Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146595
R. Ortner, J. Scharinger, A. Lechner, C. Guger
EEG based Brain-Computer Interfaces (BCIs) often use evoked potentials (P300), steady state visual evoked potentials (SSVEP) or motor imagery (MI) for control strategies. This study investigated maximum and mean accuracy of a MI based BCI using Common Spatial Patterns (CSP). Twenty healthy people participated in the study and were equipped with 64 active EEG electrodes. They performed a training paradigm with 160 trials by imagining either left or right hand movement to set up a subject specific CSP filter to spatially filter the EEG data. Following that, two real-time runs with 80 trials were performed, which provided feedback to the subject. The real-time accuracy was then calculated for every subject, and finally a grand average accuracy of 80.7% was reached for the 20 subjects. One person reached a perfect classification result of 100%, 30% performed above 90% and one was below 59%. The results show that most people can use a MI based BCI after a brief training time if CSPs with 64 active electrodes are used. The method of CSP yields clearly better classification results compared to a bandpower approach. While more electrodes are needed for classification, this is less of a disadvantage with modern active electrodes.
{"title":"How many people can control a motor imagery based BCI using common spatial patterns?","authors":"R. Ortner, J. Scharinger, A. Lechner, C. Guger","doi":"10.1109/NER.2015.7146595","DOIUrl":"https://doi.org/10.1109/NER.2015.7146595","url":null,"abstract":"EEG based Brain-Computer Interfaces (BCIs) often use evoked potentials (P300), steady state visual evoked potentials (SSVEP) or motor imagery (MI) for control strategies. This study investigated maximum and mean accuracy of a MI based BCI using Common Spatial Patterns (CSP). Twenty healthy people participated in the study and were equipped with 64 active EEG electrodes. They performed a training paradigm with 160 trials by imagining either left or right hand movement to set up a subject specific CSP filter to spatially filter the EEG data. Following that, two real-time runs with 80 trials were performed, which provided feedback to the subject. The real-time accuracy was then calculated for every subject, and finally a grand average accuracy of 80.7% was reached for the 20 subjects. One person reached a perfect classification result of 100%, 30% performed above 90% and one was below 59%. The results show that most people can use a MI based BCI after a brief training time if CSPs with 64 active electrodes are used. The method of CSP yields clearly better classification results compared to a bandpower approach. While more electrodes are needed for classification, this is less of a disadvantage with modern active electrodes.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121989822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146737
Reva E. Johnson, Konrad Paul Kording, L. Hargrove, J. Sensinger
EMG control of powered upper limb prostheses is difficult and imprecise. One approach for improving control is to help amputees develop more accurate internal models of their prosthetic device. This may be facilitated by an intuitive mapping of neural signals to device movement, a way of providing sensory feedback, or training methods. A first step, arguably, is to understand how an amputation affects adaptation. Here we studied trial-by-trial adaptation in a simple target-directed task with transhumeral amputees and healthy controls. We found that adaptation behavior was indistinguishable between amputees using the residual limb, amputees using the intact limb, and able-bodied subjects. Transhumeral amputees completed the task with larger errors than able-bodied subjects, but there was, perhaps surprisingly, no difference between the residual and intact limb.
{"title":"Similar trial-by-trial adaptation behavior across transhumeral amputees and able-bodied subjects","authors":"Reva E. Johnson, Konrad Paul Kording, L. Hargrove, J. Sensinger","doi":"10.1109/NER.2015.7146737","DOIUrl":"https://doi.org/10.1109/NER.2015.7146737","url":null,"abstract":"EMG control of powered upper limb prostheses is difficult and imprecise. One approach for improving control is to help amputees develop more accurate internal models of their prosthetic device. This may be facilitated by an intuitive mapping of neural signals to device movement, a way of providing sensory feedback, or training methods. A first step, arguably, is to understand how an amputation affects adaptation. Here we studied trial-by-trial adaptation in a simple target-directed task with transhumeral amputees and healthy controls. We found that adaptation behavior was indistinguishable between amputees using the residual limb, amputees using the intact limb, and able-bodied subjects. Transhumeral amputees completed the task with larger errors than able-bodied subjects, but there was, perhaps surprisingly, no difference between the residual and intact limb.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116862896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146562
Dimitra Makri, C. Farmaki, V. Sakkalis
Brain computer interfaces are a direct communication pathway between the brain and external devices and require mental effort to work efficiently. After long use of such interfacing systems, subjects have reported fatigue symptoms. Fatigue influence on the EEG signals could disrupt human-computer communication and decrease the reliability of the responses. In this paper, fatigue effects on SSVEP-based BCI use are evaluated. Thirteen healthy subjects participated in the experiment, which uses a BCI system originally designed for online wheelchair navigation. Signal analysis was based on accuracy rates, band power spectra and SSVEP amplitudes extraction. Although accuracy levels show no statistically significant differences, self-reported fatigue levels increase and SSVEP amplitudes decrease with time. Our analysis demonstrates no consistent band power changes.
{"title":"Visual fatigue effects on Steady State Visual Evoked Potential-based Brain Computer Interfaces","authors":"Dimitra Makri, C. Farmaki, V. Sakkalis","doi":"10.1109/NER.2015.7146562","DOIUrl":"https://doi.org/10.1109/NER.2015.7146562","url":null,"abstract":"Brain computer interfaces are a direct communication pathway between the brain and external devices and require mental effort to work efficiently. After long use of such interfacing systems, subjects have reported fatigue symptoms. Fatigue influence on the EEG signals could disrupt human-computer communication and decrease the reliability of the responses. In this paper, fatigue effects on SSVEP-based BCI use are evaluated. Thirteen healthy subjects participated in the experiment, which uses a BCI system originally designed for online wheelchair navigation. Signal analysis was based on accuracy rates, band power spectra and SSVEP amplitudes extraction. Although accuracy levels show no statistically significant differences, self-reported fatigue levels increase and SSVEP amplitudes decrease with time. Our analysis demonstrates no consistent band power changes.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124968194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146574
Yufeng Ke, Peiyuan Wang, Yuqian Chen, Bin Gu, Hongzhi Qi, Peng Zhou, Dong Ming
Being one of the most popular and extensively studied ERP-BCI paradigm, ERP-spellers are commonly built and tested in ideal lab settings. However, in practical applications, users may encounter complex situations and various mental processing that have been believed to affect ERP signals. This kind of effect will probably induce a deteriorated performance of ERP-spellers. In the current study, a working memory task was interleaved within an RC ERP-speller paradigm to examine the effect of concurrent mental processing both on ERPs evoked by the stimuli of speller and its performance, especially when a speller is built under pure lab setting but used under complex mental activities in real life. The results show that the amplitude of N200, P360 and N550 were significantly affected by the working memory task. Moreover, the performance of ERP-spellers was significantly deteriorated by concurrently performing a working memory task, not only when a speller is trained and used in different settings, but also when a speller is both built and used in the same complex setting. These findings introduce a challenge for ERP-spellers to be used outside lab-settings and in daily work, especially when users are undergoing complex mental processing and experiencing heavy mental workload.
{"title":"Concurrent mental activities affect ERPs and impair performance of ERP-spellers","authors":"Yufeng Ke, Peiyuan Wang, Yuqian Chen, Bin Gu, Hongzhi Qi, Peng Zhou, Dong Ming","doi":"10.1109/NER.2015.7146574","DOIUrl":"https://doi.org/10.1109/NER.2015.7146574","url":null,"abstract":"Being one of the most popular and extensively studied ERP-BCI paradigm, ERP-spellers are commonly built and tested in ideal lab settings. However, in practical applications, users may encounter complex situations and various mental processing that have been believed to affect ERP signals. This kind of effect will probably induce a deteriorated performance of ERP-spellers. In the current study, a working memory task was interleaved within an RC ERP-speller paradigm to examine the effect of concurrent mental processing both on ERPs evoked by the stimuli of speller and its performance, especially when a speller is built under pure lab setting but used under complex mental activities in real life. The results show that the amplitude of N200, P360 and N550 were significantly affected by the working memory task. Moreover, the performance of ERP-spellers was significantly deteriorated by concurrently performing a working memory task, not only when a speller is trained and used in different settings, but also when a speller is both built and used in the same complex setting. These findings introduce a challenge for ERP-spellers to be used outside lab-settings and in daily work, especially when users are undergoing complex mental processing and experiencing heavy mental workload.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"2013 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127434392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146604
A. Zabihian, A. M. Sodagar, M. Sawan
New high-performance neural interfacing approaches are demanded for today's Brain-Machine Interfaces (BMIs). In this paper, we present the architecture of a wireless network of implantable microsystems (Brain-ASNET: Brain Area Sensor NETwork). As well, we introduce an energy-efficient ad-hoc network protocol for the desired network, along with a method to overcome issue of variable packet length caused by bit stuffing process in HDLC standard protocol. To implement the idea, architecture and design of a System-on-a-Chip (SoC) is also presented. The SoC can be configured to be used either as a sensor node chip or the network coordinator's RF front-end and network controller. The SoC is designed and laid-out in an IBM 0.13μm CMOS process. The post-layout simulation results show energy efficiency of the designed ad-hoc network protocol and low power dissipation of the SoC. The whole chip, including all functional and peripheral integrated components, consumes 138μW and 412μW, at 1.2V, configured in a synchronized network as a sensor node and the coordinator, respectively.
{"title":"Distributed Intracortical Neural Interfacing: Network protocol design","authors":"A. Zabihian, A. M. Sodagar, M. Sawan","doi":"10.1109/NER.2015.7146604","DOIUrl":"https://doi.org/10.1109/NER.2015.7146604","url":null,"abstract":"New high-performance neural interfacing approaches are demanded for today's Brain-Machine Interfaces (BMIs). In this paper, we present the architecture of a wireless network of implantable microsystems (Brain-ASNET: Brain Area Sensor NETwork). As well, we introduce an energy-efficient ad-hoc network protocol for the desired network, along with a method to overcome issue of variable packet length caused by bit stuffing process in HDLC standard protocol. To implement the idea, architecture and design of a System-on-a-Chip (SoC) is also presented. The SoC can be configured to be used either as a sensor node chip or the network coordinator's RF front-end and network controller. The SoC is designed and laid-out in an IBM 0.13μm CMOS process. The post-layout simulation results show energy efficiency of the designed ad-hoc network protocol and low power dissipation of the SoC. The whole chip, including all functional and peripheral integrated components, consumes 138μW and 412μW, at 1.2V, configured in a synchronized network as a sensor node and the coordinator, respectively.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130098875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146817
L. S. Fernandes, D. Ferreira, P. Almeida, N. Dias
As the brain ages, it suffers several neurochemical, structural and functional changes. These deficits are primarily reflected on daily memory tasks. In the present work, we use the Wisconsin Card Sorting Task (WCST) task to assess P300 component of the event-related potential (ERP) as a marker for aging. Considering age-related effects, WCST was applied to young, middle-aged and elder participants. Early-late trial analysis tested the attentional set shifting and working memory updating hypothesis for the mechanisms behind WCST. The results suggest that, as people age, P3b peak latency highly correlates with age on both early and late trials, increasing as people gets older. P3b peak amplitude significantly distinguished between early and late trials regardless the subjects' age, while there were no differences on P300 peak latency.
{"title":"Aging and attentional set shifting on WCST: An event-related EEG study","authors":"L. S. Fernandes, D. Ferreira, P. Almeida, N. Dias","doi":"10.1109/NER.2015.7146817","DOIUrl":"https://doi.org/10.1109/NER.2015.7146817","url":null,"abstract":"As the brain ages, it suffers several neurochemical, structural and functional changes. These deficits are primarily reflected on daily memory tasks. In the present work, we use the Wisconsin Card Sorting Task (WCST) task to assess P300 component of the event-related potential (ERP) as a marker for aging. Considering age-related effects, WCST was applied to young, middle-aged and elder participants. Early-late trial analysis tested the attentional set shifting and working memory updating hypothesis for the mechanisms behind WCST. The results suggest that, as people age, P3b peak latency highly correlates with age on both early and late trials, increasing as people gets older. P3b peak amplitude significantly distinguished between early and late trials regardless the subjects' age, while there were no differences on P300 peak latency.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129111191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146603
S. Ktena, W. Abbott, A. Faisal
The importance of ensuring user safety throughout the training and evaluation process of brain-machine interfaces is not to be neglected. In this study, a virtual reality software system was built with the intention to create a safe environment, where the performance of wheelchair control interfaces could be tested and compared. We use this to evaluate our eye tracking input methodology, a promising solution for hands-free wheelchair navigation, because of the abundance of control commands that it offers and its intuitive nature. Natural eye movements have long been considered to reflect cognitive processes and are highly correlated with user intentions. Therefore, the sequence of gaze locations during navigation is recorded and analyzed, in order to search and unveil patterns in saccadic movements. Moreover, this study compares different eye-based solutions that have previously been implemented, and proposes a new, more natural approach. The preliminary results on N = 6 healthy subjects indicate that the proposed free-view solution leads to 18.4% faster completion of the task (440 sec) benchmarked against a naive free-view approach.
{"title":"A virtual reality platform for safe evaluation and training of natural gaze-based wheelchair driving","authors":"S. Ktena, W. Abbott, A. Faisal","doi":"10.1109/NER.2015.7146603","DOIUrl":"https://doi.org/10.1109/NER.2015.7146603","url":null,"abstract":"The importance of ensuring user safety throughout the training and evaluation process of brain-machine interfaces is not to be neglected. In this study, a virtual reality software system was built with the intention to create a safe environment, where the performance of wheelchair control interfaces could be tested and compared. We use this to evaluate our eye tracking input methodology, a promising solution for hands-free wheelchair navigation, because of the abundance of control commands that it offers and its intuitive nature. Natural eye movements have long been considered to reflect cognitive processes and are highly correlated with user intentions. Therefore, the sequence of gaze locations during navigation is recorded and analyzed, in order to search and unveil patterns in saccadic movements. Moreover, this study compares different eye-based solutions that have previously been implemented, and proposes a new, more natural approach. The preliminary results on N = 6 healthy subjects indicate that the proposed free-view solution leads to 18.4% faster completion of the task (440 sec) benchmarked against a naive free-view approach.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128899292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146685
A. Ang, Zhiguo Zhang, Y. Hung, J. Mak
This paper presents a novel wearable single-channel electrooculography (EOG) based human-computer interface (HCI) with a simple system design and robust performance. In the proposed system, EOG signals for control are generated from double eye blinks, collected by a commercial wearable device (the NeuroSky MindWave headset), and then converted into a sequence of commands that can control cursor navigations and actions. The EOG-based cursor control system was tested on 8 subjects in indoor or outdoor environment, and the average accuracy is 84.42% for indoor uses and 71.50% for outdoor uses. Compared with other existing EOG-based HCI systems, this system is highly user-friendly and does not require any training. Therefore, this system has the potential to provide an easy-to-use and cheap assistive technique for locked-in patients who have lost their main body muscular abilities but with proper eye-condition.
{"title":"A user-friendly wearable single-channel EOG-based human-computer interface for cursor control","authors":"A. Ang, Zhiguo Zhang, Y. Hung, J. Mak","doi":"10.1109/NER.2015.7146685","DOIUrl":"https://doi.org/10.1109/NER.2015.7146685","url":null,"abstract":"This paper presents a novel wearable single-channel electrooculography (EOG) based human-computer interface (HCI) with a simple system design and robust performance. In the proposed system, EOG signals for control are generated from double eye blinks, collected by a commercial wearable device (the NeuroSky MindWave headset), and then converted into a sequence of commands that can control cursor navigations and actions. The EOG-based cursor control system was tested on 8 subjects in indoor or outdoor environment, and the average accuracy is 84.42% for indoor uses and 71.50% for outdoor uses. Compared with other existing EOG-based HCI systems, this system is highly user-friendly and does not require any training. Therefore, this system has the potential to provide an easy-to-use and cheap assistive technique for locked-in patients who have lost their main body muscular abilities but with proper eye-condition.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132892609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146612
Tiwalade Sobayo, D. Mogul
Deep brain stimulation (DBS) is a potentially potent means for disrupting the aberrant rhythms that arise during a seizure. However, current DBS strategies typically employed are formulated a priori and do not reflect dynamics within the brain during ictogenesis which may severely limit stimulation efficacy. This study investigated how DBS could be improved using endogenous dynamics to inform stimulation protocols. Multi-site brain dynamics within the circuit of Papez was calculated in a chronic rat limbic epilepsy model. Stimulation/recording electrodes were placed in the CA3 region of both hippocampi and in the anteromedial nucleus of the thalamus. Deconvolution of signals using empirical mode decomposition and coherence analysis were used to identify key dynamics as seizures progressed. Synchronization of field potentials across sites occurred as both spontaneous and evoked seizures naturally terminated. The location and frequency of synchrony varied between subjects suggesting that endogenous rhythms during natural seizure termination may vary in humans as well. DBS efficacy was significantly more effective at stopping seizures when the frequency of multisite synchronized stimulation reflected endogenous synchrony dynamics observed in each subject. Thus, tailoring DBS protocols to individual endogenous rhythms that may represent how brains naturally resolve epileptic seizures could play a critical role in improving overall efficacy of this potentially important therapy.
{"title":"Deep brain stimulation protocols that mirror endogenous rhythms show increased efficacy at terminating seizures","authors":"Tiwalade Sobayo, D. Mogul","doi":"10.1109/NER.2015.7146612","DOIUrl":"https://doi.org/10.1109/NER.2015.7146612","url":null,"abstract":"Deep brain stimulation (DBS) is a potentially potent means for disrupting the aberrant rhythms that arise during a seizure. However, current DBS strategies typically employed are formulated a priori and do not reflect dynamics within the brain during ictogenesis which may severely limit stimulation efficacy. This study investigated how DBS could be improved using endogenous dynamics to inform stimulation protocols. Multi-site brain dynamics within the circuit of Papez was calculated in a chronic rat limbic epilepsy model. Stimulation/recording electrodes were placed in the CA3 region of both hippocampi and in the anteromedial nucleus of the thalamus. Deconvolution of signals using empirical mode decomposition and coherence analysis were used to identify key dynamics as seizures progressed. Synchronization of field potentials across sites occurred as both spontaneous and evoked seizures naturally terminated. The location and frequency of synchrony varied between subjects suggesting that endogenous rhythms during natural seizure termination may vary in humans as well. DBS efficacy was significantly more effective at stopping seizures when the frequency of multisite synchronized stimulation reflected endogenous synchrony dynamics observed in each subject. Thus, tailoring DBS protocols to individual endogenous rhythms that may represent how brains naturally resolve epileptic seizures could play a critical role in improving overall efficacy of this potentially important therapy.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"283 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132093057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-22DOI: 10.1109/NER.2015.7146647
Joshua Chang, D. Paydarfar
Computing the average input stimulus preceding a spike, the spike-triggered average (STA), has been a powerful tool for discovering a neuron's `preferred' stimulus feature that enables efficient encoding of sensory information. Recent work in the squid giant axon has shown that STA waveforms can be remarkably similar to the energetically optimal stimulus waveforms for eliciting a spike. In the present study, we show using the Hodgkin-Huxley model that the STA can deviate from the global optimal solution if there is averaging of multiple solutions across different time scales and of multiple modes of spike induction. These findings inform attempts to develop model-free stochastic algorithms for finding energy-optimal stimuli, which is relevant to the efficient delivery of exogenous therapeutic stimuli in neurological diseases.
{"title":"Optimal stimulus waveforms for eliciting a spike: How close is the spike-triggered average?","authors":"Joshua Chang, D. Paydarfar","doi":"10.1109/NER.2015.7146647","DOIUrl":"https://doi.org/10.1109/NER.2015.7146647","url":null,"abstract":"Computing the average input stimulus preceding a spike, the spike-triggered average (STA), has been a powerful tool for discovering a neuron's `preferred' stimulus feature that enables efficient encoding of sensory information. Recent work in the squid giant axon has shown that STA waveforms can be remarkably similar to the energetically optimal stimulus waveforms for eliciting a spike. In the present study, we show using the Hodgkin-Huxley model that the STA can deviate from the global optimal solution if there is averaging of multiple solutions across different time scales and of multiple modes of spike induction. These findings inform attempts to develop model-free stochastic algorithms for finding energy-optimal stimuli, which is relevant to the efficient delivery of exogenous therapeutic stimuli in neurological diseases.","PeriodicalId":137451,"journal":{"name":"2015 7th International IEEE/EMBS Conference on Neural Engineering (NER)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130281363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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