the ankle. Twenty-nine subjects were allocated to one of three groups that performed either imagery training, low-intensity strength training, or no training (only m

  10. Classifying Single Trail Electroencephalogram Using Gaussian Smoothened Fast Hartley Transform for Brain Computer Interface during Motor Imagery

    V. B. Deepa

    2011-01-01

    Full Text Available Problem statement: Brain-Computer Interface (BCI is a emerging research area which translates the brain signals for any motor related actions into computer understandable signals by capturing the signal, processing the signal and classifying the motor imagery. This area of work finds various applications in neuroprosthetics. Mental activity leads to changes of electrophysiological signals like the Electroencephalogram (EEG or Electrocorticogram (ECoG. Approach: The BCI system detects such changes and transforms it into a control signal which can, for example, be used as to control a electric wheel. In this study the BCI paradigm is tested by our proposed Gaussian smoothened Fast Hartley Transform (GS-FHT which is used to compute the energies of different motor imageries the subject thinks after selecting the required frequencies using band pass filter. Results: We apply this procedure to BCI Competition dataset IVA, a publicly available EEG repository. Conclusion: The evaluations of preprocessed signals showed that the extracted features were interpretable and can lead to high classification accuracy by various mining algorithms.

  11. Dizzy people perform no worse at a motor imagery task requiring whole body mental rotation; a case-control comparison

    Sarah B Wallwork

    2013-06-01

    Full Text Available We wanted to find out whether people who suffer from dizziness take longer than people who do not, to perform a motor imagery task that involves implicit whole body rotation. Our prediction was that people in the ‘dizzy’ group would take longer at a left/right neck rotation judgment task but not a left/right hand judgment task, because actually performing the former, but not the latter, would exacerbate their dizziness. Secondly, we predicted that when dizzy participants responded to neck rotation images, responses would be greatest when images were in the upside-down orientation; an orientation with greatest dizzy-provoking potential. To test this idea, we used a case-control comparison design. One hundred and eighteen participants who suffered from dizziness and 118 age, gender, arm pain and neck pain matched controls took part in the study. Participants undertook two motor imagery tasks; a left/right neck rotation judgment task and a left/right hand judgment task. The tasks were completed using the Recognise program; an on-line reaction time task program. Images of neck rotation were shown in four different orientations; 0°, 90°, 180° and 270°. Participants were asked to respond to each ‘neck’ image identifying it as either ‘right neck rotation’ or a ‘left neck rotation’, or for hands, a right or a left hand. Results showed that participants in the ‘dizzy’ group were slower than controls at both tasks (p= 0.015, but this was not related to task (p= 0.498. Similarly, ‘dizzy’ participants were not proportionally worse at images of different orientations (p= 0.878. Our findings suggest impaired performance in dizzy people, an impairment that may be confined to motor imagery or may extend more generally.

  12. Sources of EEG activity most relevant to performance of brain-computer interface based on motor imagery

    Frolov, A.; Húsek, Dušan; Bobrov, P.; Korshakov, A.V.; Chernikova, L.; Konovalov, R.; Mokienko, O.

    2012-01-01

    Roč. 22, č. 1 (2012), s. 21-37. ISSN 1210-0552 R&D Projects: GA ČR GAP202/10/0262 Grant ostatní: GA MŠk(CZ) ED1.1.00/02.0070 Institutional research plan: CEZ:AV0Z10300504 Keywords : brain-computer interface * independent component analysis * pattern classification * motor imagery * inverse problem * fMRI * EEG Subject RIV: IN - Informatics, Computer Science Impact factor: 0.362, year: 2012

  13. Localizing Sources of Brain Activity Relevant to Motor Imagery Brain-Computer Interface Performance, Using Individual Head Geometry

    Frolov, A.; Húsek, Dušan; Bobrov, P.; Korshakov, A.V.; Chernikova, L.; Konovalov, R.; Mokienko, O.

    Vol. 1. Berlin: Springer, 2012 - (Wang, J.; Yen, G.; Polycarpou, M.), s. 369-378. (Lecture Notes in Computer Science. 7367). ISBN 978-3-642-31345-5. ISSN 0302-9743. [ISNN 2012. International Symposium on Neural Networks /9./. Shenyang (CN), 11.07.2012-14.07.2012] Grant ostatní: GA MŠk(CZ) ED1.1.00/02.0070 Institutional research plan: CEZ:AV0Z10300504 Keywords : BCI * ICA * Bayesian classification * EEG inverse problem * motor imagery * mu rhythm * fMRI Subject RIV: IN - Informatics, Computer Science

  14. Clustering the Sources of EEG Activity during Motor Imagery by Attractor Neural Network with Increasing Activity (ANNIA)

    Bobrov, P.; Frolov, A.; Húsek, Dušan; Snášel, V.

    Cham: Springer, 2014 - (Krömer, P.; Abraham, A.; Snášel, V.), s. 183-191. (Advances in Intelligent Systems and Computing. 303). ISBN 978-3-319-08155-7. ISSN 2194-5357. [IBICA 2014. International Conference on Innovations in Bio-Inspired Computing and Applications /5./. Ostrava (CZ), 23.06.2014-25.06.2014] Grant ostatní: GA MŠk(CZ) ED1.1.00/02.0070; GA MŠk(CZ) EE.2.3.20.0073 Institutional support: RVO:67985807 Keywords : brain computer interface * motor imagery * independent component analysis * attractor neural network with increasing activity Subject RIV: IN - Informatics, Computer Science

  15. Autonomously Propelled Motors for Value-Added Product Synthesis and Purification.

    Srivastava, Sarvesh K; Schmidt, Oliver G

    2016-06-27

    A proof-of-concept design for autonomous, self-propelling motors towards value-added product synthesis and separation is presented. The hybrid motor design consists of two distinct functional blocks. The first, a sodium borohydride (NaBH4 ) granule, serves both as a reaction prerequisite for the reduction of vanillin and also as a localized solid-state fuel in the reaction mixture. The second capping functional block consisting of a graphene-polymer composite serves as a hydrophobic matrix to attract the reaction product vanillyl alcohol (VA), resulting in facile separation of this edible value-added product. These autonomously propelled motors were fabricated at a length scale down to 400 μm, and once introduced in the reaction environment showed rapid bubble-propulsion followed by high-purity separation of the reaction product (VA) by the virtue of the graphene-polymer cap acting as a mesoporous sponge. The concept has excellent potential towards the synthesis/isolation of industrially important compounds, affinity-based product separation, pollutant remediation (such as heavy metal chelation/adsorption), as well as localized fuel-gradients as an alternative to external fuel dependency. PMID:27123788

  16. 基于fNIRS的运动执行与运动想象脑激活模式比较%Comparison of motor execution and motor imagery brain activation patterns:A fNIRS Study

    白学军; 张琪涵; 章鹏; 周菘; 刘颖; 宋星; 彭国慧

    2016-01-01

    It is widely believed that activity in the primary motor cortex relates only to motor execution. However, the extent to which similar activity occurs when imagining motor movements remains to be determined and, while some researchers report activity in the primary motor cortex during both motor execution and motor imagery tasks (e.g.Solodkin et al., 2004; Sharma et al., 2008), others report no effects of motor imagery (e.g., Binkofski et al., 2000; Hanakawa et al., 2003; Hétu et al., 2013). It is still unknown whether brain activation patterns of motor execution and motor imagery are similar, and whether both tasks activate the primary motor cortex. In addition, it is also unclear about the effect of imagination intensity on the primary motor cortex (this effect has been well established in motor execution tasks). Accordingly, the present research investigated the relationship between the intensity of real and imagined exercise on cortical activity using functional near-infrared spectroscopy (fNIRS), especially in the primary motor cortex. A preliminary assessment used 10 participants (5 male, 5 female), who did not take part in the main experiment, to establish an appropriate level of exercise intensity. For the main experiment, 30 participants (15 male, 15 female) with high imagination ability were selected using the Motor Imagery Questionnaire (Revised). These participants performed a motor execution task in which they actually lifted dumbbells under two levels of exercise intensity (males, 4 pounds and 8 pounds; females, 2 pounds and 4 pounds) and an imagery version of this task in which they imagined lifting dumbbells of these weights. The fNIRS was used to measure cortical changes in oxygen level during the performance of the two tasks. Finally, on completion of the imagery task, the “motor imagery self-assessment questionnaire” was administered to assess the quality of the participants’ imagination. All participants reported that they could imagine

  17. The effect of leisure activity golf practice on motor imagery: an fMRI study in middle adulthood.

    Bezzola, Ladina; Mérillat, Susan; Jäncke, Lutz

    2012-01-01

    Much is known about practice-induced plasticity of the motor system. But it is not clear how a physical training influences the mental rehearsal of the practiced task and its associated hemodynamic responses. In the present longitudinal study with two measurement time-points, we used the method of functional magnetic resonance imaging (fMRI) and a motor imagery task, in order to explore the dynamic neuro-functional changes induced by a highly complex physical training. The 11 golf novices between the age of 40 and 60 years practiced the motor training as leisure activity. Additionally, data from an age and sex-matched control group without golf training was collected. As a main result, we demonstrate that changes between the two measurement time-points were only found in the golf novice group. The golf novices showed a decrease in hemodynamic responses during the mental rehearsal of the golf swing in non-primary motor areas after the 40 h of golf practice. Thus, the results indicate that a complex physical leisure activity induces functional neuroplasticity in the seldom studied population of middle-aged adults, and that this effect is evident during mental rehearsal of the practiced task. This finding supports the idea that (a) a skill improvement is associated with a modified activation pattern in the associated neuronal network that can be identified during mental rehearsal of the practiced task, and that (b) a strict training protocol is not necessary to induce functional neuroplasticity. PMID:22479243

  18. Action Verbs and the Primary Motor Cortex: A Comparative TMS Study of Silent Reading, Frequency Judgments, and Motor Imagery

    Tomasino, Barbara; Fink, Gereon R.; Sparing, Roland; Dafotakis, Manuel; Weiss, Peter H.

    2008-01-01

    Single pulse transcranial magnetic stimulation (TMS) was applied to the hand area of the left primary motor cortex or, as a control, to the vertex (STIMULATION: TMS[subscript M1] vs. TMS[subscript vertex]) while right-handed volunteers silently read verbs related to hand actions. We examined three different tasks and time points for stimulation…

  19. Graded motor imagery is effective for long-standing complex regional pain syndrome: a randomised controlled trial.

    Moseley, G L

    2004-03-01

    Complex regional pain syndrome type 1 (CRPS1) involves cortical abnormalities similar to those observed in phantom pain and after stroke. In those groups, treatment is aimed at activation of cortical networks that subserve the affected limb, for example mirror therapy. However, mirror therapy is not effective for chronic CRPS1, possibly because movement of the limb evokes intolerable pain. It was hypothesised that preceding mirror therapy with activation of cortical networks without limb movement would reduce pain and swelling in patients with chronic CRPS1. Thirteen chronic CRPS1 patients were randomly allocated to a motor imagery program (MIP) or to ongoing management. The MIP consisted of two weeks each of a hand laterality recognition task, imagined hand movements and mirror therapy. After 12 weeks, the control group was crossed-over to MIP. There was a main effect of treatment group (F(1, 11) = 57, P limb movement is effective for CRPS1 and support the involvement of cortical abnormalities in the development of this disorder. Although the mechanisms of effect of the MIP are not clear, possible explanations are sequential activation of cortical pre-motor and motor networks, or sustained and focussed attention on the affected limb, or both. PMID:15109523

  20. Using Fractal and Local Binary Pattern Features for Classification of ECOG Motor Imagery Tasks Obtained from the Right Brain Hemisphere.

    Xu, Fangzhou; Zhou, Weidong; Zhen, Yilin; Yuan, Qi; Wu, Qi

    2016-09-01

    The feature extraction and classification of brain signal is very significant in brain-computer interface (BCI). In this study, we describe an algorithm for motor imagery (MI) classification of electrocorticogram (ECoG)-based BCI. The proposed approach employs multi-resolution fractal measures and local binary pattern (LBP) operators to form a combined feature for characterizing an ECoG epoch recording from the right hemisphere of the brain. A classifier is trained by using the gradient boosting in conjunction with ordinary least squares (OLS) method. The fractal intercept, lacunarity and LBP features are extracted to classify imagined movements of either the left small finger or the tongue. Experimental results on dataset I of BCI competition III demonstrate the superior performance of our method. The cross-validation accuracy and accuracy is 90.6% and 95%, respectively. Furthermore, the low computational burden of this method makes it a promising candidate for real-time BCI systems. PMID:27255798

  1. Use of video observation and motor imagery on jumping performance in national rhythmic gymnastics athletes.

    Battaglia, Claudia; D'Artibale, Emanuele; Fiorilli, Giovanni; Piazza, Marina; Tsopani, Despina; Giombini, Arrigo; Calcagno, Giuseppe; di Cagno, Alessandra

    2014-12-01

    The aim of this study was to evaluate whether a mental training protocol could improve gymnastic jumping performance. Seventy-two rhythmic gymnasts were randomly divided into an experimental and control group. At baseline, experimental group completed the Movement Imagery Questionnaire Revised (MIQ-R) to assess the gymnast ability to generate movement imagery. A repeated measures design was used to compare two different types of training aimed at improving jumping performance: (a) video observation and PETTLEP mental training associated with physical practice, for the experimental group, and (b) physical practice alone for the control group. Before and after six weeks of training, their jumping performance was measured using the Hopping Test (HT), Drop Jump (DJ), and Counter Movement Jump (CMJ). Results revealed differences between jumping parameters F(1,71)=11.957; p<.01, and between groups F(1,71)=10.620; p<.01. In the experimental group there were significant correlations between imagery ability and the post-training Flight Time of the HT, r(34)=-.295, p<.05 and the DJ, r(34)=-.297, p<.05. The application of the protocol described herein was shown to improve jumping performance, thereby preserving the elite athlete's energy for other tasks. PMID:25457420

  2. EEG Event-Related Desynchronization of patients with stroke during motor imagery of hand movement

    Tabernig, Carolina B.; Carrere, Lucía C.; Lopez, Camila A.; Ballario, Carlos

    2016-04-01

    Brain Computer Interfaces (BCI) can be used for therapeutic purposes to improve voluntary motor control that has been affected post stroke. For this purpose, desynchronization of sensorimotor rhythms of the electroencephalographic signal (EEG) can be used. But it is necessary to study what happens in the affected motor cortex of this people. In this article, we analyse EEG recordings of hemiplegic stroke patients to determine if it is possible to detect desynchronization in the affected motor cortex during the imagination of movements of the affected hand. Six patients were included in the study; four evidenced desynchronization in the affected hemisphere, one of them showed no results and the EEG recordings of the last patient presented high noise level. These results suggest that we could use the desynchronization of sensorimotor rhythms of the EEG signal as a BCI paradigm in a rehabilitation programme.

  3. Structural and functional correlates of motor imagery BCI performance: Insights from the patterns of fronto-parietal attention network.

    Zhang, Tao; Liu, Tiejun; Li, Fali; Li, Mengchen; Liu, Dongbo; Zhang, Rui; He, Hui; Li, Peiyang; Gong, Jinnan; Luo, Cheng; Yao, Dezhong; Xu, Peng

    2016-07-01

    Motor imagery (MI)-based brain-computer interfaces (BCIs) have been widely used for rehabilitation of motor abilities and prosthesis control for patients with motor impairments. However, MI-BCI performance exhibits a wide variability across subjects, and the underlying neural mechanism remains unclear. Several studies have demonstrated that both the fronto-parietal attention network (FPAN) and MI are involved in high-level cognitive processes that are crucial for the control of BCIs. Therefore, we hypothesized that the FPAN may play an important role in MI-BCI performance. In our study, we recorded multi-modal datasets consisting of MI electroencephalography (EEG) signals, T1-weighted structural and resting-state functional MRI data for each subject. MI-BCI performance was evaluated using the common spatial pattern to extract the MI features from EEG signals. One cortical structural feature (cortical thickness (CT)) and two measurements (degree centrality (DC) and eigenvector centrality (EC)) of node centrality were derived from the structural and functional MRI data, respectively. Based on the information extracted from the EEG and MRI, a correlation analysis was used to elucidate the relationships between the FPAN and MI-BCI performance. Our results show that the DC of the right ventral intraparietal sulcus, the EC and CT of the left inferior parietal lobe, and the CT of the right dorsolateral prefrontal cortex were significantly associated with MI-BCI performance. Moreover, the receiver operating characteristic analysis and machine learning classification revealed that the EC and CT of the left IPL could effectively predict the low-aptitude BCI users from the high-aptitude BCI users with 83.3% accuracy. Those findings consistently reveal that the individuals who have efficient FPAN would perform better on MI-BCI. Our findings may deepen the understanding of individual variability in MI-BCI performance, and also may provide a new biomarker to predict individual

  4. Feature Selection Strategy for Classification of Single-Trial EEG Elicited by Motor Imagery

    Prasad, Swati; Tan, Zheng-Hua; Prasad, Ramjee;

    2011-01-01

    Brain-Computer Interface (BCI) provides new means of communication for people with motor disabilities by utilizing electroencephalographic activity. Selection of features from Electroencephalogram (EEG) signals for classification plays a key part in the development of BCI systems. In this paper, ...... system that uses wavelet coefficients as features and support vector machine (SVM) as classifier...

  5. Modulation of hand motor-related area during motor imagery and motor execution before and after middle 2/5 of the MS6 line scalp acupuncture stimulation: An fMRI study.

    Romeo, Zanardi; Marta, Maieron; Barbara, Tomasino

    2016-03-01

    Scalp acupuncture (SA) combines the concept of cerebral cortex organization with the principles of acupuncture. The SA stimulates sections of the cerebral cortex. We studied the functional modulation of the left hand sensorimotor area induced by SA in order to investigate the specificity of the SA-related functional effects of the middle 2/5 of the MS6 line of the left side, which corresponds to the upper limb motor segment of the primary motor area. To this purpose, we compared the pre- and post-SA functional activation patterns during an implicit motor imagery task (handedness decision in which participants simulated rotational hand movements) and an explicit manual motor execution task. Feet and mouth movements, and the fMRI changes in their respective representations were used as control conditions. Only SA on the hand area of the left side (as compared to the mouth and the foot representations which were used as control conditions) exerted a release effect on the right hand area. In addition, an increased activation of the superior parietal lobe was seen, which is involved in movement control and planning. Taken together, these preliminary findings may shed light on the SA effects and confirm a prolonged effect of SA even after cessation of needling stimulation. PMID:26799679

  6. Comparison of EEG-features and classification methods for motor imagery in patients with disorders of consciousness.

    Yvonne Höller

    Full Text Available Current research aims at identifying voluntary brain activation in patients who are behaviorally diagnosed as being unconscious, but are able to perform commands by modulating their brain activity patterns. This involves machine learning techniques and feature extraction methods such as applied in brain computer interfaces. In this study, we try to answer the question if features/classification methods which show advantages in healthy participants are also accurate when applied to data of patients with disorders of consciousness. A sample of healthy participants (N = 22, patients in a minimally conscious state (MCS; N = 5, and with unresponsive wakefulness syndrome (UWS; N = 9 was examined with a motor imagery task which involved imagery of moving both hands and an instruction to hold both hands firm. We extracted a set of 20 features from the electroencephalogram and used linear discriminant analysis, k-nearest neighbor classification, and support vector machines (SVM as classification methods. In healthy participants, the best classification accuracies were seen with coherences (mean = .79; range = .53-.94 and power spectra (mean = .69; range = .40-.85. The coherence patterns in healthy participants did not match the expectation of central modulated [Formula: see text]-rhythm. Instead, coherence involved mainly frontal regions. In healthy participants, the best classification tool was SVM. Five patients had at least one feature-classifier outcome with p[Formula: see text]0.05 (none of which were coherence or power spectra, though none remained significant after false-discovery rate correction for multiple comparisons. The present work suggests the use of coherences in patients with disorders of consciousness because they show high reliability among healthy subjects and patient groups. However, feature extraction and classification is a challenging task in unresponsive patients because there is no ground truth to validate the results.

  7. Comparison of EEG-features and classification methods for motor imagery in patients with disorders of consciousness.

    Höller, Yvonne; Bergmann, Jürgen; Thomschewski, Aljoscha; Kronbichler, Martin; Höller, Peter; Crone, Julia S; Schmid, Elisabeth V; Butz, Kevin; Nardone, Raffaele; Trinka, Eugen

    2013-01-01

    Current research aims at identifying voluntary brain activation in patients who are behaviorally diagnosed as being unconscious, but are able to perform commands by modulating their brain activity patterns. This involves machine learning techniques and feature extraction methods such as applied in brain computer interfaces. In this study, we try to answer the question if features/classification methods which show advantages in healthy participants are also accurate when applied to data of patients with disorders of consciousness. A sample of healthy participants (N = 22), patients in a minimally conscious state (MCS; N = 5), and with unresponsive wakefulness syndrome (UWS; N = 9) was examined with a motor imagery task which involved imagery of moving both hands and an instruction to hold both hands firm. We extracted a set of 20 features from the electroencephalogram and used linear discriminant analysis, k-nearest neighbor classification, and support vector machines (SVM) as classification methods. In healthy participants, the best classification accuracies were seen with coherences (mean = .79; range = .53-.94) and power spectra (mean = .69; range = .40-.85). The coherence patterns in healthy participants did not match the expectation of central modulated [Formula: see text]-rhythm. Instead, coherence involved mainly frontal regions. In healthy participants, the best classification tool was SVM. Five patients had at least one feature-classifier outcome with p[Formula: see text]0.05 (none of which were coherence or power spectra), though none remained significant after false-discovery rate correction for multiple comparisons. The present work suggests the use of coherences in patients with disorders of consciousness because they show high reliability among healthy subjects and patient groups. However, feature extraction and classification is a challenging task in unresponsive patients because there is no ground truth to validate the results. PMID:24282545

  8. Brain-Computer Interface Based on Motor Imagery: the Most Relevant Sources of Electrical Brain Activity

    Frolov, A. A.; Húsek, Dušan; Snášel, V.; Bobrov, P.; Mokienko, O.; Tintěra, J.; Rydlo, J.

    Cham: Springer, 2014 - (Snášel, V.; Krömer, P.; Köppen, M.; Schaefer, G.), s. 153-163. (Advances in Intelligent Systems and Computing. 223). ISBN 978-3-319-00929-2. ISSN 2194-5357. [Online World Conference on Soft Computing in Industrial Applications /17./. Anywhere on Earth, 10.12.2012-21.12.2012)] Grant ostatní: GA MŠk(CZ) ED1.1.00/02.0070; GA MŠk(CZ) EE.2.3.20.0073 Institutional support: RVO:67985807 Keywords : Image and Signal Processing * Brain-Computer Interface * Independent Component Analysis * EEG Pattern Classification * fMRI * Motor Image ry * Pattern Recognition Subject RIV: IN - Informatics, Computer Science http://dap.vsb.cz/wsc17conf/brain-computer-interface-based-on-motor- image ry---the-most-relevant-sources-of-electrical-brain-activity

  9. Age-specific activation of cerebral areas in motor imagery - a fMRI study

    The objectives of this study were to study the age-specific activation patterns of cerebral areas during motor execution (ME) and motor imaging (MI) of the upper extremities and to discuss the age-related neural mechanisms associated with ME or MI. The functional magnetic resonance imaging technique was used to monitor the pattern and intensity of brain activation during the ME and MI of the upper extremities in 20 elderly (>50 years) and 19 young healthy subjects (<25 years). No major differences were identified regarding the activated brain areas during ME or MI between the two groups; however, a minor difference was noted. The intensity of the activated brain area during ME was stronger in the older group than in the younger group, while the results with MI were the opposite. The posterior central gyrus and supplementary motor area during MI were more active in the younger group than in the older group. The putamen, lingual, and so on demonstrated stronger activation during dominant hand MI in the older group. The results of this study revealed that the brain structure was altered and that neuronal activity was attenuated with age, and the cerebral cortex and subcortical tissues were found to be over-activated to achieve the same level of ME and MI, indicating that the activating effects of the left hemisphere enhanced with age, whereas the inhibitory effects declined during ME, and activation of the right hemisphere became more difficult during MI. (orig.)

  10. Age-specific activation of cerebral areas in motor imagery - a fMRI study

    Wang, Li [Chongqing University, Key Laboratory of Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing (China); Third Military Medical University, Department of Medical Image, College of Biomedical Engineering, Chongqing (China); Qiu, Mingguo; Zhang, Jingna; Zhang, Ye; Sang, Linqiong [Third Military Medical University, Department of Medical Image, College of Biomedical Engineering, Chongqing (China); Liu, Chen; Yang, Jun [Third Military Medical University, Department of Radiology, Southwest Hospital, Chongqing (China); Yan, Rubing [Third Military Medical University, Department of Rehabilitation, Southwest Hospital, Chongqing (China); Zheng, Xiaolin [Chongqing University, Key Laboratory of Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing (China)

    2014-04-15

    The objectives of this study were to study the age-specific activation patterns of cerebral areas during motor execution (ME) and motor imaging (MI) of the upper extremities and to discuss the age-related neural mechanisms associated with ME or MI. The functional magnetic resonance imaging technique was used to monitor the pattern and intensity of brain activation during the ME and MI of the upper extremities in 20 elderly (>50 years) and 19 young healthy subjects (<25 years). No major differences were identified regarding the activated brain areas during ME or MI between the two groups; however, a minor difference was noted. The intensity of the activated brain area during ME was stronger in the older group than in the younger group, while the results with MI were the opposite. The posterior central gyrus and supplementary motor area during MI were more active in the younger group than in the older group. The putamen, lingual, and so on demonstrated stronger activation during dominant hand MI in the older group. The results of this study revealed that the brain structure was altered and that neuronal activity was attenuated with age, and the cerebral cortex and subcortical tissues were found to be over-activated to achieve the same level of ME and MI, indicating that the activating effects of the left hemisphere enhanced with age, whereas the inhibitory effects declined during ME, and activation of the right hemisphere became more difficult during MI. (orig.)

  11. A hybrid BCI based on EEG and fNIRS signals improves the performance of decoding motor imagery of both force and speed of hand clenching

    Yin, Xuxian; Xu, Baolei; Jiang, Changhao; Fu, Yunfa; Wang, Zhidong; Li, Hongyi; Shi, Gang

    2015-06-01

    Objective. In order to increase the number of states classified by a brain-computer interface (BCI), we utilized a motor imagery task where subjects imagined both force and speed of hand clenching. Approach. The BCI utilized simultaneously recorded electroencephalographic (EEG) and functional near-infrared spectroscopy (fNIRS) signals. The time-phase-frequency feature was extracted from EEG, whereas the HbD [the difference of oxy-hemoglobin (HbO) and deoxy-hemoglobin (Hb)] feature was used to improve the classification accuracy of fNIRS. The EEG and fNIRS features were combined and optimized using the joint mutual information (JMI) feature selection criterion; then the extracted features were classified with the extreme learning machines (ELMs). Main results. In this study, the averaged classification accuracy of EEG signals achieved by the time-phase-frequency feature improved by 7%, to 18%, more than the single-type feature, and improved by 15% more than common spatial pattern (CSP) feature. The HbD feature of fNIRS signals improved the accuracy by 1%, to 4%, more than Hb, HbO, or HbT (total hemoglobin). The EEG-fNIRS feature for decoding motor imagery of both force and speed of hand clenching achieved an accuracy of 89% ± 2%, and improved the accuracy by 1% to 5% more than the sole EEG or fNIRS feature. Significance. Our novel motor imagery paradigm improves BCI performance by increasing the number of extracted commands. Both the time-phase-frequency and the HbD feature improve the classification accuracy of EEG and fNIRS signals, respectively, and the hybrid EEG-fNIRS technique achieves a higher decoding accuracy for two-class motor imagery, which may provide the framework for future multi-modal online BCI systems.

  12. The Changes in the Hemodynamic Activity of the Brain during Motor Imagery Training with the Use of Brain-Computer Interface1

    Frolov, A. A.; Húsek, Dušan; Silchenko, A.V.; Tintěra, J.; Rydlo, J.

    2016-01-01

    Roč. 42, č. 1 (2016), s. 1-12. ISSN 0362-1197 R&D Projects: GA MŠk ED1.1.00/02.0070 Grant ostatní: GA MŠk(CZ) EE.2.3.20.0073 Institutional support: RVO:67985807 Keywords : brain-computer interface * motor imagery * hemodynamic activity * brain plasticity * functional MRI Subject RIV: IN - Informatics, Computer Science

  13. Towards increasing the number of commands in a hybrid brain-computer interface with combination of gaze and motor imagery.

    Meena, Yogesh Kumar; Cecotti, Hubert; KongFatt Wong-Lin; Prasad, Girijesh

    2015-08-01

    Non-invasive brain-computer interface (BCI) provides a novel means of communication. This can be achieved by measuring electroencephalogram (EEG) signal over the sensory motor cortex of a person performing motor imagery (MI) tasks. However, the performance of BCI remains currently too low to be of wide practical use. A hybrid BCI system could improve the performance by combining two or more modalities such as eye tracking, and the detection of brain activity responses. In this paper, first, we propose a simultaneous hybrid BCI that combines an event-related de-synchronization (ERD) BCI and an eye tracker. Second, we aim to further improve performance by increasing the number of commands (i.e., the number of choices accessible to the user). In particular, we show a significant improvement in performance for a simultaneous gaze-MI system using a total of eight commands. The experimental task requires subjects to search for spatially located items using gaze, and select an item using MI signals. This experimental task studied visuomotor compatible and incompatible conditions. As incorporating incompatible conditions between gaze direction and MI can increase the number of choices in the hybrid BCI, our experimental task includes single-trial detection for average, compatible and incompatible conditions, using seven different classification methods. The mean accuracy for MI, and the information transfer rate (ITR) for the compatible condition is found to be higher than the average and the incompatible conditions. The results suggest that gaze-MI hybrid BCI systems can increase the number of commands, and the location of the items should be taken into account for designing the system. PMID:26736310

  14. A novel Morse code-inspired method for multiclass motor imagery brain-computer interface (BCI) design.

    Jiang, Jun; Zhou, Zongtan; Yin, Erwei; Yu, Yang; Liu, Yadong; Hu, Dewen

    2015-11-01

    Motor imagery (MI)-based brain-computer interfaces (BCIs) allow disabled individuals to control external devices voluntarily, helping us to restore lost motor functions. However, the number of control commands available in MI-based BCIs remains limited, limiting the usability of BCI systems in control applications involving multiple degrees of freedom (DOF), such as control of a robot arm. To address this problem, we developed a novel Morse code-inspired method for MI-based BCI design to increase the number of output commands. Using this method, brain activities are modulated by sequences of MI (sMI) tasks, which are constructed by alternately imagining movements of the left or right hand or no motion. The codes of the sMI task was detected from EEG signals and mapped to special commands. According to permutation theory, an sMI task with N-length allows 2 × (2(N)-1) possible commands with the left and right MI tasks under self-paced conditions. To verify its feasibility, the new method was used to construct a six-class BCI system to control the arm of a humanoid robot. Four subjects participated in our experiment and the averaged accuracy of the six-class sMI tasks was 89.4%. The Cohen's kappa coefficient and the throughput of our BCI paradigm are 0.88 ± 0.060 and 23.5bits per minute (bpm), respectively. Furthermore, all of the subjects could operate an actual three-joint robot arm to grasp an object in around 49.1s using our approach. These promising results suggest that the Morse code-inspired method could be used in the design of BCIs for multi-DOF control. PMID:26340647

  15. Moving without moving: immediate management following lumbar spine surgery using a graded motor imagery approach: a case report.

    Louw, Adriaan; Schmidt, Stephen G; Louw, Colleen; Puentedura, Emilio J

    2015-10-01

    Representational body maps are dynamically maintained in the brain and negatively influenced by neglect, decreased movement and pain. Graded motor imagery (GMI) utilizing various tactile and cognitive processes has shown efficacy in decreasing pain, disability and movement restrictions in musculoskeletal pain. Limited information is known about the cortical changes patients undergo during lumbar surgery (LS), let alone the therapeutic effect of GMI for LS. A 56-year-old patient underwent LS for low back pain, leg pain and progressive neurological deficit. Twenty-four hours prior to and 48 h after LS various psychometric, physical movement and tactile acuity measurements were recorded. Apart from predictable postoperative increases in pain, fear-avoidance, disability and movement-restrictions, pressure pain thresholds (PPT), two-point discrimination (TPD) and tactile acuity was greatly reduced. The patient underwent six physiotherapy (PT) treatments receiving a GMI program aimed at restoring the PPT, TPD and tactile acuity. The results revealed that GMI techniques applied to a patient immediately after LS caused marked improvements in movement (flexion average improvement/session 3.3 cm; straight leg raise average 8.3°/session) and an immediate hypoalgesic effect. GMI may provide PT with a non-threatening therapeutic treatment for the acute LS patient and establish a new role for PT in acute LS patients. PMID:26395828

  16. Single-trial classification of motor imagery differing in task complexity: a functional near-infrared spectroscopy study

    Wolf Martin

    2011-06-01

    Full Text Available Abstract Background For brain computer interfaces (BCIs, which may be valuable in neurorehabilitation, brain signals derived from mental activation can be monitored by non-invasive methods, such as functional near-infrared spectroscopy (fNIRS. Single-trial classification is important for this purpose and this was the aim of the presented study. In particular, we aimed to investigate a combined approach: 1 offline single-trial classification of brain signals derived from a novel wireless fNIRS instrument; 2 to use motor imagery (MI as mental task thereby discriminating between MI signals in response to different tasks complexities, i.e. simple and complex MI tasks. Methods 12 subjects were asked to imagine either a simple finger-tapping task using their right thumb or a complex sequential finger-tapping task using all fingers of their right hand. fNIRS was recorded over secondary motor areas of the contralateral hemisphere. Using Fisher's linear discriminant analysis (FLDA and cross validation, we selected for each subject a best-performing feature combination consisting of 1 one out of three channel, 2 an analysis time interval ranging from 5-15 s after stimulation onset and 3 up to four Δ[O2Hb] signal features (Δ[O2Hb] mean signal amplitudes, variance, skewness and kurtosis. Results The results of our single-trial classification showed that using the simple combination set of channels, time intervals and up to four Δ[O2Hb] signal features comprising Δ[O2Hb] mean signal amplitudes, variance, skewness and kurtosis, it was possible to discriminate single-trials of MI tasks differing in complexity, i.e. simple versus complex tasks (inter-task paired t-test p ≤ 0.001, over secondary motor areas with an average classification accuracy of 81%. Conclusions Although the classification accuracies look promising they are nevertheless subject of considerable subject-to-subject variability. In the discussion we address each of these aspects, their

  17. Adding effect of current displacement and magnetic circuit saturation in an asynchronous motor mathematical model

    I.A. Tsodik

    2014-04-01

    Full Text Available A methodology of an asynchronous motor mathematical model synthesis is described. Experiments are suggested to be conducted in the following sequence. Geometrical models are first built in AutoCAD, then imported to Comsol Multiphysics, and further processed in Matlab with computation of coefficients and dependences applied in the asynchronous motor mathematical model.

  18. Long-Lasting Cortical Reorganization as the Result of Motor Imagery of Throwing a Ball in a Virtual Tennis Court

    Cebolla, Ana M.; Petieau, Mathieu; Cevallos, Carlos; Leroy, Axelle; Dan, Bernard; Cheron, Guy

    2015-01-01

    In order to characterize the neural signature of a motor imagery (MI) task, the present study investigates for the first time the oscillation characteristics including both of the time-frequency measurements, event related spectral perturbation and intertrial coherence (ITC) underlying the variations in the temporal measurements (event related potentials, ERP) directly related to a MI task. We hypothesize that significant variations in both of the time-frequency measurements underlie the specific changes in the ERP directly related to MI. For the MI task, we chose a simple everyday task (throwing a tennis ball), that does not require any particular motor expertise, set within the controlled virtual reality scenario of a tennis court. When compared to the rest condition a consistent, long-lasting negative fronto-central ERP wave was accompanied by significant changes in both time frequency measurements suggesting long-lasting cortical activity reorganization. The ERP wave was characterized by two peaks at about 300 ms (N300) and 1000 ms (N1000). The N300 component was centrally localized on the scalp and was accompanied by significant phase consistency in the delta brain rhythms in the contralateral central scalp areas. The N1000 component spread wider centrally and was accompanied by a significant power decrease (or event related desynchronization) in low beta brain rhythms localized in fronto-precentral and parieto-occipital scalp areas and also by a significant power increase (or event related synchronization) in theta brain rhythms spreading fronto-centrally. During the transition from N300 to N1000, a contralateral alpha (mu) as well as post-central and parieto-theta rhythms occurred. The visual representation of movement formed in the minds of participants might underlie a top-down process from the fronto-central areas which is reflected by the amplitude changes observed in the fronto-central ERPs and by the significant phase synchrony in contralateral fronto

  19. A novel calibration and task guidance framework for motor imagery BCI via a tendon vibration induced sensation with kinesthesia illusion

    Yao, Lin; Meng, Jianjun; Sheng, Xinjun; Zhang, Dingguo; Zhu, Xiangyang

    2015-02-01

    Objective. Lack of efficient calibration and task guidance in motor imagery (MI) based brain-computer interface (BCI) would result in the failure of communication or control, especially in patients, such as a stroke with motor impairment and intact sensation, locked-in state amyotrophic lateral sclerosis, in which the sources of data for calibration may worsen the subsequent decoding. In addition, enhancing the proprioceptive experience in MI might improve the BCI performance. Approach. In this work, we propose a new calibrating and task guidance methodology to further improve the MI BCI, exploiting the afferent nerve system through tendon vibration stimulation to induce a sensation with kinesthesia illusion. A total of 30 subjects’ experiments were carried out, and randomly divided into a control group (control-group) and calibration and task guidance group (CTG-group). Main results. Online experiments have shown that MI could be decoded by classifier calibrated solely using sensation data, with 8 of the 15 subjects in the CTG-Group above 80%, 3 above 95% and all above 65%. Offline chronological cross-validation analysis shows that it has reached a comparable performance with the traditional calibration method (F(1,14)=0.14,P=0.7176). In addition, the discrimination accuracy of MI in the CTG-Group is significantly 12.17% higher on average than that in the control-group (unpaired-T test, P = 0.0086), and illusory sensation indicates no significant difference (unpaired-T test, p = 0.3412). The finding of the existed similarity of the discriminative brain patterns and grand averaged ERD/ERS between imagined movement (actively induced) and illusory movement (passively evoked) also validates the proposed calibration and task guidance framework. Significance. The cognitive complexity of the illusory sensation task is much lower and more objective than that of MI. In addition, subjects’ kinesthetic experience mentally simulated during the MI task might be enhanced by

  20. Imagery : correlação entre o motor imagery e as habilidades técnicas no basquetebol, em escalões de cadetes e juniores B.

    Silva, Luís Miguel Correia da

    2015-01-01

    Dissertação apresentada à Escola Superior de Educação do Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Atividade Física. A presente investigação tem como principal propósito verificar se existe correlação entre o imagery e as habilidades técnicas do basquetebol, para os gestos técnicos do deslizamento defensivo, drible, passe e lançamento. Pretende também contribuir para a compreensão do conceito de imagery, podendo auxi...

  1. Simulation of added inductive coil influence onto the digital servo system with DC motor

    Aleksandar B. Viličić

    2011-10-01

    Full Text Available This paper describes a simulation of a real electrical servo drive with a digital equalizer. The whole system is simulated in the simulation toolkit of the LabView package. Real transfer functions are simulated (the transfer functions of the motor and the current and angular velocity gauges, as well as the nonlinearities of the motor and the gears. Clasical mathematical methods for modeling servosistems are used. The method for determining transfer function parameters is also used. The influence of neglecting the electrical time constant is analyzed.

  2. 普拉提运动想象的脑电功率谱分析%Power spectral analysis of EEG during Pilates motor imagery

    孙红敏; 边志杰; 崔冬; 李小俚

    2012-01-01

    Neural plasticity and movement therapy techniques have been widely used in brain rehabilitation of functional disorders, but still lack of scientific basis. Aiming at this problem, the EEG power spectral of Pilates trained college students in resting and motor imagery states ias analysed. Compared with the resting state, the Alpha peak frequency was significantly increased among the whole brain, and the Beta peak frequency is increased among the forehead and fronto-central area in the Pilates motor imagery. The statistical results show that the connection among the brain neural network can be improved, thus the function of specific brain areas can be affected by Pilates motor imagery. A guide has been provided for the promotion of Pilates exercise and the use of the Pilates motor imagery in the disease rehabilitation field in the future.%神经可塑性技术和运动疗法已经在大脑功能障碍疾病的康复中得到了广泛应用,但仍然缺乏科学依据.针对此问题,本文对受过普拉提训练的大学生在静息和运动想象过程中脑电功率谱进行分析.结果发现与静息状态相比,普拉提运动想象会引起整个脑区的Alpha主峰频率显著增加,前额和额中央区的Beta主峰频率显著增加.该研究统计结果表明普拉提运动确实能够改善大脑神经网络之间的连接,进而影响特定脑区的功能,这可能为将来普拉提运动的推广和将普拉提运动想象应用于脑功能疾病康复领域提供了参考依据.

  3. Performance evaluation of a motor-imagery-based EEG-Brain computer interface using a combined cue with heterogeneous training data in BCI-Naive subjects

    Lee Youngbum

    2011-10-01

    Full Text Available Abstract Background The subjects in EEG-Brain computer interface (BCI system experience difficulties when attempting to obtain the consistent performance of the actual movement by motor imagery alone. It is necessary to find the optimal conditions and stimuli combinations that affect the performance factors of the EEG-BCI system to guarantee equipment safety and trust through the performance evaluation of using motor imagery characteristics that can be utilized in the EEG-BCI testing environment. Methods The experiment was carried out with 10 experienced subjects and 32 naive subjects on an EEG-BCI system. There were 3 experiments: The experienced homogeneous experiment, the naive homogeneous experiment and the naive heterogeneous experiment. Each experiment was compared in terms of the six audio-visual cue combinations and consisted of 50 trials. The EEG data was classified using the least square linear classifier in case of the naive subjects through the common spatial pattern filter. The accuracy was calculated using the training and test data set. The p-value of the accuracy was obtained through the statistical significance test. Results In the case in which a naive subject was trained by a heterogeneous combined cue and tested by a visual cue, the result was not only the highest accuracy (p Conclusions We propose the use of this measuring methodology of a heterogeneous combined cue for training data and a visual cue for test data by the typical EEG-BCI algorithm on the EEG-BCI system to achieve effectiveness in terms of consistence, stability, cost, time, and resources management without the need for a trial and error process.

  4. Windscreen wiper fluid without added screenwash in motor vehicles: a newly identified risk factor for Legionnaires' disease.

    Wallensten, Anders; Oliver, Isabel; Ricketts, Katherine; Kafatos, George; Stuart, James M; Joseph, Carol

    2010-09-01

    A source of infection is rarely identified for sporadic cases of Legionnaires' disease. We found that professional drivers are five times more commonly represented among community acquired sporadic cases in England and Wales than expected. We therefore investigated possible risk exposures in relation to driving or spending time in a motor vehicle. A case control study including all surviving community acquired sporadic cases in England and Wales with onset between 12 July 2008 and 9 March 2009 was carried out. Cases were contacted by phone and controls were consecutively recruited by sequential digital dialling matched by area code, sex and age group. Those who consented were sent a questionnaire asking questions on driving habits, potential sources in vehicles and known risk factors. The results were analysed using logistic regression. 75 cases and 67 controls were included in the study. Multivariable analysis identified two exposures linked to vehicle use associated with an increased risk of Legionnaires' disease: Driving through industrial areas (OR 7.2, 95%CI 1.5-33.7) and driving or being a passenger in a vehicle with windscreen wiper fluid not containing added screenwash (OR 47.2, 95%CI 3.7-603.6). Not adding screenwash to windscreen wiper fluid is a previously unidentified risk factor and appears to be strongly associated with community acquired sporadic cases of Legionnaires' disease. We estimated that around 20% of community acquired sporadic cases could be attributed to this exposure. A simple recommendation to use screenwash may mitigate transmission of Legionella bacteria to drivers and passengers. PMID:20532623

  5. Motor imagery-induced EEG patterns in individuals with spinal cord injury and their impact on brain-computer interface accuracy

    Müller-Putz, G. R.; Daly, I.; Kaiser, V.

    2014-06-01

    Objective. Assimilating the diagnosis complete spinal cord injury (SCI) takes time and is not easy, as patients know that there is no ‘cure' at the present time. Brain-computer interfaces (BCIs) can facilitate daily living. However, inter-subject variability demands measurements with potential user groups and an understanding of how they differ to healthy users BCIs are more commonly tested with. Thus, a three-class motor imagery (MI) screening (left hand, right hand, feet) was performed with a group of 10 able-bodied and 16 complete spinal-cord-injured people (paraplegics, tetraplegics) with the objective of determining what differences were present between the user groups and how they would impact upon the ability of these user groups to interact with a BCI. Approach. Electrophysiological differences between patient groups and healthy users are measured in terms of sensorimotor rhythm deflections from baseline during MI, electroencephalogram microstate scalp maps and strengths of inter-channel phase synchronization. Additionally, using a common spatial pattern algorithm and a linear discriminant analysis classifier, the classification accuracy was calculated and compared between groups. Main results. It is seen that both patient groups (tetraplegic and paraplegic) have some significant differences in event-related desynchronization strengths, exhibit significant increases in synchronization and reach significantly lower accuracies (mean (M) = 66.1%) than the group of healthy subjects (M = 85.1%). Significance. The results demonstrate significant differences in electrophysiological correlates of motor control between healthy individuals and those individuals who stand to benefit most from BCI technology (individuals with SCI). They highlight the difficulty in directly translating results from healthy subjects to participants with SCI and the challenges that, therefore, arise in providing BCIs to such individuals.

  6. Assembling A Multi-Feature EEG Classifier for Left-Right Motor Imagery Data Using Wavelet-Based Fuzzy Approximate Entropy for Improved Accuracy.

    Hsu, Wei-Yen

    2015-12-01

    An EEG classifier is proposed for application in the analysis of motor imagery (MI) EEG data from a brain-computer interface (BCI) competition in this study. Applying subject-action-related brainwave data acquired from the sensorimotor cortices, the system primarily consists of artifact and background removal, feature extraction, feature selection and classification. In addition to background noise, the electrooculographic (EOG) artifacts are also automatically removed to further improve the analysis of EEG signals. Several potential features, including amplitude modulation, spectral power and asymmetry ratio, adaptive autoregressive model, and wavelet fuzzy approximate entropy (wfApEn) that can measure and quantify the complexity or irregularity of EEG signals, are then extracted for subsequent classification. Finally, the significant sub-features are selected from feature combination by quantum-behaved particle swarm optimization and then classified by support vector machine (SVM). Compared with feature extraction without wfApEn on MI data from two data sets for nine subjects, the results indicate that the proposed system including wfApEn obtains better performance in average classification accuracy of 88.2% and average number of commands per minute of 12.1, which is promising in the BCI work applications. PMID:26584583

  7. Single Trial Predictors for Gating Motor-Imagery Brain-Computer Interfaces Based on Sensorimotor Rhythm and Visual Evoked Potentials

    Geronimo, Andrew; Kamrunnahar, Mst; Schiff, Steven J.

    2016-01-01

    For brain-computer interfaces (BCIs) that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of ongoing processes, visual evoked responses, and voluntary modulation. We proposed to use three brain signatures for predicting success on a single trial of a BCI task. The first two features, the amplitude and phase of the pre-trial mu amplitude, were chosen as a correlate for cortical excitability. The remaining feature, related to the visually evoked response to the cue, served as a possible measure of fixation and attention to the task. Of these three features, mu rhythm amplitude over the central electrodes at the time of cue presentation and to a lesser extent the single trial visual evoked response were correlated with the success on the subsequent imagery task. Despite the potential for gating trials using these features, an offline gating simulation was limited in its ability to produce an increase in device throughput. This discrepancy highlights a distinction between the identification of predictive features, and the use of this knowledge in an online BCI. Using such a system, we cannot assume that the user will respond similarly when faced with a scenario where feedback is altered by trials that are gated on a regular basis. The results of this study suggest the possibility of using individualized, pre-task neural signatures for personalized, and asynchronous (self-paced) BCI applications, although these effects need to be quantified in a real-time adaptive scenario in a future study. PMID:27199630

  8. Kinesthetic imagery of musical performance.

    Lotze, Martin

    2013-01-01

    Musicians use different kinds of imagery. This review focuses on kinesthetic imagery, which has been shown to be an effective complement to actively playing an instrument. However, experience in actual movement performance seems to be a requirement for a recruitment of those brain areas representing movement ideation during imagery. An internal model of movement performance might be more differentiated when training has been more intense or simply performed more often. Therefore, with respect to kinesthetic imagery, these strategies are predominantly found in professional musicians. There are a few possible reasons as to why kinesthetic imagery is used in addition to active training; one example is the need for mental rehearsal of the technically most difficult passages. Another reason for mental practice is that mental rehearsal of the piece helps to improve performance if the instrument is not available for actual training as is the case for professional musicians when they are traveling to various appearances. Overall, mental imagery in musicians is not necessarily specific to motor, somatosensory, auditory, or visual aspects of imagery, but integrates them all. In particular, the audiomotor loop is highly important, since auditory aspects are crucial for guiding motor performance. All these aspects result in a distinctive representation map for the mental imagery of musical performance. This review summarizes behavioral data, and findings from functional brain imaging studies of mental imagery of musical performance. PMID:23781196

  9. Large-Scale Assessment of a Fully Automatic Co-Adaptive Motor Imagery-Based Brain Computer Interface

    Acqualagna, Laura; Botrel, Loic; Vidaurre, Carmen; Kübler, Andrea; Blankertz, Benjamin

    2016-01-01

    In the last years Brain Computer Interface (BCI) technology has benefited from the development of sophisticated machine leaning methods that let the user operate the BCI after a few trials of calibration. One remarkable example is the recent development of co-adaptive techniques that proved to extend the use of BCIs also to people not able to achieve successful control with the standard BCI procedure. Especially for BCIs based on the modulation of the Sensorimotor Rhythm (SMR) these improvements are essential, since a not negligible percentage of users is unable to operate SMR-BCIs efficiently. In this study we evaluated for the first time a fully automatic co-adaptive BCI system on a large scale. A pool of 168 participants naive to BCIs operated the co-adaptive SMR-BCI in one single session. Different psychological interventions were performed prior the BCI session in order to investigate how motor coordination training and relaxation could influence BCI performance. A neurophysiological indicator based on the Power Spectral Density (PSD) was extracted by the recording of few minutes of resting state brain activity and tested as predictor of BCI performances. Results show that high accuracies in operating the BCI could be reached by the majority of the participants before the end of the session. BCI performances could be significantly predicted by the neurophysiological indicator, consolidating the validity of the model previously developed. Anyway, we still found about 22% of users with performance significantly lower than the threshold of efficient BCI control at the end of the session. Being the inter-subject variability still the major problem of BCI technology, we pointed out crucial issues for those who did not achieve sufficient control. Finally, we propose valid developments to move a step forward to the applicability of the promising co-adaptive methods. PMID:26891350

  10. User Experience May be Producing Greater Heart Rate Variability than Motor Imagery Related Control Tasks during the User-System Adaptation in Brain-Computer Interfaces

    Alonso-Valerdi, Luz M.; Gutiérrez-Begovich, David A.; Argüello-García, Janet; Sepulveda, Francisco; Ramírez-Mendoza, Ricardo A.

    2016-01-01

    Brain-computer interface (BCI) is technology that is developing fast, but it remains inaccurate, unreliable and slow due to the difficulty to obtain precise information from the brain. Consequently, the involvement of other biosignals to decode the user control tasks has risen in importance. A traditional way to operate a BCI system is via motor imagery (MI) tasks. As imaginary movements activate similar cortical structures and vegetative mechanisms as a voluntary movement does, heart rate variability (HRV) has been proposed as a parameter to improve the detection of MI related control tasks. However, HR is very susceptible to body needs and environmental demands, and as BCI systems require high levels of attention, perceptual processing and mental workload, it is important to assess the practical effectiveness of HRV. The present study aimed to determine if brain and heart electrical signals (HRV) are modulated by MI activity used to control a BCI system, or if HRV is modulated by the user perceptions and responses that result from the operation of a BCI system (i.e., user experience). For this purpose, a database of 11 participants who were exposed to eight different situations was used. The sensory-cognitive load (intake and rejection tasks) was controlled in those situations. Two electrophysiological signals were utilized: electroencephalography and electrocardiography. From those biosignals, event-related (de-)synchronization maps and event-related HR changes were respectively estimated. The maps and the HR changes were cross-correlated in order to verify if both biosignals were modulated due to MI activity. The results suggest that HR varies according to the experience undergone by the user in a BCI working environment, and not because of the MI activity used to operate the system. PMID:27458384

  11. Imaginería motora graduada en el síndrome de miembro fantasma con dolor Graded motor imagery in the phantom limb syndrome with pain

    M. A. Morales-Osorio

    2012-08-01

    Full Text Available Nuevas investigaciones sobre los cambios corticales en pacientes con dolor crónico han llevado a una reevaluación de las patologías que cursan con dolor crónico y sus tratamientos. Este es el caso del síndrome de miembro fantasma con dolor (SMFD, el cual se centraba en los estímulos nociceptivos periféricos, y ahora se replantean como una disfunción a nivel central. Una de las herramientas altamente evidencia y muchas veces desconocida para los terapeutas es la imaginería motora graduada (IMG. Esta técnica intenta normalizar la secuencia de procesamientos centrales para remediar el dolor crónico amparado en la neurociencias y en dos regalos de esta, como son las neuronas espejos y la neuromatriz. Este artículo resume brevemente los componentes básicos de la IMG, su aplicación y sus beneficios, la cual es la base de trabajo de nuestra línea de investigación, diseñado para los pacientes con SMFD, perteneciente a un centro clínico de la ciudad de Cartagena de Indias en Colombia.New investigations on cortical changes in patients with chronic pain have led to a reassessment of the pathologies that occur with chronic pain and its treatment. This is the case of Phantom limb syndrome with pain (PLP, which focused on peripheral nociceptive stimulus, and are now rethinking as a dysfunction at central level. One of the tools often highly evidence and therapists is unknown to the Graded motor imagery (IMG. This technique attempts to normalize the central processing sequence to remedy chronic pain, supported in the neurosciences and the two gifts, such as mirror neurons and the neuromatrix. This article briefly summarizes the basic components of IMG, your application and its benefits, which is the working basis of our research, designed for patients with SMFD belonging to a clinical center in Cartagena de Indias in Colombia.

  12. Kinesthetic imagery of musical performance

    Martin eLotze

    2013-06-01

    Full Text Available Musicians use different kinds of imagery. This review focuses on kinesthetic imagery, which has been shown to be an effective complement to actively playing an instrument. However, experience in actual movement performance seems to be a requirement for a recruitment of those brain areas representing movement ideation during imagery. An internal model of movement performance might be more differentiated when training has been more intense or simply performed more often. Therefore, with respect to kinesthetic imagery, these strategies are predominantly found in professional musicians. There are a few possible reasons as to why kinesthetic imagery is used in addition to active training; one example is the need for mental rehearsal of the technically most difficult passages. Training difficult passages repeatedly has the potential to induce fatigue in tendons and muscles and can ultimately result in the development of dystonia. Another reason for mental practice is that mental rehearsal of the piece helps to improve performance if the instrument is not available for actual training as is the case for professional musicians when they are travelling to various appearances. Overall, mental imagery in musicians is not necessarily specific to motor, somatosensory, auditory or visual aspects of imagery, but integrates them all. In particular, the audiomotor loop is highly important, since auditory aspects are crucial for guiding motor performance. Furthermore, slight co-movement, for instance of the fingers, usually occurs when imagining musical performance, a situation different to the laboratory condition where movement execution is strictly controlled. All these aspects result in a distinctive representation map for the mental imagery of musical performance. This review summarizes behavioral data, and findings from functional brain imaging studies of mental imagery of musical performance.

  13. Selective deficit of praxis imagery in ideomotor apraxia.

    Ochipa, C; Rapcsak, S Z; Maher, L M; Rothi, L J; Bowers, D; Heilman, K M

    1997-08-01

    We studied imagery for learned, skilled movements (praxis imagery) in a patient with severe ideomotor apraxia and intact language abilities. This patient, who made predominantly spatial and movement errors when performing transitive movements demonstrating the use of tools (transitive gestures), was also impaired in her ability to answer imagery questions about joint movement or the spatial position of the hands during action. However, visual object imagery was spared. The finding of parallel praxis production and praxis imagery deficits in this patient suggests that the same representations used for gesture production are also activated during imagery of motor acts. Our findings also suggest that certain aspects of motor imagery may be dissociable from general object imagery. PMID:9270580

  14. Rationales for improving motor function.

    Hummelsheim, H

    1999-12-01

    New findings in basic neuroscience, and the growing knowledge regarding neuroplasticity and motor learning have exerted influence and have provided stimuli for motor rehabilitation research. Repeated motor practice has been identified as crucial for motor recovery. Further novel and scientifically based therapeutic approaches have been developed: constraint-induced movement therapy, electromyogram-initiated neuromuscular stimulation, motor imagery and music therapy are all discussed in the present review. PMID:10676751

  15. Effects of kinesthetic versus visual imagery practice on two technical dance movements: a pilot study.

    Girón, Elizabeth Coker; McIsaac, Tara; Nilsen, Dawn

    2012-03-01

    Motor imagery is a type of mental practice that involves imagining the body performing a movement in the absence of motor output. Dance training traditionally incorporates mental practice techniques, but quantitative effects of motor imagery on the performance of dance movements are largely unknown. This pilot study compared the effects of two different imagery modalities, external visual imagery and kinesthetic imagery, on pelvis and hip kinematics during two technical dance movements, plié and sauté. Each of three female dance students (mean age = 19.7 years, mean years of training = 10.7) was assigned to use a type of imagery practice: visual imagery, kinesthetic imagery, or no imagery. Effects of motor imagery on peak external hip rotation varied by both modality and task. Kinesthetic imagery increased peak external hip rotation for pliés, while visual imagery increased peak external hip rotation for sautés. Findings suggest that the success of motor imagery in improving performance may be task-specific. Dancers may benefit from matching imagery modality to technical tasks in order to improve alignment and thereby avoid chronic injury. PMID:22390952

  16. EEG changes during sequences of visual and kinesthetic motor imagery Alterações no EEG durante sequencias de imagética motora visual e cinestésica

    Marcus Vinicius Stecklow

    2010-08-01

    Full Text Available The evoked cerebral electric response when sequences of complex motor imagery (MI task are executed several times is still unclear. This work aims at investigating the existence of habituation in the cortical response, more specifically in the alpha band peak of parietal and occipital areas (10-20 international system electroencephalogram, EEG, protocol. The EEG signals were acquired during sequences of MI of volleyball spike movement in kinesthetic and visual modalities and also at control condition. Thirty right-handed male subjects (18 to 40 years were assigned to either an 'athlete' or a 'non-athlete' group, both containing 15 volunteers. Paired Wilcoxon tests (with α=0.05 indicates that sequential MI of complex tasks promotes cortical changes, mainly in the power vicinity of the alpha peak. This finding is more pronounced along the initial trials and also for the athletes during the modality of kinesthetic motor imagery.A resposta elétrica cerebral evocada quando sequencias de imagética motora (MI de tarefas complexas são executadas seguidamente no tempo permanecem desconhecidas. Este trabalho objetivou investigar a existência de habituação da resposta cortical, mais especificamente na banda do pico de alfa de áreas parietais e occipitais (sistema internacional 10-20, eletroencefalograma, protocolo de EEG. Os sinais de EEG foram adquiridos durante sequências de MI do movimento de ataque do voleibol nas modalidades cinestésica e visual, e também em condição de controle. Trinta voluntários adultos (entre 18 e 40 anos, destros, do gênero masculino foram agrupados como 'atletas' ou 'não-atletas', sendo cada grupo composto de 15 voluntários. Testes pareados de Wilcoxon (com α=0.05 indicaram que a MI sequencial de tarefas complexas promoveram alterações nas respostas corticais, mais especificamente na região ao redor do pico de alfa. Este achado foi mais pronunciado ao longo dos trechos iniciais e também nos atletas durante

  17. Motor cortical plasticity induced by motor learning through mental practice.

    Nicolas Gueugneau

    2015-04-01

    Full Text Available Several investigations suggest that actual and mental actions trigger similar neural substrates. Motor learning via physical practice results in long-term potentiation (LTP-like plasticity processes, namely potentiation of M1 and a temporary occlusion of additional LTP-like plasticity. However, whether this neuroplasticity process contributes to improve motor performance through mental practice remains to be determined. Here, we tested skill learning-dependent changes in primary motor cortex (M1 excitability and plasticity by means of transcranial magnetic stimulation in subjects trained to physically execute or mentally perform a sequence of finger opposition movements. Before and after physical practice and motor-imagery practice, M1 excitability was evaluated by measuring the input-output (IO curve of motor evoked potentials. M1 long-term potentiation (LTP and long-term depression (LTD-like plasticity was assessed with paired-associative stimulation (PAS of the median nerve and motor cortex using an interstimulus interval of 25 ms (PAS25 or 10 ms (PAS10, respectively. We found that even if after both practice sessions subjects significantly improved their movement speed, M1 excitability and plasticity were differentially influenced by the two practice sessions. First, we observed an increase in the slope of IO curve after physical but not after motor-imagery practice. Second, there was a reversal of the PAS25 effect from LTP-like plasticity to LTD-like plasticity following physical and motor-imagery practice. Third, LTD-like plasticity (PAS10 protocol increased after physical practice, whilst it was occluded after motor-imagery practice. In conclusion, we demonstrated that motor-imagery practice lead to the development of neuroplasticity, as it affected the PAS25- and PAS10- induced plasticity in M1. These results, expanding the current knowledge on how motor-imagery training shapes M1 plasticity, might have a potential impact in

  18. 运动想象疗法对急性脑梗死患者上肢瘫痪的效果及脑功能MRI的改变%Effects and changes of brain functional MRI of motor imagery therapy on acute cerebral infarction patients with upper limb paralysis

    冉茂胜; 叶建军; 马东兵; 张莉; 胡杰杰; 杨旭君; 乔小民; 姜晓萍

    2013-01-01

    Objective To investigate the effects and changes of brain functional MRI (fMRI) of motor imagery therapy on acute cerebral infarction ( ACI) patients with upper limb paralysis. Methods Seventy cases of ACI patients with hemiplegia were randomly divided into the control group (drug therapy + exercise) and motor imagery therapy group, each group had 35 cases. The treatment of motor imagery therapy group was on the basis of control group, add into motor imagery therapy, 2 times a day, for 30 d. Before and 30 d after treatment, the patients were scored by Fugl-Meyer scale (FMA) and functional independence measure scale (FIM) , the active range of motion ( AROM) of ipsilateral wrist was measured by a protractor, and the brain movement activation range was measured by blood oxygen level dependent fMRI. Results After treatment, the FMA, FIM scores of paralysis upper extremity, the AROM and range of brain activation were significantly higher or bigger than before treatment in the two groups (P<0. 05 -0.01). And these indicators of motor imagery therapy group were significantly higher or bigger than those in the control group (P<0. 05 —0.01). Conclusions Motor imagery therapy can promote the recovery of the upper limb motor function in acute cerebral infarction patients with hemiplegia, and expand the brain movement activation range on fMRI.%目的 研究运动想象疗法对急性脑梗死患者上肢瘫痪的效果及脑功能MRI(fMRI)的改变.方法 70例脑梗死偏瘫患者,随机分为对照组(药物治疗+运动)和运动想象治疗组,每组35例.运动想象治疗组在对照组的治疗基础上,进行运动想象疗法,每天2次,连续30 d.在治疗前和治疗后30 d,给患者进行Fugl-Meyer量表(FMA)、功能独立性评定量表(FIM)评分,用量角器测定患侧手腕主动活动范围(AROM);用血氧水平依赖性fMRI测定脑运动激活区范围.结果 两组患者治疗后瘫痪上肢的FMA、FIM评分、AROM及脑激活区的范围均明

  19. Suomi NPP VIIRS Imagery evaluation

    Hillger, Donald; Seaman, Curtis; Liang, Calvin; Miller, Steven; Lindsey, Daniel; Kopp, Thomas

    2014-06-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) combines the best aspects of both civilian and military heritage instrumentation. VIIRS has improved capabilities over its predecessors: a wider swath width and much higher spatial resolution at swath edge. The VIIRS day-night band (DNB) is sensitive to very low levels of visible light and is capable of detecting low clouds, land surface features, and sea ice at night, in addition to light emissions from both man-made and natural sources. Imagery from the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite has been in the checkout process since its launch on 28 October 2011. The ongoing evaluation of VIIRS Imagery helped resolve several imagery-related issues, including missing radiance measurements. In particular, near-constant contrast imagery, derived from the DNB, had a large number of issues to overcome, including numerous missing or blank-fill images and a stray light leakage problem that was only recently resolved via software fixes. In spite of various sensor issues, the VIIRS DNB has added tremendous operational and research value to Suomi NPP. Remarkably, it has been discovered to be sensitive enough to identify clouds even in very low light new moon conditions, using reflected light from the Earth's airglow layer. Impressive examples of the multispectral imaging capabilities are shown to demonstrate its applications for a wide range of operational users. Future members of the Joint Polar Satellite System constellation will also carry and extend the use of VIIRS. Imagery evaluation will continue with these satellites to ensure the quality of imagery for end users.

  20. Postura da mão e imagética motora: um estudo sobre reconhecimento de partes do corpo Hand posture and motor imagery: a body-part recognition study

    AP Lameira

    2008-10-01

    Full Text Available OBJETIVOS: Assim como a imagética motora, o reconhecimento de partes do corpo aciona representações somatosensoriais específicas. Essas representações são ativadas implicitamente para comparar o corpo com o estímulo. No presente estudo, investigou-se a influência da informação proprioceptiva da postura no reconhecimento de partes do corpo (mãos e propõe-se a utilização dessa tarefa na reabilitação de pacientes neurológicos. MATERIAIS E MÉTODOS: Dez voluntários destros participaram do experimento. A tarefa era reconhecer a lateralidade de figuras da mão apresentada, em várias perspectivas e em vários ângulos de orientação. Para a figura da mão direita, o voluntário pressionava a tecla direita e para a figura da mão esquerda, a tecla esquerda. Os voluntários realizavam duas sessões: uma com as mãos na postura prona e outra com as mãos na postura supina. RESULTADOS: Os tempos de reação manual (TRM eram maiores para as vistas e orientações, nas quais é difícil realizar o movimento real, mostrando que durante a tarefa, existe um acionamento de representações motoras para comparar o corpo com o estímulo. Além disso, existe uma influência da postura do sujeito em vistas e ângulos específicos. CONCLUSÕES: Estes resultados mostram que representações motoras são ativadas para comparar o corpo com o estímulo e que a postura da mão influencia esta ressonância entre estímulo e parte do corpo.OBJECTIVE: Recognition of body parts activates specific somatosensory representations in a way that is similar to motor imagery. These representations are implicitly activated to compare the body with the stimulus. In the present study, we investigate the influence of proprioceptive information relating to body posture on the recognition of body parts (hands. It proposes that this task could be used for rehabilitation of neurological patients. METHODS: Ten right-handed volunteers participated in this experiment. The

  1. Phenomenology of intrusive imagery in obsessive compulsive disorder (OCD).

    Lipton, M.

    2008-01-01

    The study of intrusive mental imagery in anxiety is a growing area of interest. Whilst there is an appreciation of the variation in thematic content (Hirsch & Holmes, 2007), less is understood about the wider phenomenology and function of intrusive imagery across the anxiety disorders. The aim of the review is to adopt a transdiagnostic perspective, and compare and contrast the literature on intrusive imagery in anxiety in terms of the content, prevalence, frequency and characteristics. In ad...

  2. Application of digital signal processor in brain-computer interface based on motor imagery potential%DSP在基于想象动作电位的脑-机接口中的应用

    赵丽; 高新

    2012-01-01

    应用数字信号处理器设计了一个基于想象动作电位的脑-机接口系统,通过模拟滤波与数字信号器处理相结合的方法,实现了对想象动作电位信息的有效采集和处理.系统在硬件上设计了脑电信号放大器,DSP开发板;对脑电信号放大、AD转换后,通过分类特征提取处理后,完成动作识别与控制命令的输出.将数字信号处理器应用在脑-机接口中,利用数字信号处理器优异的处理能力和丰富的外设资源,实现了一个嵌入式、微型化的脑-机接口构建,实现了脑-机接口实时处理与微型化.%This paper presents motor-imaginary-potential-based brain-computer interface (BCI) interface by using digital signal processor (DSP). Combining analog filtering and digital processing; realize the motor imaginary potential information acquisition effectively and processing. A EEG amplifier and DSP development board were designed in system for hardware. Motor imaginary potential information through EEG-amplifier and AD converted, after classification and feature extraction,gesture recognition will be completed and control command will be output to control peripherals. In this paper, digital signal processor (DSP) is used in brain-computer interface (BCI), using the DSP achieved a brain-computer interface real-time processing and miniaturization with its excellent processing power and rich resources of the peripheral. A on embedded technology Based, Miniaturization of brain-computer interface was built.

  3. NAIP 2015 Imagery Feedback

    Farm Service Agency, Department of Agriculture — The NAIP 2015 Imagery Feedback web application allows users to make comments and observations about the quality of the 2015 National Agriculture Imagery Program...

  4. Current Resource Imagery Projects

    Farm Service Agency, Department of Agriculture — Map showing coverage of current Resource imagery projects. High resolution/large scale Resource imagery is typically acquired for the U.S. Forest Service and other...

  5. NAIP 2014 Imagery Feedback

    Farm Service Agency, Department of Agriculture — The NAIP 2014 Imagery Feedback map allows users to make comments and observations about the quality of the 2014 National Agriculture Imagery Program (NAIP)...

  6. Mental Representation and Motor Imagery Training

    Thomas eSchack; Kai eEssig; Cornelia eFrank; Dirk eKoester

    2014-01-01

    Research in sports, dance and rehabilitation has shown that Basic Action Concepts (BACs) are fundamental building blocks of mental action representations. BACs are based on chunked body postures related to common functions for realizing action goals. In this paper, we outline issues in research methodology and an experimental method, SDA-M (structural dimensional analysis of mental representation), to assess action-relevant representational structures that reflect the organization of BACs. Th...

  7. Mental representation and motor imagery training

    Schack, Thomas; Essig, Kai; Frank, Cornelia; Koester, Dirk

    2014-01-01

    Research in sports, dance and rehabilitation has shown that basic action concepts (BACs) are fundamental building blocks of mental action representations. BACs are based on chunked body postures related to common functions for realizing action goals. In this paper, we outline issues in research methodology and an experimental method, the structural dimensional analysis of mental representation (SDA-M), to assess action-relevant representational structures that reflect the organization of BACs...

  8. Aerial Photography and Imagery, Ortho-Corrected - VOLUSIA 2006 Orthophotography

    NSGIC GIS Inventory (aka Ramona) — 2006, 6 inch Pixel Color Orthophotography - - Panchromatic, red, green, blue and near infrared imagery was acquired using the Leica ADS40 multi-spectral scanner...

  9. Planning, preparation, execution, and imagery of volitional action.

    Deecke, L

    1996-03-01

    There are different motor sets, which a human subject can be in or act from: he or she can be in a self-initiated voluntary movement set (action) or in a response set (re-action). Also, imagery sets are available that are necessary for the acquisition and practice of skill. Most important are such imagery sets for rehearsal in theatre, dance, music, sports, combat, etc. PMID:8713545

  10. Planning, preparation, execution, and imagery of volitional action

    Deecke, Lüder

    1996-01-01

    There are different motor sets, which a human subject can be in or act from: He or she can be in a self-initiated voluntary movement set (action) or in a response set (re-action). Also, imagery sets are available that are necessary for the acquisition and practice of skill. Most important are such imagery sets for rehearsal in theatre, dance, music, sports, combat, etc.

  11. Hairy AdS Solitons

    Anabalon, Andres; Choque, David

    2016-01-01

    We construct exact hairy AdS soliton solutions in Einstein-dilaton gravity theory. We discuss the role of these solutions for the existence of first order phase transitions for planar hairy black holes within these theories.

  12. Auditory-motor learning influences auditory memory for music.

    Brown, Rachel M; Palmer, Caroline

    2012-05-01

    In two experiments, we investigated how auditory-motor learning influences performers' memory for music. Skilled pianists learned novel melodies in four conditions: auditory only (listening), motor only (performing without sound), strongly coupled auditory-motor (normal performance), and weakly coupled auditory-motor (performing along with auditory recordings). Pianists' recognition of the learned melodies was better following auditory-only or auditory-motor (weakly coupled and strongly coupled) learning than following motor-only learning, and better following strongly coupled auditory-motor learning than following auditory-only learning. Auditory and motor imagery abilities modulated the learning effects: Pianists with high auditory imagery scores had better recognition following motor-only learning, suggesting that auditory imagery compensated for missing auditory feedback at the learning stage. Experiment 2 replicated the findings of Experiment 1 with melodies that contained greater variation in acoustic features. Melodies that were slower and less variable in tempo and intensity were remembered better following weakly coupled auditory-motor learning. These findings suggest that motor learning can aid performers' auditory recognition of music beyond auditory learning alone, and that motor learning is influenced by individual abilities in mental imagery and by variation in acoustic features. PMID:22271265

  13. Performance improvements from imagery:evidence that internal visual imagery is superior to external visual imagery for slalom performance

    Nichola eCallow

    2013-10-01

    Full Text Available We report three experiments investigating the hypothesis that use of internal visual imagery (IVI would be superior to external visual imagery (EVI for the performance of different slalom-based motor tasks. In Experiment 1, three groups of participants (IVI, EVI, and a control group performed a driving-simulation slalom task. The IVI group achieved significantly quicker lap times than EVI and the control group. In Experiment 2, participants performed a downhill running slalom task under both IVI and EVI conditions. Performance was again quickest in the IVI compared to EVI condition, with no differences in accuracy. Experiment 3 used the same group design as Experiment 1, but with participants performing a downhill ski-slalom task. Results revealed the IVI group to be significantly more accurate than the control group, with no significant differences in time taken to complete the task. These results support the beneficial effects of IVI for slalom-based tasks, and significantly advances our knowledge related to the differential effects of visual imagery perspectives on motor performance.

  14. Imagery Integration Team

    Calhoun, Tracy; Melendrez, Dave

    2014-01-01

    The Human Exploration Science Office (KX) provides leadership for NASA's Imagery Integration (Integration 2) Team, an affiliation of experts in the use of engineering-class imagery intended to monitor the performance of launch vehicles and crewed spacecraft in flight. Typical engineering imagery assessments include studying and characterizing the liftoff and ascent debris environments; launch vehicle and propulsion element performance; in-flight activities; and entry, landing, and recovery operations. Integration 2 support has been provided not only for U.S. Government spaceflight (e.g., Space Shuttle, Ares I-X) but also for commercial launch providers, such as Space Exploration Technologies Corporation (SpaceX) and Orbital Sciences Corporation, servicing the International Space Station. The NASA Integration 2 Team is composed of imagery integration specialists from JSC, the Marshall Space Flight Center (MSFC), and the Kennedy Space Center (KSC), who have access to a vast pool of experience and capabilities related to program integration, deployment and management of imagery assets, imagery data management, and photogrammetric analysis. The Integration 2 team is currently providing integration services to commercial demonstration flights, Exploration Flight Test-1 (EFT-1), and the Space Launch System (SLS)-based Exploration Missions (EM)-1 and EM-2. EM-2 will be the first attempt to fly a piloted mission with the Orion spacecraft. The Integration 2 Team provides the customer (both commercial and Government) with access to a wide array of imagery options - ground-based, airborne, seaborne, or vehicle-based - that are available through the Government and commercial vendors. The team guides the customer in assembling the appropriate complement of imagery acquisition assets at the customer's facilities, minimizing costs associated with market research and the risk of purchasing inadequate assets. The NASA Integration 2 capability simplifies the process of securing one

  15. Auditory imagery: empirical findings.

    Hubbard, Timothy L

    2010-03-01

    The empirical literature on auditory imagery is reviewed. Data on (a) imagery for auditory features (pitch, timbre, loudness), (b) imagery for complex nonverbal auditory stimuli (musical contour, melody, harmony, tempo, notational audiation, environmental sounds), (c) imagery for verbal stimuli (speech, text, in dreams, interior monologue), (d) auditory imagery's relationship to perception and memory (detection, encoding, recall, mnemonic properties, phonological loop), and (e) individual differences in auditory imagery (in vividness, musical ability and experience, synesthesia, musical hallucinosis, schizophrenia, amusia) are considered. It is concluded that auditory imagery (a) preserves many structural and temporal properties of auditory stimuli, (b) can facilitate auditory discrimination but interfere with auditory detection, (c) involves many of the same brain areas as auditory perception, (d) is often but not necessarily influenced by subvocalization, (e) involves semantically interpreted information and expectancies, (f) involves depictive components and descriptive components, (g) can function as a mnemonic but is distinct from rehearsal, and (h) is related to musical ability and experience (although the mechanisms of that relationship are not clear). PMID:20192565

  16. Imagery and Improvisation in Dance in the Schools.

    Magruder, Ella

    1981-01-01

    Improvisation and imagery should be used to strengthen the thin bond between creativity and motor development in children. The approach to dance as an improvisational tool should be made more concrete when working with special populations such as mentally handicapped students. (JN)

  17. KINESTHETIC IMAGERY TRAINING OF FORCEFUL MUSCLE CONTRACTIONS INCREASES BRAIN SIGNAL AND MUSCLE STRENGTH

    Wan X Yao

    2013-09-01

    Full Text Available The purpose of this study was to compare the effect of training using internal imagery (IMI; also known as kinesthetic imagery or first person imagery with that of external imagery (EMI; also known as third-person visual imagery of strong muscle contractions on voluntary muscle strengthening. Eighteen young, healthy subjects were randomly assigned to one of three groups (6 in each group: internal motor imagery (IMI, external motor imagery (EMI, or a no-practice control (CTRL group. Training lasted for 6 weeks (~15 min/day, 5 days/week. The participants’ right arm elbow-flexion strength, muscle electrical activity and movement-related cortical potential (MRCP were evaluated before and after training. Only the IMI group showed significant strength gained (10.8% while the EMI (4.8% and CTRL (-3.3% groups did not. Only the IMI group showed a significant elevation in MRCP on scalp locations over both the primary motor (M1 and supplementary motor cortices (EMI group over M1 only and this increase was significantly greater than that of EMI and CTRL groups. These results suggest that training by IMI of forceful muscle contractions was effective in improving voluntary muscle strength without physical exercise. We suggest that the IMI training likely strengthened brain-to-muscle (BTM command that may have improved motor unit recruitment and activation, and led to greater muscle output. Training by internal motor imagery of forceful muscle contractions may change the activity level of cortical motor control network, which may translate into greater descending command to the target muscle and increase its strength.

  18. Coastal California Digital Imagery

    National Oceanic and Atmospheric Administration, Department of Commerce — This digital ortho-imagery dataset is a survey of coastal California. The project area consists of approximately 3774 square miles. The project design of the...

  19. SHEBA Reconnaissance Imagery

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of optical band reconnaissance imagery of the Surface Heat Balance of the Arctic (SHEBA) site acquired between August 1997 and September...

  20. NOAA Emergency Response Imagery

    National Oceanic and Atmospheric Administration, Department of Commerce — The imagery posted on this site is in response to natural disasters. The aerial photography missions were conducted by the NOAA Remote Sensing Division. The...

  1. Added Sugars

    ... Restaurant Deciphering the Menu Ordering Your Meal Eating Fast Food Dining Out Tips by Cuisine Physical Activity Fitness ... Learn more about reading food labels . Limit your consumption of foods with high amounts of added sugars, ...

  2. Commercial imagery archive product development

    Sakkas, Alysa

    1999-12-01

    The Lockheed Martin (LM) team had garnered over a decade of operational experience in digital imagery management and analysis for the US Government at numerous worldwide sites. Recently, it set out to create a new commercial product to serve the needs of large-scale imagery archiving and analysis markets worldwide. LM decided to provide a turnkey commercial solution to receive, store, retrieve, process, analyze and disseminate in 'push' or 'pull' modes components and adapted and developed its own algorithms to provide added functionality not commercially available elsewhere. The resultant product, Intelligent Library System, satisfies requirements for (a) a potentially unbounded, data archive automated workflow management for increased user productivity; (c) automatic tracking and management of files stored on shelves; (d) ability to ingest, process and disseminate data involves with bandwidths ranging up to multi-gigabit per second; (e) access through a thin client- to-server network environment; (f) multiple interactive users needing retrieval of filters in seconds from both archived images or in real time, and (g) scalability that maintains information throughput performance as the size of the digital library grows.

  3. Wormholes in AdS

    Maldacena, Juan; Maoz, Liat

    2004-01-01

    We construct a few Euclidean supergravity solutions with multiple boundaries. We consider examples where the corresponding boundary field theory is well defined on each boundary. We point out that these configurations are puzzling from the AdS/CFT point of view. A proper understanding of the AdS/CFT dictionary for these cases might yield some information about the physics of closed universes.

  4. Mental imagery for musical changes in loudness

    Freya eBailes

    2012-12-01

    Full Text Available Musicians imagine music during mental rehearsal, when reading from a score, and while composing. An important characteristic of music is its temporality. Among the parameters that vary through time is sound intensity, perceived as patterns of loudness. Studies of mental imagery for melodies (i.e. pitch and rhythm show interference from concurrent musical pitch and verbal tasks, but how we represent musical changes in loudness is unclear. Theories suggest that our perceptions of loudness change relate to our perceptions of force or effort, implying a motor representation. An experiment was conducted to investigate the modalities that contribute to imagery for loudness change. Musicians performed a within-subjects loudness change recall task, comprising 48 trials. First, participants heard a musical scale played with varying patterns of loudness, which they were asked to remember. There followed an empty interval of 8 seconds (nil distractor control, or the presentation of a series of 4 sine tones, or 4 visual letters or 3 conductor gestures, also to be remembered. Participants then saw an unfolding score of the notes of the scale, during which they were to imagine the corresponding scale in their mind while adjusting a slider to indicate the imagined changes in loudness. Finally, participants performed a recognition task of the tone, letter or gesture sequence. Based on the motor hypothesis, we predicted that observing and remembering conductor gestures would impair loudness change scale recall, while observing and remembering tone or letter string stimuli would not. Results support this prediction, with loudness change recalled less accurately in the gestures condition than in the control condition. An effect of musical training suggests that auditory and motor imagery ability may be closely related to domain expertise.

  5. Adding Ajax

    Powers, Shelley

    2007-01-01

    Ajax can bring many advantages to an existing web application without forcing you to redo the whole thing. This book explains how you can add Ajax to enhance, rather than replace, the way your application works. For instance, if you have a traditional web application based on submitting a form to update a table, you can enhance it by adding the capability to update the table with changes to the form fields, without actually having to submit the form. That's just one example.Adding Ajax is for those of you more interested in extending existing applications than in creating Rich Internet Applica

  6. Efeito das terapias associadas de imagem motora e de movimento induzido por restrição na hemiparesia crônica: estudo de caso Effects of associated therapies of motor imagery and constraint-induced movement in chronic hemiparesis: a case study

    Claudia Morais Trevisan

    2010-09-01

    Full Text Available Este estudo analisa os efeitos da associação das terapias de imagem motora e de movimento induzido por restrição na reeducação funcional do membro superior (MS de um paciente com deficit sensorial e motor determinado por acidente vascular encefálico (AVE. A terapia de imagem motora (IM consistiu em: 1o, estimulo visual do espelho, em 3 sessões semanais de 30 a 60 minutos por 4 semanas; e 2o, IM com prática mental, em 3 sessões semanais de 15 minutos por 3 semanas. Por último foi aplicada a terapia de indução ao movimento por restrição do membro superior não-afetado por 14 dias, em 10 dos quais foi feita atividade funcional do membro parético por 6 horas diárias. Além da avaliação clinica da sensibilidade e medida da força de preensão palmar, antes do tratamento e após cada modalidade de terapia foi medida a amplitude de movimentos de ombro, cotovelo e punho e aplicada a escala de avaliação motora (EAM. Os escores dos quatro momentos da coleta foram comparados estatisticamente. Após o tratamento os resultados mostraram diferença significativa (pThis study assessed the efficacy of the association of motor imagery and constraint-induced movement therapies in functional rehabilitation of the upper limb in a patient with somatosensory and motor deficits following stroke. Motor imagery (MI therapy, i.e., mental simulation of body image, consisted in: 1st, mirror visual stimulus, at three 30-60-minute weekly sessions for four weeks; and 2nd, MI with mental practice, at three 15-minute sessions per week for three weeks. Lastly, constraint-induced movement therapy was applied for 14 days, in 10 of which the patient underwent 6 hours daily of paretic limb functional training. The patient was assessed at baseline and at the end of each therapy modality as to clinical examination of sensation; hand grip strength; shoulder, elbow and wrist range of motion; and the motor assessment scale (MAS was applied. Scores obtained at the

  7. NAIP 2015 Imagery Feedback Map

    Farm Service Agency, Department of Agriculture — The NAIP 2015 Imagery Feedback map allows users to make comments and observations about the quality of the 2015 National Agriculture Imagery Program (NAIP)...

  8. Infrared Imagery of Solid Rocket Exhaust Plumes

    Moran, Robert P.; Houston, Janice D.

    2011-01-01

    The Ares I Scale Model Acoustic Test program consisted of a series of 18 solid rocket motor static firings, simulating the liftoff conditions of the Ares I five-segment Reusable Solid Rocket Motor Vehicle. Primary test objectives included acquiring acoustic and pressure data which will be used to validate analytical models for the prediction of Ares 1 liftoff acoustics and ignition overpressure environments. The test article consisted of a 5% scale Ares I vehicle and launch tower mounted on the Mobile Launch Pad. The testing also incorporated several Water Sound Suppression Systems. Infrared imagery was employed during the solid rocket testing to support the validation or improvement of analytical models, and identify corollaries between rocket plume size or shape and the accompanying measured level of noise suppression obtained by water sound suppression systems.

  9. Teaching about operation of brushless DC motors

    Čufar, Aleksandra

    2013-01-01

    Brush DC motor is being replaced by brushless DC motors on every area of application. My diploma thesis is a presentation of brushless DC motor, how it works and its application. Within first part we describe various electric motors and their application. There are several types of electric motors division. Last to be added is a brushless motor. Within second part of thesis we look into a brushless DC motor, how it works, its application and control. In the third part of thesis we construct a...

  10. Solar Imagery - Chromosphere - Calcium

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about...

  11. Selective Efficacy of Static and Dynamic Imagery in Different States of Physical Fatigue.

    Thiago Ferreira Dias Kanthack

    Full Text Available There is compelling evidence that motor imagery contributes to improved motor performance, and recent work showed that dynamic motor imagery (dMI might provide additional benefits by comparison with traditional MI practice. However, the efficacy of motor imagery in different states of physical fatigue remains largely unknown, especially as imagery accuracy may be hampered by the physical fatigue states elicited by training. We investigated the effect of static motor imagery (sMI and dMI on free-throw accuracy in 10 high-level basketball athletes, both in a non-fatigued state (Experiment 1 and immediately after an incremental running test completed until exhaustion (20 m shuttle run-test-Experiment 2. We collected perceived exhaustion and heart rate to quantify the subjective experience of fatigue and energy expenditure. We found that dMI brought better shooting performance than sMI, except when athletes were physically exhausted. These findings shed light on the conditions eliciting optimal use of sMI and dMI. In particular, considering that the current physical state affects body representation, performing dMI under fatigue may result in mismatches between actual and predicted body states.

  12. Coastal Bend Texas Benthic Habitat Mapping Reprocessed DOQQ Aerial Imagery (NODC Accession 0086051)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 2006 and 2007 the NOAA Coastal Services Center purchased services to reprocess existing digital multi-spectral imagery (ADS-40) and create digital benthic...

  13. Sleep-Related Improvements in Motor Learning Following Mental Practice

    Debarnot, Ursula; Creveaux, Thomas; Collet, Christian; Gemignani, Angelo; Massarelli, Raphael; Doyon, Julien; Guillot, Aymeric

    2009-01-01

    A wide range of experimental studies have provided evidence that a night of sleep may enhance motor performance following physical practice (PP), but little is known, however, about its effect after motor imagery (MI). Using an explicitly learned pointing task paradigm, thirty participants were assigned to one of three groups that differed in the…

  14. Imagery - Lake Ashtabula, ND - 2009 4-Band Orthophoto

    Army Corps of Engineers, Department of the Army, Department of Defense — 4-band aerial imagery was collected by Fugro Horizons using the Leica ADS40(SH52) camera with 30 percent side overlap on 8/26/09. The flight height was 9,600 feet...

  15. Mental imagery of speech implicates two mechanisms of perceptual reactivation.

    Tian, Xing; Zarate, Jean Mary; Poeppel, David

    2016-04-01

    Sensory cortices can be activated without any external stimuli. Yet, it is still unclear how this perceptual reactivation occurs and which neural structures mediate this reconstruction process. In this study, we employed fMRI with mental imagery paradigms to investigate the neural networks involved in perceptual reactivation. Subjects performed two speech imagery tasks: articulation imagery (AI) and hearing imagery (HI). We found that AI induced greater activity in frontal-parietal sensorimotor systems, including sensorimotor cortex, subcentral (BA 43), middle frontal cortex (BA 46) and parietal operculum (PO), whereas HI showed stronger activation in regions that have been implicated in memory retrieval: middle frontal (BA 8), inferior parietal cortex and intraparietal sulcus. Moreover, posterior superior temporal sulcus (pSTS) and anterior superior temporal gyrus (aSTG) was activated more in AI compared with HI, suggesting that covert motor processes induced stronger perceptual reactivation in the auditory cortices. These results suggest that motor-to-perceptual transformation and memory retrieval act as two complementary mechanisms to internally reconstruct corresponding perceptual outcomes. These two mechanisms can serve as a neurocomputational foundation for predicting perceptual changes, either via a previously learned relationship between actions and their perceptual consequences or via stored perceptual experiences of stimulus and episodic or contextual regularity. PMID:26889603

  16. Visual thinking & digital imagery

    Blevis, Eli; Churchill, Elizabeth; Odom, William; Pierre, James; Roedl, David; Wakkary, Ron

    2012-01-01

    This workshop focuses on exploring the centrality of visual literacy and visual thinking to HCI. Drawing on emerging critical perspectives, the workshop will address visual literacy and visual thinking from an interdisciplinary and transdisciplinary design-orientation [2, 8], foregrounding the notion that imagery is a primary form of visual thinking. Imagery—which subsumes digital imagery—goes well beyond sketching and beyond storyboards, screenshots and wireframes. We will address how a broa...

  17. Biomolecular motors

    Henry Hess

    2005-12-01

    Here, we give a brief introduction to molecular motors, with an emphasis on motor proteins, describe the challenges in interfacing these bionanomachines with an artificial environment, and provide examples of emerging applications.

  18. Visual imagery without visual perception?

    Helder Bértolo

    2005-01-01

    The question regarding visual imagery and visual perception remain an open issue. Many studies have tried to understand if the two processes share the same mechanisms or if they are independent, using different neural substrates. Most research has been directed towards the need of activation of primary visual areas during imagery. Here we review some of the works providing evidence for both claims. It seems that studying visual imagery in blind subjects can be us...

  19. Kinesthetic imagery of musical performance

    Martin eLotze

    2013-01-01

    Musicians use different kinds of imagery. This review focuses on kinesthetic imagery, which has been shown to be an effective complement to actively playing an instrument. However, experience in actual movement performance seems to be a requirement for a recruitment of those brain areas representing movement ideation during imagery. An internal model of movement performance might be more differentiated when training has been more intense or simply performed more often. Therefore, with respect...

  20. The use of technology-supported mental imagery in neurological rehabilitation: a research protocol.

    Morganti, Francesca; Gaggioli, Andrea; Castelnuovo, Gianluca; Bulla, Daniel; Vettorello, Marco; Riva, Giuseppe

    2003-08-01

    The human brain can simulate motor actions without physically executing them, and there is a neuro-psychological relationship between imaging and performing a movement. These are shared opinions. In fact there is scientific evidence showing that the mental simulation of an action is correlated to a subliminal activation of the motor system. There is also evidence that virtual stimulation can enhance the acquisition of simple motor sequences. In some situations, virtual training was found to be as beneficial as real training and more beneficial than workbook and no training in teaching complex motor skills to people with learning disabilities. Moreover, studies of brain-injured hemiplegics patients suggest that these patients retain the ability to generate accurate motor images even of actions that they cannot perform. Combined with evidence indicating that motor imagery and motor planning share common neural mechanisms, these observations suggest that supporting mental imagery through non-immersive, low-cost virtual reality (VR) applications may be a potentially effective intervention in the rehabilitation of brain-injured patients. Starting from this background, our goal is to design and develop a new technique for the acquisition of new motor abilities- "imagery enhanced learning" (or I-learning)-to be used in neuro-psychological rehabilitation. A key feature of I-learning is the use of potentially low-cost, Virtual Reality enhanced technology to facilitate motor imagery creating a compelling sense of presence. This paper will discuss the rationale and a preliminary rehabilitation protocol for investigating mental imagery as a means of promoting motor recovery in patients with a neurological disorder. The treatment strategy aims at evoking powerful imaginative responses using an innovative technique which makes no attempt to simulate the real-world motor behavior, but draws the patient's attention to its underlying dynamic structure. This is done by displaying

  1. Imagery Rescripting for Personality Disorders

    Arntz, Arnoud

    2011-01-01

    Imagery rescripting is a powerful technique that can be successfully applied in the treatment of personality disorders. For personality disorders, imagery rescripting is not used to address intrusive images but to change the implicational meaning of schemas and childhood experiences that underlie the patient's problems. Various mechanisms that may…

  2. Guided Imagery in Career Awareness.

    Wilson, William C.; Eddy, John

    1982-01-01

    Suggests guided imagery can stimulate clients to become more aware of the role of personal values, attitudes, and beliefs in career decision making. Presents guidelines, examples, and implications to enable rehabilitation counselors to use guided imagery exercises in career counseling. (Author)

  3. Playing piano in the mind--an fMRI study on music imagery and performance in pianists.

    Meister, I G; Krings, T; Foltys, H; Boroojerdi, B; Müller, M; Töpper, R; Thron, A

    2004-05-01

    Reading of musical notes and playing piano is a very complex motor task which requires years of practice. In addition to motor skills, rapid and effective visuomotor transformation as well as processing of the different components of music like pitch, rhythm and musical texture are involved. The aim of the present study was the investigation of the cortical network which mediates music performance compared to music imagery in 12 music academy students playing the right hand part of a Bartok piece using functional magnetic resonance imaging (fMRI). In both conditions, fMRI activations of a bilateral frontoparietal network comprising the premotor areas, the precuneus and the medial part of Brodmann Area 40 were found. During music performance but not during imagery the contralateral primary motor cortex and posterior parietal cortex (PPC) bilaterally was active. This reflects the role of primary motor cortex for motor execution but not imagery and the higher visuomotor integration requirements during music performance compared to simulation. The notion that the same areas are involved in visuomotor transformation/motor planning and music processing emphasizes the multimodal properties of cortical areas involved in music and motor imagery in musicians. PMID:15062860

  4. Motor neglect.

    Laplane, D.; Degos, J D

    1983-01-01

    Motor neglect is characterised by an underutilisation of one side, without defects of strength, reflexes or sensibility. Twenty cases of frontal, parietal and thalamic lesions causing motor neglect, but all without sensory neglect, are reported. It is proposed that the cerebral structures involved in motor neglect are the same as those for sensory neglect and for the preparation of movement. As in sensory neglect, the multiplicity of the structures concerned suggests that this interconnection...

  5. Motor syndromes.

    Corea, Francesco; Micheli, Sara

    2012-01-01

    Motor disturbances alone or associated with other focal deficits are the most common symptoms suggesting a neurovascular event. An appropriate clinical assessment of these signs and symptoms may help physicians to better diagnose and to both better treat and predict outcome. In this paper the main clinical features of motor deficit are described together with other motor-related events such as ataxia and movement disturbances. PMID:22377850

  6. Online Ad Assignment with an Ad Exchange

    Dvořák, Wolfgang; Henzinger, Monika

    2016-01-01

    Ad exchanges are becoming an increasingly popular way to sell advertisement slots on the internet. An ad exchange is basically a spot market for ad impressions. A publisher who has already signed contracts reserving advertisement impressions on his pages can choose between assigning a new ad impression for a new page view to a contracted advertiser or to sell it at an ad exchange. This leads to an online revenue maximization problem for the publisher. Given a new impression to sell decide whe...

  7. Watch me if you can: imagery ability moderates observational learning effectiveness

    Gavin eLawrence; Nichola eCallow; Ross eRoberts

    2013-01-01

    Recent research has revealed similarities in brain activity during observational learning and motor execution. However, whilst action develops visual, motor and afferent representations during acquisition, action-observation has been proposed to only develop visual-spatial learning via visual representation. In addition, it has been suggested that the vividness of visual representations are determined by imagery ability. Thus, the purpose of the current investigation was to explore the possib...

  8. Two AdS2 branes in the euclidean AdS3

    We compute the density of open strings stretching between AdS2 branes in the euclidean AdS3. This is done by solving the factorization constraint of a degenerate boundary field, and the result is checked by a Cardy-type computation. We mention applications to branes in the minkowskian AdS3 and its cigar coset. (author)

  9. Two AdS2 branes in the Euclidean AdS3

    Ribault, S

    2003-01-01

    We compute the density of open strings stretching between AdS2 branes in the Euclidean AdS3. This is done by solving the factorization constraint of a degenerate boundary field, and the result is checked by a Cardy-type computation. We mention applications to branes in the Minkowskian AdS3 and its cigar coset.

  10. APFO Historical Availability of Imagery

    Farm Service Agency, Department of Agriculture — The APFO Historical Availability ArcGIS Online web map provides an easy to use reference of what historical imagery is available by county from the Aerial...

  11. Dynamic aspects of musical imagery.

    Halpern, Andrea R

    2012-04-01

    Auditory imagery can represent many aspects of music, such as the starting pitches of a tune or the instrument that typically plays it. In this paper, I concentrate on more dynamic, or time-sensitive aspects of musical imagery, as demonstrated in two recently published studies. The first was a behavioral study that examined the ability to make emotional judgments about both heard and imagined music in real time. The second was a neuroimaging study on the neural correlates of anticipating an upcoming tune, after hearing a cue tune. That study found activation of several sequence-learning brain areas, some of which varied with the vividness of the anticipated musical memory. Both studies speak to the ways in which musical imagery allows us to judge temporally changing aspects of the represented musical experience. These judgments can be quite precise, despite the complexity of generating the rich internal representations of imagery. PMID:22524360

  12. Health-related ad information and health motivation effects on product evaluations

    Chrysochou, Polymeros; Grunert, Klaus G

    2014-01-01

    This study tests the effect of health-related ad information on perceived product healthfulness and purchase intention. Also, the study investigates whether consumers' health motivation moderates the effects, because of the way health motivation affects processing of health-related information...... in ads. Three types of healthrelated ad elements are distinguished: functional claims, process claims and health imagery. These elements were combined in mock ads and an online experiment was run to test the study hypotheses. Results show that health imagery has the largest impact on consumers' product...

  13. Investigating the effects of a sensorimotor rhythm-based BCI training on the cortical activity elicited by mental imagery

    Toppi, J.; Risetti, M.; Quitadamo, L. R.; Petti, M.; Bianchi, L.; Salinari, S.; Babiloni, F.; Cincotti, F.; Mattia, D.; Astolfi, L.

    2014-06-01

    Objective. It is well known that to acquire sensorimotor (SMR)-based brain-computer interface (BCI) control requires a training period before users can achieve their best possible performances. Nevertheless, the effect of this training procedure on the cortical activity related to the mental imagery ability still requires investigation to be fully elucidated. The aim of this study was to gain insights into the effects of SMR-based BCI training on the cortical spectral activity associated with the performance of different mental imagery tasks. Approach. Linear cortical estimation and statistical brain mapping techniques were applied on high-density EEG data acquired from 18 healthy participants performing three different mental imagery tasks. Subjects were divided in two groups, one of BCI trained subjects, according to their previous exposure (at least six months before this study) to motor imagery-based BCI training, and one of subjects who were naive to any BCI paradigms. Main results. Cortical activation maps obtained for trained and naive subjects indicated different spectral and spatial activity patterns in response to the mental imagery tasks. Long-term effects of the previous SMR-based BCI training were observed on the motor cortical spectral activity specific to the BCI trained motor imagery task (simple hand movements) and partially generalized to more complex motor imagery task (playing tennis). Differently, mental imagery with spatial attention and memory content could elicit recognizable cortical spectral activity even in subjects completely naive to (BCI) training. Significance. The present findings contribute to our understanding of BCI technology usage and might be of relevance in those clinical conditions when training to master a BCI application is challenging or even not possible.

  14. Motor homopolar

    2007-01-01

    Mostramos la construcción de un modelo de motor homopolar, uno de los más antiguos tipos de motores eléctricos. Se caracterizan porque el campo magnético del imán mantiene siempre la misma polaridad (de ahí su nombre, del griego homos, igual), de modo que, cuando una corriente eléctrica atraviesa el campo magnético, aparece una fuerza que hace girar los elementos no fijados mecánicamente. En el sencillísimo motor homopolar colgado (Schlichting y Ucke 2004), el imán puede girar ...

  15. Predictive models to determine imagery strategies employed by children to judge hand laterality.

    Steffie Spruijt

    Full Text Available A commonly used paradigm to study motor imagery is the hand laterality judgment task. The present study aimed to determine which strategies young children employ to successfully perform this task. Children of 5 to 8 years old (N = 92 judged laterality of back and palm view hand pictures in different rotation angles. Response accuracy and response duration were registered. Response durations of the trials with a correct judgment were fitted to a-priori defined predictive sinusoid models, representing different strategies to successfully perform the hand laterality judgment task. The first model predicted systematic changes in response duration as a function of rotation angle of the displayed hand. The second model predicted that response durations are affected by biomechanical constraints of hand rotation. If observed data could be best described by the first model, this would argue for a mental imagery strategy that does not involve motor processes to solve the task. The second model reflects a motor imagery strategy to solve the task. In line with previous research, we showed an age-related increase in response accuracy and decrease in response duration in children. Observed data for both back and palm view showed that motor imagery strategies were used to perform hand laterality judgments, but that not all the children use these strategies (appropriately at all times. A direct comparison of response duration patterns across age sheds new light on age-related differences in the strategies employed to solve the task. Importantly, the employment of the motor imagery strategy for successful task performance did not change with age.

  16. Electroencephalogram processing in Motor Imagery Based BCI: A tutorial

    Garcia Molina, G.

    2008-01-01

    Brain-computer interfaces (BCIs) have been emerging during the last twenty years, as plausible alternatives for offering communication and control to physically challenged people. Yet, the idea of achieving control by simply thinking is appealing to a wider range of users. Availability, lower cost,

  17. Application of stepping motor

    This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.

  18. AdS solutions through transgression

    We present new classes of explicit supersymmetric AdS3 solutions of type IIB supergravity with non-vanishing five-form flux and AdS2 solutions of D=11 supergravity with electric four-form flux. The former are dual to two-dimensional SCFTs with (0,2) supersymmetry and the latter to supersymmetric quantum mechanics with two supercharges. We also investigate more general classes of AdS3 solutions of type IIB supergravity and AdS2 solutions of D=11 supergravity which in addition have non-vanishing three-form flux and magnetic four-form flux, respectively. The construction of these more general solutions makes essential use of the Chern-Simons or ''transgression'' terms in the Bianchi identity or the equation of motion of the field strengths in the supergravity theories. We construct infinite new classes of explicit examples and for some of the type IIB solutions determine the central charge of the dual SCFTs. The type IIB solutions with non-vanishing three-form flux that we construct include a two-torus, and after two T-dualities and an S-duality, we obtain new AdS3 solutions with only the NS fields being non-trivial. (orig.)

  19. Polarised Black Holes in AdS

    Costa, Miguel S; Oliveira, Miguel; Penedones, João; Santos, Jorge E

    2015-01-01

    We consider solutions in Einstein-Maxwell theory with a negative cosmological constant that asymptote to global $AdS_{4}$ with conformal boundary $S^{2}\\times\\mathbb{R}_{t}$. At the sphere at infinity we turn on a space-dependent electrostatic potential, which does not destroy the asymptotic $AdS$ behaviour. For simplicity we focus on the case of a dipolar electrostatic potential. We find two new geometries: (i) an $AdS$ soliton that includes the full backreaction of the electric field on the $AdS$ geometry; (ii) a polarised neutral black hole that is deformed by the electric field, accumulating opposite charges in each hemisphere. For both geometries we study boundary data such as the charge density and the stress tensor. For the black hole we also study the horizon charge density and area, and further verify a Smarr formula. Then we consider this system at finite temperature and compute the Gibbs free energy for both $AdS$ soliton and black hole phases. The corresponding phase diagram generalizes the Hawkin...

  20. Common Ground Station For Imagery Processing And Exploitation

    Johnston, Morris V.

    1989-02-01

    a minimum number of deployable shelters. Primary imagery inputs are from Tactical and National sources. The system provides all processing necessary to support both softcopy and hardcopy imagery exploitation. The system design is expandable, contractible, modular and segmentable. Modularity consists of packaging segments in functional units so they may be added or deleted when and where required to meet specific user requirements. Segmentability is achieved by allocating system requirements to a single functional area known as a segment. The design uses off-the-shelf hardware and software where practical and cost effective. The System is capable of operating either in a stand-alone mode while deployed or while tethered to and supporting fixed intelligence facilities. Each segment provides all functions and capabilties needed to satisfy the performance requirements for that segment. Functional and physical interface documents define the exchange of information and data between segments and with external systems. To enhance future Pre-Planned Product Improvements (P3I), the architecture promotes technology transparency within JSIPS through bus type structures. Evolutionary development allows for emerging sensors and platforms to be accommodated by substituting or adding a minimum number of plug-in hardware or software interface modules to an operational production model. Technology transparency allows for incorporation of new technologies as they become available.

  1. Baby Skyrmions in AdS

    Elliot-Ripley, Matthew; Winyard, Thomas

    2015-01-01

    We study the baby Skyrme model in a pure AdS background without a mass term. The tail decays and scalings of massless radial solutions are demonstrated to take a similar form to those of the massive flat space model, with the AdS curvature playing a similar role to the flat space pion mass. We also numerically find minimal energy solutions for a range of higher topological charges and find that they form concentric ring-like solutions. Popcorn transitions (named in analogy with studies of toy...

  2. When that tune runs through your head: a PET investigation of auditory imagery for familiar melodies.

    Halpern, A R; Zatorre, R J

    1999-01-01

    The present study used positron emission tomography (PET) to examine the cerebral activity pattern associated with auditory imagery for familiar tunes. Subjects either imagined the continuation of nonverbal tunes cued by their first few notes, listened to a short sequence of notes as a control task, or listened and then reimagined that short sequence. Subtraction of the activation in the control task from that in the real-tune imagery task revealed primarily right-sided activation in frontal and superior temporal regions, plus supplementary motor area (SMA). Isolating retrieval of the real tunes by subtracting activation in the reimagine task from that in the real-tune imagery task revealed activation primarily in right frontal areas and right superior temporal gyrus. Subtraction of activation in the control condition from that in the reimagine condition, intended to capture imagery of unfamiliar sequences, revealed activation in SMA, plus some left frontal regions. We conclude that areas of right auditory association cortex, together with right and left frontal cortices, are implicated in imagery for familiar tunes, in accord with previous behavioral, lesion and PET data. Retrieval from musical semantic memory is mediated by structures in the right frontal lobe, in contrast to results from previous studies implicating left frontal areas for all semantic retrieval. The SMA seems to be involved specifically in image generation, implicating a motor code in this process. PMID:10554992

  3. Visual imagery without visual perception?

    Helder Bértolo

    2005-01-01

    Full Text Available The question regarding visual imagery and visual perception remain an open issue. Many studies have tried to understand if the two processes share the same mechanisms or if they are independent, using different neural substrates. Most research has been directed towards the need of activation of primary visual areas during imagery. Here we review some of the works providing evidence for both claims. It seems that studying visual imagery in blind subjects can be used as a way of answering some of those questions, namely if it is possible to have visual imagery without visual perception. We present results from the work of our group using visual activation in dreams and its relation with EEG’s spectral components, showing that congenitally blind have visual contents in their dreams and are able to draw them; furthermore their Visual Activation Index is negatively correlated with EEG alpha power. This study supports the hypothesis that it is possible to have visual imagery without visual experience.

  4. Short-Term Limb Immobilization Affects Cognitive Motor Processes

    Toussaint, Lucette; Meugnot, Aurore

    2013-01-01

    We examined the effects of a brief period of limb immobilization on the cognitive level of action control. A splint placed on the participants' left hand was used as a means of immobilization. We used a hand mental rotation task to investigate the immobilization-induced effects on motor imagery performance (Experiments 1 and 2) and a number mental…

  5. Mental imagery of speech and movement implicates the dynamics of internal forward models

    Xing eTian

    2010-10-01

    Full Text Available The classical concept of efference copies in the context of internal forward models has stimulated productive research in cognitive science and neuroscience. There are compelling reasons to argue for such a mechanism, but finding direct evidence in the human brain remains difficult. Here we investigate the dynamics of internal forward models from an unconventional angle: mental imagery, assessed while recording high temporal resolution neuronal activity using magnetoencephalography (MEG. We compare two overt and covert tasks; our covert, mental imagery tasks are unconfounded by overt input/output demands – but in turn necessitate the development of appropriate multi-dimensional topographic analyses. Finger tapping (studies 1-2 and speech experiments (studies 3-5 provide temporally constrained results that implicate the estimation of an efference copy. We suggest that one internal forward model over parietal cortex subserves the kinesthetic feeling in motor imagery. Secondly, observed auditory neural activity ~170 ms after motor estimation in speech experiments (studies 3-5 demonstrates the anticipated auditory consequences of planned motor commands in a second internal forward model in imagery of speech production. Our results provide neurophysiological evidence from the human brain in favor of internal forward models deploying efference copies in somatosensory and auditory cortex, in finger tapping and speech production tasks, respectively, and also suggest the dynamics and sequential updating structure of internal forward models.

  6. Eternal Black Holes in AdS

    Maldacena, Juan M.

    2001-01-01

    We propose a dual non-perturbative description for maximally extended Schwarzschild Anti-de-Sitter spacetimes. The description involves two copies of the conformal field theory associated to the AdS spacetime and an initial entangled state. In this context we also discuss a version of the information loss paradox and its resolution.

  7. AdS braneworld with Backreaction

    Bilić Neven; Tupper Gary

    2013-01-01

    We review the tachyon model derived from the dynamics of a 3-brane moving in the AdS5 bulk. The bulk geometry is based on the Randall-Sundrum II model extended to include the radion. The effective tachyon Lagrangian is modified due to the back-reaction of the brane on the bulk geometry.

  8. Current status of AdS instability

    CERN. Geneva

    2016-01-01

    arXiv:1403.6471 and thoroughly developed in arXiv:1407.6273. On the other hand the negative cosmological constant allows for the existence of stable, time-periodic, asymptotically AdS solutions of Einstein equations [arXiv:1303.3186].

  9. AdS braneworld with Backreaction

    Bilic, Neven

    2014-01-01

    We review the tachyon model derived from the dynamics of a 3-brane moving in the AdS5 bulk. The bulk geometry is based on the Randall-Sundrum II model extended to include the radion. The effective tachyon Lagrangian is modified due to the back-reaction of the brane on the bulk geometry.

  10. Publicly Available IKONOS-2 Commercial Imagery

    U.S. Geological Survey, Department of the Interior — The USGS Commercial Data Purchases (UCDP) imagery collection is an archive of commercial remote sensing imagery from several different commercial vendors. The UCDP...