On December 2, the thesis was successfully defended!
Alexandra Koptelova, research fellow of the MEG-Center, has successfully defended her thesis for the degree PhD in Biological!
Нейрофизиологические механизмы и нейромаркёры активности эпилептогенных зон у пациентов с фармакорезистентной эпилепсией - магнитоэнцефалографическое исследование
prof. Karl John Friston
a British neuroscientist and authority on brain imaging has held lectures and master classes at Moscow State University of Psychology and Education and Higher School of Economics
23.09.2019 there was an open lecture on
24.09.2019 a master-class took place on
25.09.2019 a master-class was held on
26.09.2019 a master-class took place on
16.09.2019 a seminar was held on
When and where in the brain prior knowledge affects visual processing in a way that makes possible of object recognition
by Vladimir Kozunov, research fellow of the MEG-Center
A core assumption of cognitive neuroscience is that during visual perception the brain processes a stimulation at various levels progressing from those closely tied to visual features of the stimuli to increasingly more abstract representations. One of the most intriguing puzzles of this process is the acquisition of meaning that is tied to a mental representation, of which stimulus does not possess without reference to the internal state of the observer. As a solution to this issue it has been suggested that perception is not only determined by the bottom-up flow of information that our sensory organs encode of the outside world and send to higher levels, but also strongly depends on prior knowledge that is already present in the brain and affects in top-down direction. This however raises a new question: how and where are these top-down processes, that provide meaning to visual percepts, initiated.
In the present study we used the magnetoencephalography (MEG) to record cortical activity and applied both a region-based multivariate pattern classiﬁcation analysis and a temporal generalization cross-decoding analysis to investigate spatiotemporal patterns of neural activity underlying visual perception of stimuli. We manipulated the possibility of recognition of these stimuli depending on prior knowledge available to the observer. To do this, we used Mooney images that have been specially processed so that when seeing them for the first time the observer only perceives a meaningless pattern but after a short period of training he (she) can recognize a meaningful object in the image. This experimental design provides a very attractive perspective to study experience-dependent brain states that influence perception with a top-down bias, because when presenting the same image before and after training, the external input the brain receives is exactly the same but the knowledge available to the observer is different. After training, the brain is able to change the way it appreciates different features in the image and so provides high-level predictions. In order to investigate differential characteristics of top-down influences for categories that are shaped predominantly by either value-dependent or functionally-based experience we used images of two classes of objects, faces and tools. We have found training induced changes in neuronal activity both in brain areas processing visual features and in the value system regions, which speaks in favor of value dependent mapping between visual cues and meaning-based predictions.
18.04.2019 a seminar was held on
Magnetoencephalography in presurgical evaluation of pharmacoresistant epilepsy patients. Implementation into Russian epilepsy surgery practice. Common and added clinical values
by Alexandra Koptelova, research fellow of the MEG-Center
In one third of epilepsy patients pharmacotherapy are doomed to fail. In cases of a focal seizure onset, epilepsy surgery has been shown to be superior to continued medical treatment. Surgical success depends on the exact definition of the epileptogenic zone (EZ) and its surgical accessibility. Magnetoencephalography (MEG) is one of the newer additions to the presurgical work-up of pharmacoresistant epilepsy patients, especially in Russia. This lecture will focus on the results of 8-years applying this noninvasive technique to neurosurgery practice in Russia. In collaboration with Burdenko Neurosurgery Institute and Russian Children Clinical Hospital we collected and analyzed the data more than 150 epilepsy patients with uncertain final hypothesis of EZ localization. About third of patients underwent to epilepsy surgery. In all cases our data were applied to planning of invasive investigations and surgery strategy. So, our data were subjected to strict clinical verification. In a half of patients, we registered seizure during MEG data collection, that uncommon for world practice. What is clinical relevance of MEG? Is MEG superior than scalp EEG in detection of epileptiform activity and for what cortical regions EEG could be blind? What can give us interictal data analysis? Which new and critical information provides preictal MEG data? All these questions will be mentioned in lecture.
16.04.2019 a seminar was held on
one of the Skoltech CDISE projects
Доклад посвящен одному из проектов Skoltech CDISE, имеющему своей целью развитие методик магнитной и электрической энцефалографий. Мы расскажем о новых методах МЭГ/ЭЭГ, которые развиваются в Сколтехе, обсудим проблемы существующих подходов и способы преодоления некоторых из них, поговорим про новые аппаратные и программные решения, а также про некоторые математические аспекты моделирования и обработки данных МЭГ/ЭЭГ. Акцент будет сделан на возможном сотрудничестве Skoltech и МЭГ-центра по части МЭГ.
15.03.2019 a seminar was held on
Необычный человеко-машинный интерфейс на основе айтрекинга, МЭГ и ЭЭГ
by Sergei L. Shishkin, candidate of biological Sciences, Head of the Laboratory for Neuroergonomics and Brain-Computer Interfaces, National Research Centre "Kurchatov Institute"
Семинар был посвящен проекту, поддержанному РНФ и выполняющемуся на базе МЭГ-центра. Проект нацелен на создание и экспериментальную реализацию методики распознавания намерений, которая, как предполагается, впервые в истории неинвазивного человеко-машинного взаимодействия даст человеку возможность активно взаимодействовать с компьютером, управляя им практически без каких-либо усилий и в обход обычной эффекторной системы. Мы поговорили о том, в чем состоит практический смысл создания такой сугубо лабораторной модели человеко-машинного интерфейса, что можно попытаться попутно узнать в ходе этой работы о формировании и реализации намерений, какие результаты уже получены и что еще будет важно сделать в этом и следующем году.
27.02.2019 a seminar was held on
the results of experiments, codenamed "Broca", related projects and areas of future research
by Anna Pavlova, research assistant of the MEG-Center
Мы обсудили, как меняется ответ мозга при чтении существительного, когда мы не просто читаем его про себя, но пытаемся подобрать глагол, отвечающий на вопрос - "Что это существительное делает?" (например, что делает солнце?). Мы поговорили, как различаются ситуации, когда такой глагол находится легко и просто (солнце, конечно, светит) и когда глагол находится с трудом (что вообще делает подоконник???), и какие зоны мозга участвуют в решении этой задачи (нет, о зоне Брока мы не говорили).
19.02.2019 a seminar was held on
EEG and MEG studies of brain mechanisms of cognitive control using time-frequency analysis
by Boris V Chernyshev, associate Professor, candidate of biological Sciences, Head of the MEG-Center, associate Professor of the Department, MSU
Cognitive control is a set of processes that are responsible for flexible goal-directed behaviour. It can be viewed as an interplay between two constituent aspects: maintenance of task-specific processes related to attention, and non-specific regulation of motor threshold, both of them having strong influence on response accuracy and response time. Failures in each system lead to different types of errors, associated either with attentional lapses and uncertainty, or with dysfunction of the motor threshold. Performance monitoring and outcome prediction are also basic processes involved in cognitive control.
We did a series of EEG experiments during the auditory condensation task, which is highly demanding for sustained attention. We analyzed EEG oscillations in theta, alpha and beta bands.
In the first study, we used data-driven approach to capture basic brain networks involved in cognitive control. The results of this study indicate that adaptive adjustments after errors are implemented by the frontal-medial network of task performance monitoring, the parietal attentional network and the sensorimotor network.
In the second study, we aimed to find out if response time could be a valid approximation distinguishing trials with high and low levels of attention and decision uncertainty. We focused on response-related and feedback-related modulations, since “internal” response-related outcome detection is likely in conditions of attention and certainly, while “external” feedback-related outcome detection is more likely in conditions of inattention and uncertainty. The analysis of theta, alpha and beta oscillations confirmed our hypotheses.
In the third study, we used a task that involved complex stimulus-to-response mapping that was acquired by participants in the course of "trial-and-error" learning. We analyzed correct and erroneous responses at the early stage of learning, as well as the correct responses at a later stage of learning characterized by a high level of task performance. In contrast to studies using EEG, this MEG study revealed a distributed cortical network of theta oscillation sources that extended far beyond midfrontal areas. The data obtained confirmed the existence of two components of the prediction error: the early component of the response to the feedback signal corresponded to the component of the “unsigned” prediction error, while the late component of the response to the feedback signal reflected the “unsigned” prediction error. This study demonstrated the applicability of MEG for studying theta oscillations as a correlate of cognitive control processes.
13.02.2019 a seminar was held on
«Gamma oscillations and excitation/inhibition balance in the brain»
by Elena V Orekhova, doctor of psychology, leading researcher, National MEG-Center, leading researcher, University of Gothenburg
Gamma frequency oscillations (30 to 100 Hz) are ubiquitous in the brain and involved in multiple cognitive and perceptual processes. While the role of gamma oscillations as a basic mechanism of information processing is still debated, researchers generally agree that these oscillations may provide useful information on excitation/inhibition interactions in the brain. This has important clinical implications, since gamma-range activity can be noninvasively recorded by magnetoencephalography (MEG) and can potentially help to assess the excitation/inhibition balance in brain disorders. It is however still unclear what parameters of the gamma waves are most relevant. In a series of studies we investigated how visual gamma oscillations are modulated by the strength of excitatory drive and how these modulations are related to behavioral indexes of neural inhibition. Our results suggest that stimulation-related changes in gamma oscillations, rather then absolute vales of their frequency or amplitude, give important information about the capacity of inhibitory networks to regulate the excitation/inhibition balance in healthy and diseased brain. In this presentation I will shortly tell about phenomenon of gamma oscillations and then present findings of our group.
05.02.2019 a seminar was held on
«Epilepsy surgery driven by innovative biomarkers and cognitive assessment of specific brain functions»
by Tommaso Fedele, Assistant professor, Institute of Cognitive Neuroscience Higher School of Economics - National Research University
Nowadays, about one third of epilepsy patients are refractory to pharmacological treatment, becoming candidate for surgical intervention. Surgical planning faces two major problems: 1) the correct identification the epileptogenic zone, which is frequently adjacent to but often not identical with the epileptogenic lesion, and its differentiation from functional brain tissue, which should be preserved during surgery; 2) the evaluation of the post-operative cognitive deficit, which depends on the residual functionality of the resected area. Beside medical and technological advances in the field of epilepsy surgery, reliable biomarkers guiding optimal resection of the epileptogenic zone are still lacking. Moreover, the neurophysiological evaluation of residual functionality in the epileptic brain is still poorly investigated.
In the past years I contributed to validate high frequency oscillations (HFO) in the intracranial EEG as an innovative biomarker for the delineation of the epileptogenic zone. While HFO are detected in the macro-scale EEG, known as local field potential, we combined routine clinical recordings with multi-unit neuronal activity and evaluated the relation between HFO and single unit activity in human tissue in vivo. In order to control for potential post-surgical cognitive deficit, we investigated the neurophysiological response during a set of cognitive paradigms. In this seminar I will present published results and ongoing analysis on intracranial EEG recording which are of interest to the clinical, neurophysiological an cognitive domain.
I will also present the project framework I plan to establish here in Moscow. We aim to perform clinical and cognitive assessment of pharmaco-resistant epilepsy patients designated for intracranial encephalography (iEEG) to guide surgical planning. The patients participating to our study will be first recorded in the magnetoencephalography (MEG) before receiving the stereo-iEEG implantation, then a similar set of recording will be performed after implantation in the intensive monitoring unit in the clinical institute. The output of our analysis will support the clinical evaluation and minimize post-operative cognitive deficit on single patient basis.