1
|
Rusinova A, Volodina M, Ossadtchi A. Short-term meditation training alters brain activity and sympathetic responses at rest, but not during meditation. Sci Rep 2024; 14:11138. [PMID: 38750127 PMCID: PMC11096169 DOI: 10.1038/s41598-024-60932-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/29/2024] [Indexed: 05/18/2024] Open
Abstract
Although more people are engaging in meditation practices that require specialized training, few studies address the issues associated with nervous activity pattern changes brought about by such training. For beginners, it remains unclear how much practice is needed before objective physiological changes can be detected, whether or not they are similar across the novices and what are the optimal strategies to track these changes. To clarify these questions we recruited individuals with no prior meditation experience. The experimental group underwent an eight-week Taoist meditation course administered by a professional, while the control group listened to audiobooks. Both groups participated in audio-guided, 34-min long meditation sessions before and after the 8-week long intervention. Their EEG, photoplethysmogram, respiration, and skin conductance were recorded during the mediation and resting state periods. Compared to the control group, the experimental group exhibited band-specific topically organized changes of the resting state brain activity and heart rate variability associated with sympathetic system activation. Importantly, no significant changes were found during the meditation process prior and post the 8-week training in either of the groups. The absence of notable changes in CNS and ANS activity indicators during meditation sessions, for both the experimental and control groups, casts doubt on the effectiveness of wearable biofeedback devices in meditation practice. This finding redirects focus to the importance of monitoring resting state activity to evaluate progress in beginner meditators. Also, 16 h of training is not enough for forming individual objectively different strategies manifested during the meditation sessions. Our results contributed to the development of tools to objectively monitor the progress in novice meditators and the choice of the relevant monitoring strategies. According to our findings, in order to track early changes brought about by the meditation practice it is preferable to monitor brain activity outside the actual meditation sessions.
Collapse
Affiliation(s)
- Anna Rusinova
- Center for Bioelectric Interfaces, HSE University, Moscow, Russia, 101000
| | - Maria Volodina
- Center for Bioelectric Interfaces, HSE University, Moscow, Russia, 101000.
- Laboratory of Medical Neurointerfaces and Artificial Intellect, Federal Center of Brain Research and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russia, 117513.
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, HSE University, Moscow, Russia, 101000
- Artificial Intelligence Research Institute, AIRI, Moscow, Russia
- LLC "Life Improvement by Future Technologies Center", Moscow, Russia
| |
Collapse
|
2
|
Altukhov D, Kleeva D, Ossadtchi A. PSIICOS projection optimality for EEG and MEG based functional coupling detection. Neuroimage 2023; 280:120333. [PMID: 37619795 DOI: 10.1016/j.neuroimage.2023.120333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 07/12/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
Functional connectivity is crucial for cognitive processes in the healthy brain and serves as a marker for a range of neuropathological conditions. Non-invasive exploration of functional coupling using temporally resolved techniques such as MEG allows for a unique opportunity of exploring this fundamental brain mechanism. The indirect nature of MEG measurements complicates the estimation of functional coupling due to the volume conduction and spatial leakage effects. In the previous work (Ossadtchi et al., 2018), we introduced PSIICOS, a method that for the first time allowed us to suppress the volume conduction effect and yet retain information about functional networks whose nodes are coupled with close to zero or zero mutual phase lag. In this paper, we demonstrate analytically that the PSIICOS projection is optimal in achieving a controllable trade-off between suppressing mutual spatial leakage and retaining information about zero- or close to zero-phase coupled networks. We also derive an alternative solution using the regularization-based inverse of the mutual spatial leakage matrix and show its equivalence to the original PSIICOS. We then discuss how PSIICOS solution to the functional connectivity estimation problem can be incorporated into the conventional source estimation framework. Instead of sources, the unknowns are the elementary dyadic networks and their activation time series are formalized by the corresponding source-space cross-spectral coefficients. This view on connectivity estimation as a regression problem opens up new opportunities for formulating a set of principled estimators based on the rich intuition accumulated in the neuroimaging community.
Collapse
Affiliation(s)
- Dmitrii Altukhov
- AIRI, Artificial Intelligence Research Institute, Moscow, Russia
| | - Daria Kleeva
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia; AIRI, Artificial Intelligence Research Institute, Moscow, Russia; LLC "Life Improvement by Future Technologies Center", Moscow, Russia.
| |
Collapse
|
3
|
Semenkov I, Fedosov N, Makarov I, Ossadtchi A. Real-time low latency estimation of brain rhythms with deep neural networks. J Neural Eng 2023; 20:056008. [PMID: 37683653 DOI: 10.1088/1741-2552/acf7f3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 09/08/2023] [Indexed: 09/10/2023]
Abstract
Objective.Neurofeedback and brain-computer interfacing technology open the exciting opportunity for establishing interactive closed-loop real-time communication with the human brain. This requires interpreting brain's rhythmic activity and generating timely feedback to the brain. Lower delay between neuronal events and the appropriate feedback increases the efficacy of such interaction. Novel more efficient approaches capable of tracking brain rhythm's phase and envelope are needed for scenarios that entail instantaneous interaction with the brain circuits.Approach.Isolating narrow-band signals incurs fundamental delays. To some extent they can be compensated using forecasting models. Given the high quality of modern time series forecasting neural networks we explored their utility for low-latency extraction of brain rhythm parameters. We tested five neural networks with conceptually distinct architectures in forecasting synthetic EEG rhythms. The strongest architecture was then trained to simultaneously filter and forecast EEG data. We compared it against the state-of-the-art techniques using synthetic and real data from 25 subjects.Main results.The temporal convolutional network (TCN) remained the strongest forecasting model that achieved in the majority of testing scenarios>90% rhythm's envelope correlation with<10 ms effective delay and<20∘circular standard deviation of phase estimates. It also remained stable enough to noise level perturbations. Trained to filter and predict the TCN outperformed the cFIR, the Kalman filter based state-space estimation technique and remained on par with the larger Conv-TasNet architecture.Significance.Here we have for the first time demonstrated the utility of the neural network approach for low-latency narrow-band filtering of brain activity signals. Our proposed approach coupled with efficient implementation enhances the effectiveness of brain-state dependent paradigms across various applications. Moreover, our framework for forecasting EEG signals holds promise for investigating the predictability of brain activity, providing valuable insights into the fundamental questions surrounding the functional organization and hierarchical information processing properties of the brain.
Collapse
Affiliation(s)
- Ilia Semenkov
- Artificial Intelligence Research Institute (AIRI), Moscow 105064, Russia
- HSE University, Moscow 109028, Russia
| | - Nikita Fedosov
- Artificial Intelligence Research Institute (AIRI), Moscow 105064, Russia
- HSE University, Moscow 109028, Russia
| | - Ilya Makarov
- Artificial Intelligence Research Institute (AIRI), Moscow 105064, Russia
| | - Alexei Ossadtchi
- Artificial Intelligence Research Institute (AIRI), Moscow 105064, Russia
- HSE University, Moscow 109028, Russia
- LLC 'Life Improvement by Future Technologies Center', Moscow, Russia
| |
Collapse
|
4
|
Petrosyan A, Voskoboinikov A, Sukhinin D, Makarova A, Skalnaya A, Arkhipova N, Sinkin M, Ossadtchi A. Speech decoding from a small set of spatially segregated minimally invasive intracranial EEG electrodes with a compact and interpretable neural network. J Neural Eng 2022; 19. [PMID: 36356309 DOI: 10.1088/1741-2552/aca1e1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 11/10/2022] [Indexed: 11/12/2022]
Abstract
Objective. Speech decoding, one of the most intriguing brain-computer interface applications, opens up plentiful opportunities from rehabilitation of patients to direct and seamless communication between human species. Typical solutions rely on invasive recordings with a large number of distributed electrodes implanted through craniotomy. Here we explored the possibility of creating speech prosthesis in a minimally invasive setting with a small number of spatially segregated intracranial electrodes.Approach. We collected one hour of data (from two sessions) in two patients implanted with invasive electrodes. We then used only the contacts that pertained to a single stereotactic electroencephalographic (sEEG) shaft or an electrocorticographic (ECoG) stripe to decode neural activity into 26 words and one silence class. We employed a compact convolutional network-based architecture whose spatial and temporal filter weights allow for a physiologically plausible interpretation.Mainresults. We achieved on average 55% accuracy using only six channels of data recorded with a single minimally invasive sEEG electrode in the first patient and 70% accuracy using only eight channels of data recorded for a single ECoG strip in the second patient in classifying 26+1 overtly pronounced words. Our compact architecture did not require the use of pre-engineered features, learned fast and resulted in a stable, interpretable and physiologically meaningful decision rule successfully operating over a contiguous dataset collected during a different time interval than that used for training. Spatial characteristics of the pivotal neuronal populations corroborate with active and passive speech mapping results and exhibit the inverse space-frequency relationship characteristic of neural activity. Compared to other architectures our compact solution performed on par or better than those recently featured in neural speech decoding literature.Significance. We showcase the possibility of building a speech prosthesis with a small number of electrodes and based on a compact feature engineering free decoder derived from a small amount of training data.
Collapse
Affiliation(s)
- Artur Petrosyan
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia
| | | | - Dmitrii Sukhinin
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia
| | - Anna Makarova
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia
| | | | | | - Mikhail Sinkin
- Moscow State University of Medicine and Dentistry, Scientific Research Institute of First Aid to them. N.V. Sklifosovsky, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia.,Artificial Intelligence Research Institute, AIRI, Moscow, Russia
| |
Collapse
|
5
|
Chirkov V, Kryuchkova A, Koptelova A, Stroganova T, Kuznetsova A, Kleeva D, Ossadtchi A, Fedele T. Data-driven approach for the delineation of the irritative zone in epilepsy in MEG. PLoS One 2022; 17:e0275063. [PMID: 36282803 PMCID: PMC9595543 DOI: 10.1371/journal.pone.0275063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 09/09/2022] [Indexed: 11/06/2022] Open
Abstract
The reliable identification of the irritative zone (IZ) is a prerequisite for the correct clinical evaluation of medically refractory patients affected by epilepsy. Given the complexity of MEG data, visual analysis of epileptiform neurophysiological activity is highly time consuming and might leave clinically relevant information undetected. We recorded and analyzed the interictal activity from seven patients affected by epilepsy (Vectorview Neuromag), who successfully underwent epilepsy surgery (Engel > = II). We visually marked and localized characteristic epileptiform activity (VIS). We implemented a two-stage pipeline for the detection of interictal spikes and the delineation of the IZ. First, we detected candidate events from peaky ICA components, and then clustered events around spatio-temporal patterns identified by convolutional sparse coding. We used the average of clustered events to create IZ maps computed at the amplitude peak (PEAK), and at the 50% of the peak ascending slope (SLOPE). We validated our approach by computing the distance of the estimated IZ (VIS, SLOPE and PEAK) from the border of the surgically resected area (RA). We identified 25 spatiotemporal patterns mimicking the underlying interictal activity (3.6 clusters/patient). Each cluster was populated on average by 22.1 [15.0–31.0] spikes. The predicted IZ maps had an average distance from the resection margin of 8.4 ± 9.3 mm for visual analysis, 12.0 ± 16.5 mm for SLOPE and 22.7 ±. 16.4 mm for PEAK. The consideration of the source spread at the ascending slope provided an IZ closer to RA and resembled the analysis of an expert observer. We validated here the performance of a data-driven approach for the automated detection of interictal spikes and delineation of the IZ. This computational framework provides the basis for reproducible and bias-free analysis of MEG recordings in epilepsy.
Collapse
Affiliation(s)
- Valerii Chirkov
- Berlin School of Mind and Brain, Humboldt University, Berlin, Germany
| | - Anna Kryuchkova
- Center for Neurocognitive Research, MEG Center, MSUPE, Moscow, Russian Federation
| | - Alexandra Koptelova
- Center for Neurocognitive Research, MEG Center, MSUPE, Moscow, Russian Federation
| | - Tatiana Stroganova
- Center for Neurocognitive Research, MEG Center, MSUPE, Moscow, Russian Federation
| | - Alexandra Kuznetsova
- Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russian Federation
| | - Daria Kleeva
- Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russian Federation
| | - Alexei Ossadtchi
- Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russian Federation
| | - Tommaso Fedele
- Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russian Federation
- * E-mail:
| |
Collapse
|
6
|
Kleeva D, Soghoyan G, Komoltsev I, Sinkin M, Ossadtchi A. Fast parametric curve matching (FPCM) for automatic spike detection. J Neural Eng 2022; 19. [PMID: 35439749 DOI: 10.1088/1741-2552/ac682a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 04/18/2022] [Indexed: 11/12/2022]
Abstract
Epilepsy is a widely spread neurological disease, whose treatment often requires resection of the pathological cortical tissue. Interictal spike analysis observed in the non-invasively collected EEG or MEG data offers a way to localize epileptogenic cortical structures for surgery planning purposes. While a plethora of automatic spike detection techniques have been developed each with its own assumptions and limitations, non of them is ideal and the best results are achieved when the output of several automatic spike detectors are combined. This is especially true in the low signal-to-noise ratio conditions. To this end we propose a novel biomimetic approach for automatic spike detection based on a constrained mixed spline machinery that we dub as fast parametric curve matching (FPCM). Using the peak-wave shape parametrization, the constrained parametric morphological model is constructed and convolved with the observed multichannel data to very efficiently determine mixed spline parameters corresponding to each time-point in the dataset. Then the logical predicates that directly map to the expected interictal event morphology allow us to accomplish the spike detection task. The results of simulations mimicking typical low SNR scenario show the robustness and high ROC AUC values of the FPCM method as compared to the spike detection performed by the means of more conventional approaches such as wavelet decomposition, template matching or simple amplitude thresholding. Applied to the real MEG and EEG data from the human patients and to ECoG data from the rat, the FPCM technique demonstrates reliable detection of the interictal events and localization of epileptogenic zones concordant with independent conclusions made by the epileptologist. Since the FPCM is computationally light, tolerant to high amplitude artifacts and flexible to accommodate verbalized descriptions of the arbitrary target morphology, it may complement the existing arsenal of means for analysis of noisy interictal datasets.
Collapse
Affiliation(s)
- Daria Kleeva
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia
| | - Gurgen Soghoyan
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia
| | - Ilia Komoltsev
- Laboratory of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.,Moscow Research and Clinical Center for Neuropsychiatry of the Healthcare Department of Moscow, Moscow, Russia
| | - Mikhail Sinkin
- A I Evdokimov Moscow State University of Medicical Dentistry, Moscow, Russia.,N V Sklifosovsky Research Institute of Emergency Medicine, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, Russia.,AIRI, Artificial Intelligence Research Institute, Moscow, Russia
| |
Collapse
|
7
|
Volodina M, Smetanin N, Lebedev M, Ossadtchi A. Cortical and autonomic responses during staged Taoist meditation: Two distinct meditation strategies. PLoS One 2021; 16:e0260626. [PMID: 34855823 PMCID: PMC8638869 DOI: 10.1371/journal.pone.0260626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/12/2021] [Indexed: 11/28/2022] Open
Abstract
Meditation is a consciousness state associated with specific physiological and neural correlates. Numerous investigations of these correlates reported controversial results which prevented a consistent depiction of the underlying neurophysiological processes. Here we investigated the dynamics of multiple neurophysiological indicators during a staged meditation session. We measured the physiological changes at rest and during the guided Taoist meditation in experienced meditators and naive subjects. We recorded EEG, respiration, galvanic skin response, and photoplethysmography. All subjects followed the same instructions split into 16 stages. In the experienced meditators group we identified two subgroups with different physiological markers dynamics. One subgroup showed several signs of general relaxation evident from the changes in heart rate variability, respiratory rate, and EEG rhythmic activity. The other subgroup exhibited mind concentration patterns primarily noticeable in the EEG recordings while no autonomic responses occurred. The duration and type of previous meditation experience or any baseline indicators we measured did not explain the segregation of the meditators into these two groups. These results suggest that two distinct meditation strategies could be used by experienced meditators, which partly explains the inconsistent results reported in the earlier studies evaluating meditation effects. Our findings are also relevant to the development of the high-end biofeedback systems.
Collapse
Affiliation(s)
- Maria Volodina
- Center for Bioelectric Interfaces, HSE University, Moscow, Russia
| | - Nikolai Smetanin
- Center for Bioelectric Interfaces, HSE University, Moscow, Russia
| | - Mikhail Lebedev
- Center for Bioelectric Interfaces, HSE University, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, HSE University, Moscow, Russia
- Artificial intelligence Research Institute, Moscow, Russia
| |
Collapse
|
8
|
Ossadtchi A, Pazgalev A, Petrenko M, Vershovskii A. Promising Versions of Non-Zero Magnetic Field Optical Sensors for Magnetoencephalography. Int J Psychophysiol 2021. [DOI: 10.1016/j.ijpsycho.2021.07.352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
9
|
Fedosov N, Ossadtchi A. Propagating Dynamics of Interictal Spikes Reconstructed From MEG Recordings. Int J Psychophysiol 2021. [DOI: 10.1016/j.ijpsycho.2021.07.518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
10
|
Koshev N, Butorina A, Skidchenko E, Kuzmichev A, Ossadtchi A, Ostras M, Fedorov M, Vetoshko P. Evolution of MEG: A first MEG-feasible fluxgate magnetometer. Hum Brain Mapp 2021; 42:4844-4856. [PMID: 34327772 PMCID: PMC8449095 DOI: 10.1002/hbm.25582] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/24/2021] [Accepted: 06/10/2021] [Indexed: 11/15/2022] Open
Abstract
In the current article, we present the first solid‐state sensor feasible for magnetoencephalography (MEG) that works at room temperature. The sensor is a fluxgate magnetometer based on yttrium‐iron garnet films (YIGM). In this feasibility study, we prove the concept of usage of the YIGM in terms of MEG by registering a simple brain induced field—the human alpha rhythm. All the experiments and results are validated with usage of another kind of high‐sensitive magnetometers—optically pumped magnetometer, which currently appears to be well‐established in terms of MEG.
Collapse
Affiliation(s)
- Nikolay Koshev
- Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Anna Butorina
- Skolkovo Institute of Science and Technology, Moscow, Russia
| | | | | | | | - Maxim Ostras
- M-Granat, Russian Quantum Center, Moscow, Russia
| | - Maxim Fedorov
- Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Petr Vetoshko
- M-Granat, Russian Quantum Center, Moscow, Russia.,Kotelnikov Institute of Radioengineering and Electronics of RAS, Moscow, Russia
| |
Collapse
|
11
|
Gorin A, Klucharev V, Ossadtchi A, Zubarev I, Moiseeva V, Shestakova A. MEG signatures of long-term effects of agreement and disagreement with the majority. Sci Rep 2021; 11:3297. [PMID: 33558577 PMCID: PMC7870674 DOI: 10.1038/s41598-021-82670-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 01/15/2021] [Indexed: 01/10/2023] Open
Abstract
People often change their beliefs by succumbing to an opinion of others. Such changes are often referred to as effects of social influence. While some previous studies have focused on the reinforcement learning mechanisms of social influence or on its internalization, others have reported evidence of changes in sensory processing evoked by social influence of peer groups. In this study, we used magnetoencephalographic (MEG) source imaging to further investigate the long-term effects of agreement and disagreement with the peer group. The study was composed of two sessions. During the first session, participants rated the trustworthiness of faces and subsequently learned group rating of each face. In the first session, a neural marker of an immediate mismatch between individual and group opinions was found in the posterior cingulate cortex, an area involved in conflict-monitoring and reinforcement learning. To identify the neural correlates of the long-lasting effect of the group opinion, we analysed MEG activity while participants rated faces during the second session. We found MEG traces of past disagreement or agreement with the peers at the parietal cortices 230 ms after the face onset. The neural activity of the superior parietal lobule, intraparietal sulcus, and precuneus was significantly stronger when the participant’s rating had previously differed from the ratings of the peers. The early MEG correlates of disagreement with the majority were followed by activity in the orbitofrontal cortex 320 ms after the face onset. Altogether, the results reveal the temporal dynamics of the neural mechanism of long-term effects of disagreement with the peer group: early signatures of modified face processing were followed by later markers of long-term social influence on the valuation process at the ventromedial prefrontal cortex.
Collapse
Affiliation(s)
- A Gorin
- International Laboratory of Social Neurobiology, Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia.
| | - V Klucharev
- International Laboratory of Social Neurobiology, Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
| | - A Ossadtchi
- Centre for Bioelectric Interfaces, Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
| | - I Zubarev
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - V Moiseeva
- International Laboratory of Social Neurobiology, Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
| | - A Shestakova
- International Laboratory of Social Neurobiology, Institute of Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
| |
Collapse
|
12
|
Petrosyan A, Sinkin M, Lebedev MA, Ossadtchi A. Decoding and interpreting cortical signals with a compact convolutional neural network. J Neural Eng 2021; 18. [PMID: 33524962 DOI: 10.1088/1741-2552/abe20e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/01/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Brain-computer interfaces (BCIs) decode information from neural activity and send it to external devices. The use of Deep Learning approaches for decoding allows for automatic feature engineering within the specific decoding task. Physiologically plausible interpretation of the network parameters ensures the robustness of the learned decision rules and opens the exciting opportunity for automatic knowledge discovery. APPROACH We describe a compact convolutional network-based architecture for adaptive decoding of electrocorticographic (ECoG) data into finger kinematics. We also propose a novel theoretically justified approach to interpreting the spatial and temporal weights in the architectures that combine adaptation in both space and time. The obtained spatial and frequency patterns characterizing the neuronal populations pivotal to the specific decoding task can then be interpreted by fitting appropriate spatial and dynamical models. MAIN RESULTS We first tested our solution using realistic Monte-Carlo simulations. Then, when applied to the ECoG data from Berlin BCI competition IV dataset, our architecture performed comparably to the competition winners without requiring explicit feature engineering. Using the proposed approach to the network weights interpretation we could unravel the spatial and the spectral patterns of the neuronal processes underlying the successful decoding of finger kinematics from an ECoG dataset. Finally we have also applied the entire pipeline to the analysis of a 32-channel EEG motor-imagery dataset and observed physiologically plausible patterns specific to the task. SIGNIFICANCE We described a compact and interpretable CNN architecture derived from the basic principles and encompassing the knowledge in the field of neural electrophysiology. For the first time in the context of such multibranch architectures with factorized spatial and temporal processing we presented theoretically justified weights interpretation rules. We verified our recipes using simulations and real data and demonstrated that the proposed solution offers a good decoder and a tool for investigating motor control neural mechanisms.
Collapse
Affiliation(s)
- Artur Petrosyan
- Center for Bioelectric Interfaces, Higher School of Economics, Krivokolennyi per., 3, Moscow, Russia, 10100, RUSSIAN FEDERATION
| | - Mikhail Sinkin
- A I Yevdokimov Moscow State University of Medicine and Dentistry of the Ministry of Healthcare of the Russian Federation Faculty of Dentistry, Delegatskaya St., 20, p. 1, Moskva, Moskva, 127473, RUSSIAN FEDERATION
| | - M A Lebedev
- Neurobiology, Duke University, Hudson Hall 136, Durham, NC 27708-0281, USA, Durham, 27517, UNITED STATES
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, Higher School of Economics, Krivokolennyi per., 3, Moscow, Russia, 101000, RUSSIAN FEDERATION
| |
Collapse
|
13
|
Kuznetsova A, Nurislamova Y, Ossadtchi A. Modified covariance beamformer for solving MEG inverse problem in the environment with correlated sources. Neuroimage 2020; 228:117677. [PMID: 33385549 DOI: 10.1016/j.neuroimage.2020.117677] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 11/10/2020] [Accepted: 12/17/2020] [Indexed: 02/02/2023] Open
Abstract
Magnetoencephalography (MEG) is a neuroimaging method ideally suited for non-invasive studies of brain dynamics. MEG's spatial resolution critically depends on the approach used to solve the ill-posed inverse problem in order to transform sensor signals into cortical activation maps. Over recent years non-globally optimized solutions based on the use of adaptive beamformers (BF) gained popularity. When operating in the environment with a small number of uncorrelated sources the BFs perform optimally and yield high spatial resolution. However, the BFs are known to fail when dealing with correlated sources acting like poorly tuned spatial filters with low signal-to-noise ratio (SNR) of the output timeseries and often meaningless cortical maps of power distribution. This fact poses a serious limitation on the broader use of this promising technique especially since fundamental mechanisms of brain functioning, its inherent symmetry and task-based experimental paradigms result into a great deal of correlation in the activity of cortical sources. To cope with this problem, we developed a novel data covariance modification approach that allows for building beamformers that maintain high spatial resolution when operating in the environments with correlated sources. At the core of our method is a projection operation applied to the vectorized sensor-space covariance matrix. This projection does not remove the activity of the correlated sources from the sensor-space covariance matrix but rather selectively handles their contributions to the covariance matrix and creates a sufficiently accurate approximation of an ideal data covariance that could hypothetically be observed should these sources be uncorrelated. Since the projection operation is reciprocal to the PSIICOS method developed by us earlier (Ossadtchi et al., 2018) we refer to the family of algorithms presented here as ReciPSIICOS. We assess the performance of the novel approach using realistically simulated MEG data and show its superior performance in comparison to the classical BF approaches and well established MNE as a method immune to source synchrony by design. We have also applied our approach to the MEG datasets from the two experiments involving two different auditory tasks. The analysis of experimental MEG datasets showed that beamformers from ReciPSIICOS family, but not the classical BF, discovered the expected bilateral focal sources in the primary auditory cortex and detected motor cortex activity associated with the audio-motor task. In most cases MNE managed well but as expected produced more spatially diffuse source distributions. Notably, ReciPSIICOS beamformers yielded cortical activity estimates with SNR several times higher than that obtained with the classical BF, which may indirectly indicate the severeness of the signal cancellation problem when applying classical beamformers to MEG signals generated by synchronous sources.
Collapse
Affiliation(s)
- Aleksandra Kuznetsova
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow 101000, Russia.
| | - Yulia Nurislamova
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow 101000, Russia.
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow 101000, Russia.
| |
Collapse
|
14
|
Kirasirova L, Bulanov V, Ossadtchi A, Kolsanov A, Pyatin V, Lebedev M. A P300 Brain-Computer Interface With a Reduced Visual Field. Front Neurosci 2020; 14:604629. [PMID: 33343290 PMCID: PMC7744588 DOI: 10.3389/fnins.2020.604629] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/09/2020] [Indexed: 11/13/2022] Open
Abstract
A P300 brain-computer interface (BCI) is a paradigm, where text characters are decoded from event-related potentials (ERPs). In a popular implementation, called P300 speller, a subject looks at a display where characters are flashing and selects one character by attending to it. The selection is recognized as the item with the strongest ERP. The speller performs well when cortical responses to target and non-target stimuli are sufficiently different. Although many strategies have been proposed for improving the BCI spelling, a relatively simple one received insufficient attention in the literature: reduction of the visual field to diminish the contribution from non-target stimuli. Previously, this idea was implemented in a single-stimulus switch that issued an urgent command like stopping a robot. To tackle this approach further, we ran a pilot experiment where ten subjects operated a traditional P300 speller or wore a binocular aperture that confined their sight to the central visual field. As intended, visual field restriction resulted in a replacement of non-target ERPs with EEG rhythms asynchronous to stimulus periodicity. Changes in target ERPs were found in half of the subjects and were individually variable. While classification accuracy was slightly better for the aperture condition (84.3 ± 2.9%, mean ± standard error) than the no-aperture condition (81.0 ± 2.6%), this difference was not statistically significant for the entire sample of subjects (N = 10). For both the aperture and no-aperture conditions, classification accuracy improved over 4 days of training, more so for the aperture condition (from 72.0 ± 6.3% to 87.0 ± 3.9% and from 72.0 ± 5.6% to 97.0 ± 2.2% for the no-aperture and aperture conditions, respectively). Although in this study BCI performance was not substantially altered, we suggest that with further refinement this approach could speed up BCI operations and reduce user fatigue. Additionally, instead of wearing an aperture, non-targets could be removed algorithmically or with a hybrid interface that utilizes an eye tracker. We further discuss how a P300 speller could be improved by taking advantage of the different physiological properties of the central and peripheral vision. Finally, we suggest that the proposed experimental approach could be used in basic research on the mechanisms of visual processing.
Collapse
Affiliation(s)
| | - Vladimir Bulanov
- Laboratory of Mathematical Processing of Biological Information, IT Universe Ltd, Samara, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
| | | | | | - Mikhail Lebedev
- Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
- Department of Information and Internet Technologies of Digital Health Institute, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
- Center For Neurobiology and Brain Restoration, Skolkovo Institute of Science and Technology, Moscow, Russia
| |
Collapse
|
15
|
Belinskaya A, Smetanin N, Lebedev MA, Ossadtchi A. Short-delay neurofeedback facilitates training of the parietal alpha rhythm. J Neural Eng 2020; 17. [PMID: 33166941 DOI: 10.1088/1741-2552/abc8d7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/09/2020] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Feedback latency was shown to be a critical parameter in a range of applications that imply learning. The therapeutic effects of neurofeedback (NFB) remain controversial. We hypothesized that often encountered unreliable results of NFB intervention could be associated with large feedback latency values that are often uncontrolled and may preclude the efficient learning. APPROACH We engaged our subjects into a parietal alpha power unpregulating paradigm faciliated by visual neurofeedback based on the invidually extracted envelope of the alpha-rhythm at P4 electrode. NFB was displayed either as soon as EEG envelope was processed, or with an extra 250 or 500-ms delay. The feedback training consisted of 15 two-minute long blocks interleaved with 15s pauses. We have also recorded two minute long baselines immediately before and after the training. MAIN RESULTS The time course of NFB-induced changes in the alpha rhythm power clearly depended on NFB latency, as shown with the adaptive Neyman test. NFB had a strong effect on the alpha-spindle incidence rate, but not on their duration or amplitude. The sustained changes in alpha activity measured after the completion of NFB training were negatively correlated to latency, with the maximum change for the shortest tested latency and no change for the longest. SIGNIFICANCE Here we for the first time show that visual NFB of parietal electroencephalographic (EEG) alpha-activity is efficient only when delivered to human subjects at short latency, which guarantees that NFB arrives when an alpha spindle is still ongoing. Such a considerable effect of NFB latency on the alpha-activity temporal structure could explain some of the previous inconsistent results, where latency was neither controlled nor documented. Clinical practitioners and manufacturers of NFB equipment should add latency to their specifications while enabling latency monitoring and supporting short-latency operations.
Collapse
Affiliation(s)
- Anastasia Belinskaya
- Centre for Bioelectric Interfaces, National Research University Higher School of Economics, Moskva, Moskva, RUSSIAN FEDERATION
| | - Nikolai Smetanin
- Centre for Bioelectric Interfaces, National Research University Higher School of Economics, Moskva, Moskva, RUSSIAN FEDERATION
| | - M A Lebedev
- Center for Bioelectric Interfaces, National Research University Higher School of Economics, Moskva, Moskva, RUSSIAN FEDERATION
| | - Alexei Ossadtchi
- Center for bioelectirc interfaces, National Research University Higher School of Economics, Moskva, Moskva, RUSSIAN FEDERATION
| |
Collapse
|
16
|
Abstract
OBJECTIVE The rapidly developing paradigm of closed-loop neuroscience has extensively employed brain rhythms as the signal forming real-time neurofeedback, triggering brain stimulation, or governing stimulus selection. However, the efficacy of brain rhythm contingent paradigms suffers from significant delays related to the process of extraction of oscillatory parameters from broad-band neural signals with conventional methods. To this end, real-time algorithms are needed that would shorten the delay while maintaining an acceptable speed-accuracy trade-off. APPROACH Here we evaluated a family of techniques based on the application of the least-squares complex-valued filter (LSCF) design to real-time quantification of brain rhythms. These techniques allow for explicit optimization of the speed-accuracy trade-off when quantifying oscillatory patterns. We used EEG data collected from 10 human participants to systematically compare LSCF approach to the other commonly used algorithms. Each method being evaluated was optimized by scanning through the grid of its hyperparameters using independent data samples. MAIN RESULTS When applied to the task of estimating oscillatory envelope and phase, the LSCF techniques outperformed in speed and accuracy both conventional Fourier transform and rectification based methods as well as more advanced techniques such as those that exploit autoregressive extrapolation of narrow-band filtered signals. When operating at zero latency, the weighted LSCF approach yielded 75% accuracy when detecting alpha-activity episodes, as defined by the amplitude crossing of the 95th-percentile threshold. SIGNIFICANCE The LSCF approaches are easily applicable to low-delay quantification of brain rhythms. As such, these methods are useful in a variety of neurofeedback, brain-computer-interface and other experimental paradigms that require rapid monitoring of brain rhythms.
Collapse
Affiliation(s)
- Nikolai Smetanin
- Center for Bioelectric Interfaces, Higher School of Economics, Moscow, 101000, Russia
| | | | | | | |
Collapse
|
17
|
Ros T, Enriquez-Geppert S, Zotev V, Young KD, Wood G, Whitfield-Gabrieli S, Wan F, Vuilleumier P, Vialatte F, Van De Ville D, Todder D, Surmeli T, Sulzer JS, Strehl U, Sterman MB, Steiner NJ, Sorger B, Soekadar SR, Sitaram R, Sherlin LH, Schönenberg M, Scharnowski F, Schabus M, Rubia K, Rosa A, Reiner M, Pineda JA, Paret C, Ossadtchi A, Nicholson AA, Nan W, Minguez J, Micoulaud-Franchi JA, Mehler DMA, Lührs M, Lubar J, Lotte F, Linden DEJ, Lewis-Peacock JA, Lebedev MA, Lanius RA, Kübler A, Kranczioch C, Koush Y, Konicar L, Kohl SH, Kober SE, Klados MA, Jeunet C, Janssen TWP, Huster RJ, Hoedlmoser K, Hirshberg LM, Heunis S, Hendler T, Hampson M, Guggisberg AG, Guggenberger R, Gruzelier JH, Göbel RW, Gninenko N, Gharabaghi A, Frewen P, Fovet T, Fernández T, Escolano C, Ehlis AC, Drechsler R, Christopher deCharms R, Debener S, De Ridder D, Davelaar EJ, Congedo M, Cavazza M, Breteler MHM, Brandeis D, Bodurka J, Birbaumer N, Bazanova OM, Barth B, Bamidis PD, Auer T, Arns M, Thibault RT. Consensus on the reporting and experimental design of clinical and cognitive-behavioural neurofeedback studies (CRED-nf checklist). Brain 2020; 143:1674-1685. [PMID: 32176800 PMCID: PMC7296848 DOI: 10.1093/brain/awaa009] [Citation(s) in RCA: 147] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 10/10/2019] [Accepted: 10/28/2020] [Indexed: 02/02/2023] Open
Abstract
Neurofeedback has begun to attract the attention and scrutiny of the scientific and medical mainstream. Here, neurofeedback researchers present a consensus-derived checklist that aims to improve the reporting and experimental design standards in the field.
Collapse
Affiliation(s)
- Tomas Ros
- Departments of Neuroscience and Psychiatry, University of Geneva; Campus Biotech, Geneva, Switzerland
| | - Stefanie Enriquez-Geppert
- Department of Clinical Neuropsychology, University of Groningen, Groningen, The Netherlands
- Department of Biomedical Sciences of Cells & Systems, University Medical Center Groningen, Groningen, The Netherlands
| | - Vadim Zotev
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA
| | - Kymberly D Young
- University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Guilherme Wood
- Institute of Psychology, University of Graz, Graz, Austria
| | - Susan Whitfield-Gabrieli
- Massachusetts Institute of Technology, Cambridge, MA, USA
- Northeastern University, Boston, MA, USA
| | - Feng Wan
- Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
| | | | | | - Dimitri Van De Ville
- Institute of Bioengineering, Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne (EPFL); Campus Biotech, Geneva, Switzerland
| | - Doron Todder
- Faculty of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Beer-Sheva Mental Health Center, Israel Ministry of Health, Beer-Sheva, Israel
| | - Tanju Surmeli
- Living Health Center for Research and Education, Istanbul, Turkey
| | - James S Sulzer
- Department of Mechanical Engineering, University of Texas at Austin, Austin, TX, USA
| | - Ute Strehl
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Maurice Barry Sterman
- Neurobiology and Biobehavioral Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Naomi J Steiner
- Boston University School of Medicine, Department of Pediatrics, Boston, MA, USA
| | - Bettina Sorger
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Surjo R Soekadar
- Clinical Neurotechnology Laboratory, Neuroscience Research Center (NWFZ), Department of Psychiatry and Psychotherapy (CCM), Charité - University Medicine Berlin, Berlin, Germany
| | - Ranganatha Sitaram
- Institute of Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Macul, Santiago, Chile
| | | | | | - Frank Scharnowski
- Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Vienna, Austria
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zürich, Zürich, Switzerland
| | - Manuel Schabus
- University of Salzburg, Centre for Cognitive Neuroscience and Department of Psychology, Salzburg, Austria
| | - Katya Rubia
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | | | - Miriam Reiner
- Technion, Israel Institute of Technology, Haifa, Israel
| | - Jaime A Pineda
- Cognitive Science Department, University of California, San Diego, CA, USA
| | - Christian Paret
- Department of Psychosomatic Medicine and Psychotherapy, Central Institute of Mental Health Mannheim, Medical Faculty Mannheim/Heidelberg University, Germany
| | - Alexei Ossadtchi
- National Research University Higher School of Economics, Moscow, Russia
| | - Andrew A Nicholson
- Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Vienna, Austria
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zürich, Zürich, Switzerland
| | - Wenya Nan
- Department of Psychology, Shanghai Normal University, Shanghai, China
| | | | | | - David M A Mehler
- Department of Psychiatry, University of Münster, Münster, Germany
| | - Michael Lührs
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Joel Lubar
- Department of Psychology, University of Tennessee, Knoxville, USA
| | - Fabien Lotte
- Inria Bordeaux Sud-Ouest/LaBRI University of Bordeaux - CNRS-Bordeaux INP, Bordeaux, France
| | - David E J Linden
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | | | - Mikhail A Lebedev
- Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
- Department of Information and Internet Technologies of Digital Health Institute; I.M. Sechenov First Moscow State Medical University, Moscow, Russia
- Duke Center for Neuroengineering, Duke University, Durham, NC, USA
| | - Ruth A Lanius
- Department of Psychiatry, Western University, London, Ontario, Canada
| | - Andrea Kübler
- Department of Psychology I, Psychological Intervention, Behavior Analysis and Regulation of Behavior, University of Würzburg
| | - Cornelia Kranczioch
- Neuropsychology Lab, Department of Psychology, University of Oldenburg, Oldenberg, Germany
| | - Yury Koush
- Magnetic Resonance Research Center (MRRC), Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Lilian Konicar
- Medical University of Vienna, Department of Child and Adolescent Psychiatry, Vienna, Austria
| | - Simon H Kohl
- JARA-Institute Molecular neuroscience and neuroimaging (INM-11), Jülich Research Centre, Jülich, Germany
| | | | - Manousos A Klados
- Department of Psychology, The University of Sheffield International Faculty, City College, Thessaloniki, Greece
| | - Camille Jeunet
- CLLE Lab, CNRS, Université Toulouse Jean Jaurès, Toulouse, France
| | - T W P Janssen
- Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Rene J Huster
- Multimodal imaging and Cognitive Control Lab, Department of Psychology, University of Olso, Norway
| | - Kerstin Hoedlmoser
- University of Salzburg, Centre for Cognitive Neuroscience and Department of Psychology, Salzburg, Austria
| | | | - Stephan Heunis
- Electrical Engineering Department, Eindhoven University of Technology, The Netherlands
| | - Talma Hendler
- Sagol Brain Institute, Wohl Institute for Advanced Imaging, Sourasky Medical Center, Tel Aviv, Israel
| | - Michelle Hampson
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Adrian G Guggisberg
- Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital Geneva, Geneva, Switzerland
| | - Robert Guggenberger
- Division of Functional and Restorative Neurosurgery, University of Tübingen, Tübingen, Germany
| | - John H Gruzelier
- Department of Psychology, Goldsmiths, University of London, London, UK
| | - Rainer W Göbel
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Nicolas Gninenko
- Institute of Bioengineering, Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne (EPFL); Campus Biotech, Geneva, Switzerland
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Paul Frewen
- Department of Psychiatry, Western University, London, Ontario, Canada
| | - Thomas Fovet
- Univ. Lille, INSERM U1172, CHU LILLE, Centre Lille Neuroscience & Cognition, Pôle de Psychiatrie, F-59000, Lille, France
| | - Thalía Fernández
- UNAM Institute of Neurobiology, National Autonomous University of Mexico, Juriquilla, Mexico
| | | | - Ann-Christine Ehlis
- Psychophysiology and Optical Imaging, Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Renate Drechsler
- Department of Child and Adolescent, Psychiatry and Psychotherapy, Psychiatric Hospital, University of Zürich, Zürich, Switzerland
| | | | - Stefan Debener
- Neuropsychology Lab, Department of Psychology, University of Oldenburg, Oldenberg, Germany
| | - Dirk De Ridder
- Department of Surgery, Section of Neurosurgery, University of Otago, Dunedin, New Zealand
| | - Eddy J Davelaar
- Department of Psychological Sciences Birkbeck, University of London, Bloomsbury, London, UK
| | - Marco Congedo
- GIPSA-lab, CNRS, University Grenoble Alpes, Grenoble-INP, Grenoble, France
| | - Marc Cavazza
- School of Computing and Mathematical Sciences, University of Greenwich, London, UK
| | - Marinus H M Breteler
- Radboud University Nijmegen, Department of Clinical Psychology, Nijmegen, The Netherlands
| | - Daniel Brandeis
- Department of Child and Adolescent, Psychiatry and Psychotherapy, Psychiatric Hospital, University of Zürich, Zürich, Switzerland
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Jerzy Bodurka
- Laureate Institute for Brain Research, Tulsa, OK, USA
| | - Niels Birbaumer
- Institute for Medical Psychology and Behavioural Neurobiology, University of Tübingen, Tübingen, Germany
| | - Olga M Bazanova
- State Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia
| | - Beatrix Barth
- Psychophysiology and Optical Imaging, Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | | | - Tibor Auer
- School of Psychology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Martijn Arns
- Brainclinics Foundation, Research Institute Brainclinics, Nijmegen, The Netherlands
| | - Robert T Thibault
- School of Psychological Science, University of Bristol, Bristol, UK
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
| |
Collapse
|
18
|
Volkova K, Lebedev MA, Kaplan A, Ossadtchi A. Decoding Movement From Electrocorticographic Activity: A Review. Front Neuroinform 2019; 13:74. [PMID: 31849632 PMCID: PMC6901702 DOI: 10.3389/fninf.2019.00074] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 11/14/2019] [Indexed: 01/08/2023] Open
Abstract
Electrocorticography (ECoG) holds promise to provide efficient neuroprosthetic solutions for people suffering from neurological disabilities. This recording technique combines adequate temporal and spatial resolution with the lower risks of medical complications compared to the other invasive methods. ECoG is routinely used in clinical practice for preoperative cortical mapping in epileptic patients. During the last two decades, research utilizing ECoG has considerably grown, including the paradigms where behaviorally relevant information is extracted from ECoG activity with decoding algorithms of different complexity. Several research groups have advanced toward the development of assistive devices driven by brain-computer interfaces (BCIs) that decode motor commands from multichannel ECoG recordings. Here we review the evolution of this field and its recent tendencies, and discuss the potential areas for future development.
Collapse
Affiliation(s)
- Ksenia Volkova
- Center for Bioelectric Interfaces, Higher School of Economics, National Research University, Moscow, Russia
| | - Mikhail A. Lebedev
- Center for Bioelectric Interfaces, Higher School of Economics, National Research University, Moscow, Russia
| | - Alexander Kaplan
- Center for Bioelectric Interfaces, Higher School of Economics, National Research University, Moscow, Russia
- Center for Biotechnology Development, National Research Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
- Laboratory for Neurophysiology and Neuro-Computer Interfaces, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, Higher School of Economics, National Research University, Moscow, Russia
| |
Collapse
|
19
|
Smetanin N, Volkova K, Zabodaev S, Lebedev MA, Ossadtchi A. NFBLab-A Versatile Software for Neurofeedback and Brain-Computer Interface Research. Front Neuroinform 2018; 12:100. [PMID: 30618704 PMCID: PMC6311652 DOI: 10.3389/fninf.2018.00100] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/12/2018] [Indexed: 11/13/2022] Open
Abstract
Neurofeedback (NFB) is a real-time paradigm, where subjects learn to volitionally modulate their own brain activity recorded with electroencephalographic (EEG), magnetoencephalographic (MEG) or other functional brain imaging techniques and presented to them via one of sensory modalities: visual, auditory or tactile. NFB has been proposed as an approach to treat neurological conditions and augment brain functions. Although the early NFB studies date back nearly six decades ago, there is still much debate regarding the efficiency of this approach and the ways it should be implemented. Partly, the existing controversy is due to suboptimal conditions under which the NFB training is undertaken. Therefore, new experimental tools attempting to provide optimal or close to optimal training conditions are needed to further exploration of NFB paradigms and comparison of their effects across subjects and training days. To this end, we have developed open-source NFBLab, a versatile, Python-based software for conducting NFB experiments with completely reproducible paradigms and low-latency feedback presentation. Complex experimental protocols can be configured using the GUI and saved in NFBLab's internal XML-based language that describes signal processing tracts, experimental blocks and sequences including randomization of experimental blocks. NFBLab implements interactive modules that enable individualized EEG/MEG signal processing tracts specification using spatial and temporal filters for feature selection and artifacts removal. NFBLab supports direct interfacing to MNE-Python software to facilitate source-space NFB based on individual head models and properly tailored individual inverse solvers. In addition to the standard algorithms for extraction of brain rhythms dynamics from EEG and MEG data, NFBLab implements several novel in-house signal processing algorithms that afford significant reduction in latency of feedback presentation and may potentially improve training effects. The software also supports several standard BCI paradigms. To interface with external data acquisition devices NFBLab employs Lab Streaming Layer protocol supported by the majority of EEG vendors. MEG devices are interfaced through the Fieldtrip buffer.
Collapse
Affiliation(s)
- Nikolai Smetanin
- Center for Bioelectric Interfaces, National Research University Higher School of Economics, Moscow, Russia
| | - Ksenia Volkova
- Center for Bioelectric Interfaces, National Research University Higher School of Economics, Moscow, Russia
| | | | - Mikhail A Lebedev
- Center for Bioelectric Interfaces, National Research University Higher School of Economics, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, National Research University Higher School of Economics, Moscow, Russia
| |
Collapse
|
20
|
Lebedev MA, Pimashkin A, Ossadtchi A. Navigation Patterns and Scent Marking: Underappreciated Contributors to Hippocampal and Entorhinal Spatial Representations? Front Behav Neurosci 2018; 12:98. [PMID: 29922134 PMCID: PMC5996749 DOI: 10.3389/fnbeh.2018.00098] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/25/2018] [Indexed: 11/29/2022] Open
Abstract
According to the currently prevailing theory, hippocampal formation constructs and maintains cognitive spatial maps. Most of the experimental evidence for this theory comes from the studies on navigation in laboratory rats and mice, typically male animals. While these animals exhibit a rich repertoire of behaviors associated with navigation, including locomotion, head movements, whisking, sniffing, raring and scent marking, the contribution of these behavioral patterns to the hippocampal spatially-selective activity has not been sufficiently studied. Instead, many publications have considered animal position in space as the major variable that affects the firing of hippocampal place cells and entorhinal grid cells. Here we argue that future work should focus on a more detailed examination of different behaviors exhibited during navigation to better understand the mechanism of spatial tuning in hippocampal neurons. As an inquiry in this direction, we have analyzed data from two datasets, shared online, containing recordings from rats navigating in square and round arenas. Our analyses revealed patchy navigation patterns, evident from the spatial maps of animal position, velocity and acceleration. Moreover, grid cells available in the datasets exhibited similar periodicity as the navigation parameters. These findings indicate that activity of grid cells could affect navigation parameters and/or vice versa. Additionally, we speculate that scent marks left by navigating animals could contribute to neuronal responses while rats and mice sniff their environment; the act of sniffing could modulate neuronal discharges even in virtual visual environments. Accordingly, we propose that future experiments should contain additional controls for navigation patterns, whisking, sniffing and maps composed of scent marks.
Collapse
Affiliation(s)
- Mikhail A. Lebedev
- Department of Neurobiology, Duke University, Durham, NC, United States
- Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience of the National Research University Higher School of Economics, Moscow, Russia
| | - Alexey Pimashkin
- Laboratory of Neuroengineering, Center of Translational Technologies, Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience of the National Research University Higher School of Economics, Moscow, Russia
| |
Collapse
|
21
|
Lebedev MA, Ossadtchi A. Commentary: Spatial Olfactory Learning Contributes to Place Field Formation in the Hippocampus. Front Syst Neurosci 2018; 12:8. [PMID: 29692712 PMCID: PMC5902690 DOI: 10.3389/fnsys.2018.00008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/12/2018] [Indexed: 11/18/2022] Open
Affiliation(s)
- Mikhail A Lebedev
- Department of Neurobiology, Duke University, Durham, NC, United States.,Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience of the National Research University Higher School of Economics, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience of the National Research University Higher School of Economics, Moscow, Russia
| |
Collapse
|
22
|
Affiliation(s)
- Mikhail A Lebedev
- Department of Neurobiology, Duke University, Durham, NC, United States.,Center for Bioelectric Interfaces, National Research University Higher School of Economics, Moscow, Russia
| | - Alexei Ossadtchi
- Center for Bioelectric Interfaces, National Research University Higher School of Economics, Moscow, Russia
| |
Collapse
|
23
|
Dagaev N, Volkova K, Ossadtchi A. Latent variable method for automatic adaptation to background states in motor imagery BCI. J Neural Eng 2017; 15:016004. [DOI: 10.1088/1741-2552/aa8065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
24
|
Zubarev I, Klucharev V, Ossadtchi A, Moiseeva V, Shestakova A. MEG Signatures of a Perceived Match or Mismatch between Individual and Group Opinions. Front Neurosci 2017; 11:10. [PMID: 28167897 PMCID: PMC5253388 DOI: 10.3389/fnins.2017.00010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 01/05/2017] [Indexed: 11/13/2022] Open
Abstract
Humans often adjust their opinions to the perceived opinions of others. Neural responses to a perceived match or mismatch between individual and group opinions have been investigated previously, but some findings are inconsistent. In this study, we used magnetoencephalographic source imaging to investigate further neural responses to the perceived opinions of others. We found that group opinions mismatching with individual opinions evoked responses in the anterior and posterior medial prefrontal cortices, as well as in the temporoparietal junction and ventromedial prefrontal cortex in the 220–320 and 380–530 ms time windows. Evoked responses were accompanied by an increase in the power of theta oscillations (4–8 Hz) over a number of frontal cortical sites. Group opinions matching with individual opinions evoked an increase in amplitude of beta oscillations (13–30 Hz) in the anterior cingulate and ventral medial prefrontal cortices. Based on these results, we argue that distinct valuation and performance-monitoring neural circuits in the medial cortices of the brain may monitor compliance of individual behavior to the perceived group norms.
Collapse
Affiliation(s)
- Ivan Zubarev
- Centre for Cognition and Decision Making, National Research University Higher School of EconomicsMoscow, Russia; Department of Neuroscience and Biomedical Engineering, Aalto UniversityEspoo, Finland
| | - Vasily Klucharev
- Centre for Cognition and Decision Making, National Research University Higher School of EconomicsMoscow, Russia; School of Psychology, National Research University Higher School of EconomicsMoscow, Russia
| | - Alexei Ossadtchi
- Centre for Cognition and Decision Making, National Research University Higher School of Economics Moscow, Russia
| | - Victoria Moiseeva
- Centre for Cognition and Decision Making, National Research University Higher School of Economics Moscow, Russia
| | - Anna Shestakova
- Centre for Cognition and Decision Making, National Research University Higher School of Economics Moscow, Russia
| |
Collapse
|
25
|
Kozunov VV, Ossadtchi A. GALA: group analysis leads to accuracy, a novel approach for solving the inverse problem in exploratory analysis of group MEG recordings. Front Neurosci 2015; 9:107. [PMID: 25954141 PMCID: PMC4404950 DOI: 10.3389/fnins.2015.00107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/12/2015] [Indexed: 11/13/2022] Open
Abstract
Although MEG/EEG signals are highly variable between subjects, they allow characterizing systematic changes of cortical activity in both space and time. Traditionally a two-step procedure is used. The first step is a transition from sensor to source space by the means of solving an ill-posed inverse problem for each subject individually. The second is mapping of cortical regions consistently active across subjects. In practice the first step often leads to a set of active cortical regions whose location and timecourses display a great amount of interindividual variability hindering the subsequent group analysis. We propose Group Analysis Leads to Accuracy (GALA)-a solution that combines the two steps into one. GALA takes advantage of individual variations of cortical geometry and sensor locations. It exploits the ensuing variability in electromagnetic forward model as a source of additional information. We assume that for different subjects functionally identical cortical regions are located in close proximity and partially overlap and their timecourses are correlated. This relaxed similarity constraint on the inverse solution can be expressed within a probabilistic framework, allowing for an iterative algorithm solving the inverse problem jointly for all subjects. A systematic simulation study showed that GALA, as compared with the standard min-norm approach, improves accuracy of true activity recovery, when accuracy is assessed both in terms of spatial proximity of the estimated and true activations and correct specification of spatial extent of the activated regions. This improvement obtained without using any noise normalization techniques for both solutions, preserved for a wide range of between-subject variations in both spatial and temporal features of regional activation. The corresponding activation timecourses exhibit significantly higher similarity across subjects. Similar results were obtained for a real MEG dataset of face-specific evoked responses.
Collapse
Affiliation(s)
- Vladimir V Kozunov
- MEG Centre, Moscow State University of Psychology and Education Moscow, Russia
| | - Alexei Ossadtchi
- Centre for Cognition and Decision Making, National Research University Higher School of Economics Moscow, Russia ; Laboratory of Control of Complex Systems, Institute of Problems of Mechanical Engineering Russian Academy of Sciences St. Petersburg, Russia
| |
Collapse
|
26
|
Ossadtchi A, Pronko P, Baillet S, Pflieger ME, Stroganova T. Mutual information spectrum for selection of event-related spatial components. Application to eloquent motor cortex mapping. Front Neuroinform 2014; 7:53. [PMID: 24478692 PMCID: PMC3895937 DOI: 10.3389/fninf.2013.00053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/31/2013] [Indexed: 11/13/2022] Open
Abstract
Spatial component analysis is often used to explore multidimensional time series data whose sources cannot be measured directly. Several methods may be used to decompose the data into a set of spatial components with temporal loadings. Component selection is of crucial importance, and should be supported by objective criteria. In some applications, the use of a well defined component selection criterion may provide for automation of the analysis. In this paper we describe a novel approach for ranking of spatial components calculated from the EEG or MEG data recorded within evoked response paradigm. Our method is called Mutual Information (MI) Spectrum and is based on gauging the amount of MI of spatial component temporal loadings with a synthetically created reference signal. We also describe the appropriate randomization based statistical assessment scheme that can be used for selection of components with statistically significant amount of MI. Using simulated data with realistic trial to trial variations and SNR corresponding to the real recordings we demonstrate the superior performance characteristics of the described MI based measure as compared to a more conventionally used power driven gauge. We also demonstrate the application of the MI Spectrum for the selection of task-related independent components from real MEG data. We show that the MI spectrum allows to identify task-related components reliably in a consistent fashion, yielding stable results even from a small number of trials. We conclude that the proposed method fits naturally the information driven nature of ICA and can be used for routine and automatic ranking of independent components calculated from the functional neuroimaging data collected within event-related paradigms.
Collapse
Affiliation(s)
- Alexei Ossadtchi
- Department of Higher Nervous Activity and Psychophysiology, St. Petersburg State University St. Petersburg, Russia ; Laboratory of Decision Making, National Research University Higher School of Economics Moscow, Russia ; Complex Systems Control Laboratory, Institute for Problems of Mechanical Engineering RAS, St. Petersburg, Russia
| | - Platon Pronko
- Laboratory of Cognitive Psychophysiology, National Research University Higher School of Economics Moscow, Russia
| | - Sylvain Baillet
- Dynamic Neuroimaging Laboratory, McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University Montreal, QC, Canada
| | | | - Tatiana Stroganova
- MEG Centre, Moscow State University of Psychology and Education Moscow, Russia
| |
Collapse
|
27
|
Abstract
For patients with partial epilepsy, automatic spike detection techniques applied to interictal MEG data often discover several potentially epileptogenic brain regions. An important determination in treatment planning is which of these detected regions are most likely to be the primary sources of epileptogenic activity. Analysis of the patterns of propagation activity between the detected regions may allow for detection of these primary epileptic foci. We describe the use of hidden Markov models (HMM) for estimation of the propagation patterns between several spiking regions from interictal MEG data. Analysis of the estimated transition probability matrix allows us to make inferences regarding the propagation pattern of the abnormal activity and determine the most likely region of its origin. The proposed HMM paradigm allows for a simple incorporation of the spike detector specificity and sensitivity characteristics. We develop bounds on performance for the case of perfect detection. We also apply the technique to simulated data sets in order to study the robustness of the method to the non-ideal specificity-sensitivity characteristics of the event detectors and compare results with the lower bounds. Our study demonstrates robustness of the proposed technique to event detection errors. We conclude with an example of the application of this method to a single patient.
Collapse
Affiliation(s)
- A Ossadtchi
- Source Signal Imaging Inc., San Diego, CA 92103, USA
| | | | | | | | | |
Collapse
|
28
|
Ossadtchi A, Baillet S, Mosher JC, Thyerlei D, Sutherling W, Leahy RM. Automated interictal spike detection and source localization in magnetoencephalography using independent components analysis and spatio-temporal clustering. Clin Neurophysiol 2004; 115:508-22. [PMID: 15036046 DOI: 10.1016/j.clinph.2003.10.036] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2003] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Magnetoencephalography (MEG) dipole localization of epileptic spikes is useful in epilepsy surgery for mapping the extent of abnormal cortex and to focus intracranial electrodes. Visually analyzing large amounts of data produces fatigue and error. Most automated techniques are based on matching of interictal spike templates or predictive filtering of the data and do not explicitly include source localization as part of the analysis. This leads to poor sensitivity versus specificity characteristics. We describe a fully automated method that combines time-series analysis with source localization to detect clusters of focal neuronal current generators within the brain that produce interictal spike activity. METHODS We first use an ICA (independent components analysis) method to decompose the multichannel MEG data and identify those components that exhibit spike-like characteristics. From these detected spikes we then find those whose spatial topographies across the array are consistent with focal neural sources, and determine the foci of equivalent current dipoles and their associated time courses. We then perform a clustering of the localized dipoles based on distance metrics that takes into consideration both their locations and time courses. The final step of refinement consists of retaining only those clusters that are statistically significant. The average locations and time series from significant clusters comprise the final output of our method. RESULTS AND SIGNIFICANCE Data were processed from 4 patients with partial focal epilepsy. In all three subjects for whom surgical resection was performed, clusters were found in the vicinity of the resectioned area. CONCLUSIONS The presented procedure is promising and likely to be useful to the physician as a more sensitive, automated and objective method to help in the localization of the interictal spike zone of intractable partial seizures. The final output can be visually verified by neurologists in terms of both the location and distribution of the dipole clusters and their associated time series. Due to the clinical relevance and demonstrated promise of this method, further investigation of this approach is warranted.
Collapse
Affiliation(s)
- A Ossadtchi
- Department of Electrical Engineering, Signal and Image Processing Institute, University of Southern California, 3740 McClintock Avenue, Los Angeles, CA 90089, USA
| | | | | | | | | | | |
Collapse
|