Jacek Rogala - Academia.edu (original) (raw)

Papers by Jacek Rogala

Research paper thumbnail of Challenges facing the explainability of age prediction models: case study for two modalities

arXiv (Cornell University), Mar 12, 2023

Research paper thumbnail of Reciprocal inhibition and slow calcium decay in perigeniculate interneurons explain changes of spontaneous firing of thalamic cells caused by cortical inactivation

Frontiers in Computational Neuroscience, 2012

The role of cortical feedback in the thalamocortical processing loop has been extensively investi... more The role of cortical feedback in the thalamocortical processing loop has been extensively investigated over the last decades. With an exception of several cases, these searches focused on the cortical feedback exerted onto thalamo-cortical relay (TC) cells of the dorsal lateral geniculate nucleus (LGN). In a previous, physiological study, we showed in the cat visual system that cessation of cortical input, despite decrease of spontaneous activity of TC cells, increased spontaneous firing of their recurrent inhibitory interneurons located in the perigeniculate nucleus (PGN). To identify mechanisms underlying such functional changes we conducted a modeling study in NEURON on several networks of point neurons with varied model parameters, such as membrane properties, synaptic weights and axonal delays. We considered six network topologies of the retino-geniculo-cortical system. All models were robust against changes of axonal delays except for the delay between the LGN feed-forward interneuron and the TC cell. The best representation of physiological results was obtained with models containing reciprocally connected PGN cells driven by the cortex and with relatively slow decay of intracellular calcium. This strongly indicates that the thalamic reticular nucleus plays an essential role in the cortical influence over thalamo-cortical relay cells while the thalamic feed-forward interneurons are not essential in this process. Further, we suggest that the dependence of the activity of PGN cells on the rate of calcium removal can be one of the key factors determining individual cell response to elimination of cortical input.

Research paper thumbnail of Impact of EEG Frequency Bands and Data Separation on the Performance of Person Verification Employing Neural Networks

Sensors

The paper is devoted to the study of EEG-based people verification. Analyzed solutions employed s... more The paper is devoted to the study of EEG-based people verification. Analyzed solutions employed shallow artificial neural networks using spectral EEG features as input representation. We investigated the impact of the features derived from different frequency bands and their combination on verification results. Moreover, we studied the influence of a number of hidden neurons in a neural network. The datasets used in the analysis consisted of signals recorded during resting state from 29 healthy adult participants performed on different days, 20 EEG sessions for each of the participants. We presented two different scenarios of training and testing processes. In the first scenario, we used different parts of each recording session to create the training and testing datasets, and in the second one, training and testing datasets originated from different recording sessions. Among single frequency bands, the best outcomes were obtained for the beta frequency band (mean accuracy of 91 and...

Research paper thumbnail of Stronger connectivity and higher extraversion protect against stress-related deterioration of cognitive functions

Scientific Reports, 2021

Here we attempted to define the relationship between: EEG activity, personality and coping during... more Here we attempted to define the relationship between: EEG activity, personality and coping during lockdown. We were in a unique situation since the COVID-19 outbreak interrupted our independent longitudinal study. We already collected a significant amount of data before lockdown. During lockdown, a subgroup of participants willingly continued their engagement in the study. These circumstances provided us with an opportunity to examine the relationship between personality/cognition and brain rhythms in individuals who continued their engagement during lockdown compared to control data collected well before pandemic. The testing consisted of a one-time assessment of personality dimensions and two sessions of EEG recording and deductive reasoning task. Participants were divided into groups based on the time they completed the second session: before or during the COVID-19 outbreak ‘Pre-pandemic Controls’ and ‘Pandemics’, respectively. The Pandemics were characterized by a higher extrave...

Research paper thumbnail of Spectral analysis versus signal complexity methods for assessing attention related activity in human EEG

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2019

We aimed to find the most effective analytical method for assessment of attention related activit... more We aimed to find the most effective analytical method for assessment of attention related activity to be used in neurofeedback training. We compared commonly used spectral EEG methods with those measuring signal complexity - based on calculation of entropy and fractal dimension. The 14 subjects were examined with a modified delayed matching-to-sample task. All investigated methods revealed significant differences of EEG signals recorded in control and attentional trials, however the selection of signals with such differences varied between subjects and applied methods. The results indicated: (i) the importance of the individual analysis of signals from each subject and session, (ii) benefits of applying signal complexity methods to support spectral analysis in a further application and (iii) an advantage of the signal complexity method, carrying information of assembles of spectral components, over common spectral methods.

Research paper thumbnail of Amplitude of the resting state beta band oscillations predicts erp characteristics and behavioural performance during attention tasks

Acta Neurobiologiae Experimentalis, 2018

Research paper thumbnail of Muscle activity can fake the effect of high-frequency EEG-neurofeedback

Acta Neurobiologiae Experimentalis, 2015

Research paper thumbnail of EEG estimates of attentional control during modified multi-source interference task (MSIT+)

Acta Neurobiologiae Experimentalis, 2018

Research paper thumbnail of Experimental studies on the efficiency of people authentication using EEG data from the same and different examinations

2021 Signal Processing Symposium (SPSympo), 2021

The paper presents the results of preliminary studies on the authentication of human subjects usi... more The paper presents the results of preliminary studies on the authentication of human subjects using electroencephalography (EEG) signals. Many research results in the literature assume that the data used both for training and testing may come from the same set. In this work, we verified how the authentication results change if the data used for training and testing are from separated recording sessions. The examinations used in the studies were collected from 36 healthy adults and 20 EEG sessions were planned for each person. We evaluated the statistical metrics of the considered authentication methods based on the analysis of signal features (parameters) from different EEG bands: separately for delta, theta, alpha, beta, and gamma, as well as for the combinations of features from the different EEG bands. In the first approach, the first 15 examinations from each participant were used for training and the remaining 5 for testing. In the second approach, 75 % of features from each session were used for training and the remaining 25 % for testing. The results show that the statistical metrics of authentication analysis obtained using signals from the same set, both for training and testing, turned out to be better than when we split the data using individual sets for training and examination. In practice, the authentication is performed based on a current examination, different from the ones used for training. Therefore, for the proper evaluation of the authentication methods, only the metrics obtained when the examinations used for training and testing are separated should be used. The results also suggest that there are significant statistical differences in accuracy and sensitivity between the two approaches.

Research paper thumbnail of A hidden message: Decoding artistic intent

PsyCh Journal, 2020

Understanding how art makes impressions upon the perceiver has been a fundamental topic of philos... more Understanding how art makes impressions upon the perceiver has been a fundamental topic of philosophical interest since the time of ancient Greece. However, the extent of artistic perception and aesthetic appreciation has been the topic of empirical studies only recently, following the emergence of psychology as an independent field of science. The present study discusses the hypothesis that the impression created by artwork on the viewer can be predicted by examining activity of neuronal networks. In particular, we focus on neural activity evoked by abstract stimuli that matches elements of the viewers' previously learned conceptual dictionary. We show that artistic appreciation fundamentally depends on how easily the author's intent expressed in his or her artwork can be abstracted and decoded, on a neuronal level, into new or merged concept networks. More diverse intellectual and personal experiences-and their corollary neural networks-may facilitate the creation of new networks. These new networks, in turn, modulate the extent to which art can be apprehended and appreciated.

Research paper thumbnail of Resting-state EEG activity predicts frontoparietal network reconfiguration and improved attentional performance

Scientific Reports, 2020

Mounting evidence indicates that resting-state EEG activity is related to various cognitive funct... more Mounting evidence indicates that resting-state EEG activity is related to various cognitive functions. To trace physiological underpinnings of this relationship, we investigated EEG and behavioral performance of 36 healthy adults recorded at rest and during visual attention tasks: visual search and gun shooting. All measures were repeated two months later to determine stability of the results. Correlation analyses revealed that within the range of 2–45 Hz, at rest, beta-2 band power correlated with the strength of frontoparietal connectivity and behavioral performance in both sessions. Participants with lower global beta-2 resting-state power (gB2rest) showed weaker frontoparietal connectivity and greater capacity for its modifications, as indicated by changes in phase correlations of the EEG signals. At the same time shorter reaction times and improved shooting accuracy were found, in both test and retest, in participants with low gB2rest compared to higher gB2rest values. We posit...

Research paper thumbnail of EEG-neurofeedback training of beta band (12-22Hz) affects alpha and beta frequencies - A controlled study of a healthy population

Neuropsychologia, Jan 8, 2018

The frequency-function relation of various EEG bands has inspired EEG-neurofeedback procedures in... more The frequency-function relation of various EEG bands has inspired EEG-neurofeedback procedures intending to improve cognitive abilities in numerous clinical groups. In this study, we administered EEG-neurofeedback (EEG-NFB) to a healthy population to determine the efficacy of this procedure. We evaluated feedback manipulation in the beta band (12-22Hz), known to be involved in visual attention processing. Two groups of healthy adults were trained to either up- or down-regulate beta band activity, thus providing mutual control. Up-regulation training induced increases in beta and alpha band (8-12Hz) amplitudes during the first three sessions. Group-independent increases in the activity of both bands were observed in the later phase of training. EEG changes were not matched by measured behavioural indices of attention. Parallel changes in the two bands challenge the idea of frequency-specific EEG-NFB protocols and suggest their interdependence. Our study exposes the possibility (i) th...

Research paper thumbnail of Beware: Recruitment of Muscle Activity by the EEG-Neurofeedback Trainings of High Frequencies

Frontiers in Human Neuroscience, 2017

EEG-neurofeedback (NFB) became a very popular method aimed at improving cognitive and behavioral ... more EEG-neurofeedback (NFB) became a very popular method aimed at improving cognitive and behavioral performance. However, the EMG frequency spectrum overlies the higher EEG oscillations and the NFB trainings focusing on these frequencies is hindered by the problem of EMG load in the information fed back to the subjects. In such a complex signal, it is highly probable that the most controllable component will form the basis for operant conditioning. This might cause different effects in the case of various training protocols and therefore needs to be carefully assessed before designing training protocols and algorithms. In the current experiment a group of healthy adults (n = 14) was trained by professional trainers to up-regulate their beta1 (15-22 Hz) band for eight sessions. The control group (n = 18) underwent the same training regime but without rewards for increasing beta. In half of the participants trained to up-regulate beta1 band (n = 7) a systematic increase in tonic EMG activity was identified offline, implying that muscle activity became a foundation for reinforcement in the trainings. The remaining participants did not present any specific increase of the trained beta1 band amplitude. The training was perceived effective by both trainers and the trainees in all groups. These results indicate the necessity of proper control of muscle activity as a requirement for the genuine EEG-NFB training, especially in protocols that do not aim at the participants' relaxation. The specificity of the information fed back to the participants should be of highest interest to all therapists and researchers, as it might irreversibly alter the results of the training.

Research paper thumbnail of The Do's and Don'ts of Neurofeedback Training: A Review of the Controlled Studies Using Healthy Adults

Frontiers in Human Neuroscience, 2016

The goal of EEG neurofeedback (EEG-NFB) training is to induce changes in the power of targeted EE... more The goal of EEG neurofeedback (EEG-NFB) training is to induce changes in the power of targeted EEG bands to produce beneficial changes in cognitive or motor function. The effectiveness of different EEG-NFB protocols can be measured using two dependent variables: (1) changes in EEG activity and (2) behavioral changes of a targeted function (for therapeutic applications the desired changes should be long-lasting). To firmly establish a causal link between these variables and the selected protocol, similar changes should not be observed when appropriate control paradigms are used. The main objective of this review is to evaluate the evidence, reported in the scientific literature, which supports the validity of various EEG-NFB protocols. Our primary concern is to highlight the role that uncontrolled nonspecific factors can play in the results generated from EEG-NFB studies. Nonspecific factors are often ignored in EEG-NFB designs or the data are not presented, which means conclusions should be interpreted cautiously. As an outcome of this review we present a do's and don'ts list, which can be used to develop future EEG-NFB methodologies, based on the small set of experiments in which the proper control groups have excluded non-EEG-NFB related effects. We found two features which positively correlated with the expected changes in power of the trained EEG band(s): (1) protocols which focused on training a smaller number of frequency bands and (2) a bigger number of electrodes used for neurofeedback training. However, we did not find evidence in support of the positive relationship between power changes of a trained frequency band(s) and specific behavioral effects.

Research paper thumbnail of The grounds for successful neurofeedback

Research paper thumbnail of Effect of cortex inactivation on spontaneous activity of cells in perigeniculate and dorsal lateral geniculate nuclei

BMC Neuroscience, 2013

Figure 1 Effect of cortex cooling on activity of PGN and LGN cells. A. Percent of change in relat... more Figure 1 Effect of cortex cooling on activity of PGN and LGN cells. A. Percent of change in relation to situation when the cortex was active. B. Percent of significant differences (p < 0.05). IBISI-intra burst ISI, SPB-spikes per burst, BD-burst duration, ISI-mean ISI, FR-firing rate, BRbursting rate.

Research paper thumbnail of Cortical modulation of neuronal activity in the cat's lateral geniculate and perigeniculate nuclei: a modeling study

Research paper thumbnail of Decoding working memory-related information from repeated psychophysiological EEG experiments using convolutional and contrastive neural networks

Journal of Neural Engineering

Objective. Extracting reliable information from electroencephalogram (EEG) is difficult because t... more Objective. Extracting reliable information from electroencephalogram (EEG) is difficult because the low signal-to-noise ratio and significant intersubject variability seriously hinder statistical analyses. However, recent advances in explainable machine learning open a new strategy to address this problem. Approach. The current study evaluates this approach using results from the classification and decoding of electrical brain activity associated with information retention. We designed four neural network models differing in architecture, training strategies, and input representation to classify single experimental trials of a working memory task. Main results. Our best models achieved an accuracy (ACC) of 65.29 ± 0.76 and Matthews correlation coefficient of 0.288 ± 0.018, outperforming the reference model trained on the same data. The highest correlation between classification score and behavioral performance was 0.36 (p = 0.0007). Using analysis of input perturbation, we estimated...

Research paper thumbnail of Challenges facing the explainability of age prediction models: case study for two modalities

arXiv (Cornell University), Mar 12, 2023

Research paper thumbnail of Reciprocal inhibition and slow calcium decay in perigeniculate interneurons explain changes of spontaneous firing of thalamic cells caused by cortical inactivation

Frontiers in Computational Neuroscience, 2012

The role of cortical feedback in the thalamocortical processing loop has been extensively investi... more The role of cortical feedback in the thalamocortical processing loop has been extensively investigated over the last decades. With an exception of several cases, these searches focused on the cortical feedback exerted onto thalamo-cortical relay (TC) cells of the dorsal lateral geniculate nucleus (LGN). In a previous, physiological study, we showed in the cat visual system that cessation of cortical input, despite decrease of spontaneous activity of TC cells, increased spontaneous firing of their recurrent inhibitory interneurons located in the perigeniculate nucleus (PGN). To identify mechanisms underlying such functional changes we conducted a modeling study in NEURON on several networks of point neurons with varied model parameters, such as membrane properties, synaptic weights and axonal delays. We considered six network topologies of the retino-geniculo-cortical system. All models were robust against changes of axonal delays except for the delay between the LGN feed-forward interneuron and the TC cell. The best representation of physiological results was obtained with models containing reciprocally connected PGN cells driven by the cortex and with relatively slow decay of intracellular calcium. This strongly indicates that the thalamic reticular nucleus plays an essential role in the cortical influence over thalamo-cortical relay cells while the thalamic feed-forward interneurons are not essential in this process. Further, we suggest that the dependence of the activity of PGN cells on the rate of calcium removal can be one of the key factors determining individual cell response to elimination of cortical input.

Research paper thumbnail of Impact of EEG Frequency Bands and Data Separation on the Performance of Person Verification Employing Neural Networks

Sensors

The paper is devoted to the study of EEG-based people verification. Analyzed solutions employed s... more The paper is devoted to the study of EEG-based people verification. Analyzed solutions employed shallow artificial neural networks using spectral EEG features as input representation. We investigated the impact of the features derived from different frequency bands and their combination on verification results. Moreover, we studied the influence of a number of hidden neurons in a neural network. The datasets used in the analysis consisted of signals recorded during resting state from 29 healthy adult participants performed on different days, 20 EEG sessions for each of the participants. We presented two different scenarios of training and testing processes. In the first scenario, we used different parts of each recording session to create the training and testing datasets, and in the second one, training and testing datasets originated from different recording sessions. Among single frequency bands, the best outcomes were obtained for the beta frequency band (mean accuracy of 91 and...

Research paper thumbnail of Stronger connectivity and higher extraversion protect against stress-related deterioration of cognitive functions

Scientific Reports, 2021

Here we attempted to define the relationship between: EEG activity, personality and coping during... more Here we attempted to define the relationship between: EEG activity, personality and coping during lockdown. We were in a unique situation since the COVID-19 outbreak interrupted our independent longitudinal study. We already collected a significant amount of data before lockdown. During lockdown, a subgroup of participants willingly continued their engagement in the study. These circumstances provided us with an opportunity to examine the relationship between personality/cognition and brain rhythms in individuals who continued their engagement during lockdown compared to control data collected well before pandemic. The testing consisted of a one-time assessment of personality dimensions and two sessions of EEG recording and deductive reasoning task. Participants were divided into groups based on the time they completed the second session: before or during the COVID-19 outbreak ‘Pre-pandemic Controls’ and ‘Pandemics’, respectively. The Pandemics were characterized by a higher extrave...

Research paper thumbnail of Spectral analysis versus signal complexity methods for assessing attention related activity in human EEG

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2019

We aimed to find the most effective analytical method for assessment of attention related activit... more We aimed to find the most effective analytical method for assessment of attention related activity to be used in neurofeedback training. We compared commonly used spectral EEG methods with those measuring signal complexity - based on calculation of entropy and fractal dimension. The 14 subjects were examined with a modified delayed matching-to-sample task. All investigated methods revealed significant differences of EEG signals recorded in control and attentional trials, however the selection of signals with such differences varied between subjects and applied methods. The results indicated: (i) the importance of the individual analysis of signals from each subject and session, (ii) benefits of applying signal complexity methods to support spectral analysis in a further application and (iii) an advantage of the signal complexity method, carrying information of assembles of spectral components, over common spectral methods.

Research paper thumbnail of Amplitude of the resting state beta band oscillations predicts erp characteristics and behavioural performance during attention tasks

Acta Neurobiologiae Experimentalis, 2018

Research paper thumbnail of Muscle activity can fake the effect of high-frequency EEG-neurofeedback

Acta Neurobiologiae Experimentalis, 2015

Research paper thumbnail of EEG estimates of attentional control during modified multi-source interference task (MSIT+)

Acta Neurobiologiae Experimentalis, 2018

Research paper thumbnail of Experimental studies on the efficiency of people authentication using EEG data from the same and different examinations

2021 Signal Processing Symposium (SPSympo), 2021

The paper presents the results of preliminary studies on the authentication of human subjects usi... more The paper presents the results of preliminary studies on the authentication of human subjects using electroencephalography (EEG) signals. Many research results in the literature assume that the data used both for training and testing may come from the same set. In this work, we verified how the authentication results change if the data used for training and testing are from separated recording sessions. The examinations used in the studies were collected from 36 healthy adults and 20 EEG sessions were planned for each person. We evaluated the statistical metrics of the considered authentication methods based on the analysis of signal features (parameters) from different EEG bands: separately for delta, theta, alpha, beta, and gamma, as well as for the combinations of features from the different EEG bands. In the first approach, the first 15 examinations from each participant were used for training and the remaining 5 for testing. In the second approach, 75 % of features from each session were used for training and the remaining 25 % for testing. The results show that the statistical metrics of authentication analysis obtained using signals from the same set, both for training and testing, turned out to be better than when we split the data using individual sets for training and examination. In practice, the authentication is performed based on a current examination, different from the ones used for training. Therefore, for the proper evaluation of the authentication methods, only the metrics obtained when the examinations used for training and testing are separated should be used. The results also suggest that there are significant statistical differences in accuracy and sensitivity between the two approaches.

Research paper thumbnail of A hidden message: Decoding artistic intent

PsyCh Journal, 2020

Understanding how art makes impressions upon the perceiver has been a fundamental topic of philos... more Understanding how art makes impressions upon the perceiver has been a fundamental topic of philosophical interest since the time of ancient Greece. However, the extent of artistic perception and aesthetic appreciation has been the topic of empirical studies only recently, following the emergence of psychology as an independent field of science. The present study discusses the hypothesis that the impression created by artwork on the viewer can be predicted by examining activity of neuronal networks. In particular, we focus on neural activity evoked by abstract stimuli that matches elements of the viewers' previously learned conceptual dictionary. We show that artistic appreciation fundamentally depends on how easily the author's intent expressed in his or her artwork can be abstracted and decoded, on a neuronal level, into new or merged concept networks. More diverse intellectual and personal experiences-and their corollary neural networks-may facilitate the creation of new networks. These new networks, in turn, modulate the extent to which art can be apprehended and appreciated.

Research paper thumbnail of Resting-state EEG activity predicts frontoparietal network reconfiguration and improved attentional performance

Scientific Reports, 2020

Mounting evidence indicates that resting-state EEG activity is related to various cognitive funct... more Mounting evidence indicates that resting-state EEG activity is related to various cognitive functions. To trace physiological underpinnings of this relationship, we investigated EEG and behavioral performance of 36 healthy adults recorded at rest and during visual attention tasks: visual search and gun shooting. All measures were repeated two months later to determine stability of the results. Correlation analyses revealed that within the range of 2–45 Hz, at rest, beta-2 band power correlated with the strength of frontoparietal connectivity and behavioral performance in both sessions. Participants with lower global beta-2 resting-state power (gB2rest) showed weaker frontoparietal connectivity and greater capacity for its modifications, as indicated by changes in phase correlations of the EEG signals. At the same time shorter reaction times and improved shooting accuracy were found, in both test and retest, in participants with low gB2rest compared to higher gB2rest values. We posit...

Research paper thumbnail of EEG-neurofeedback training of beta band (12-22Hz) affects alpha and beta frequencies - A controlled study of a healthy population

Neuropsychologia, Jan 8, 2018

The frequency-function relation of various EEG bands has inspired EEG-neurofeedback procedures in... more The frequency-function relation of various EEG bands has inspired EEG-neurofeedback procedures intending to improve cognitive abilities in numerous clinical groups. In this study, we administered EEG-neurofeedback (EEG-NFB) to a healthy population to determine the efficacy of this procedure. We evaluated feedback manipulation in the beta band (12-22Hz), known to be involved in visual attention processing. Two groups of healthy adults were trained to either up- or down-regulate beta band activity, thus providing mutual control. Up-regulation training induced increases in beta and alpha band (8-12Hz) amplitudes during the first three sessions. Group-independent increases in the activity of both bands were observed in the later phase of training. EEG changes were not matched by measured behavioural indices of attention. Parallel changes in the two bands challenge the idea of frequency-specific EEG-NFB protocols and suggest their interdependence. Our study exposes the possibility (i) th...

Research paper thumbnail of Beware: Recruitment of Muscle Activity by the EEG-Neurofeedback Trainings of High Frequencies

Frontiers in Human Neuroscience, 2017

EEG-neurofeedback (NFB) became a very popular method aimed at improving cognitive and behavioral ... more EEG-neurofeedback (NFB) became a very popular method aimed at improving cognitive and behavioral performance. However, the EMG frequency spectrum overlies the higher EEG oscillations and the NFB trainings focusing on these frequencies is hindered by the problem of EMG load in the information fed back to the subjects. In such a complex signal, it is highly probable that the most controllable component will form the basis for operant conditioning. This might cause different effects in the case of various training protocols and therefore needs to be carefully assessed before designing training protocols and algorithms. In the current experiment a group of healthy adults (n = 14) was trained by professional trainers to up-regulate their beta1 (15-22 Hz) band for eight sessions. The control group (n = 18) underwent the same training regime but without rewards for increasing beta. In half of the participants trained to up-regulate beta1 band (n = 7) a systematic increase in tonic EMG activity was identified offline, implying that muscle activity became a foundation for reinforcement in the trainings. The remaining participants did not present any specific increase of the trained beta1 band amplitude. The training was perceived effective by both trainers and the trainees in all groups. These results indicate the necessity of proper control of muscle activity as a requirement for the genuine EEG-NFB training, especially in protocols that do not aim at the participants' relaxation. The specificity of the information fed back to the participants should be of highest interest to all therapists and researchers, as it might irreversibly alter the results of the training.

Research paper thumbnail of The Do's and Don'ts of Neurofeedback Training: A Review of the Controlled Studies Using Healthy Adults

Frontiers in Human Neuroscience, 2016

The goal of EEG neurofeedback (EEG-NFB) training is to induce changes in the power of targeted EE... more The goal of EEG neurofeedback (EEG-NFB) training is to induce changes in the power of targeted EEG bands to produce beneficial changes in cognitive or motor function. The effectiveness of different EEG-NFB protocols can be measured using two dependent variables: (1) changes in EEG activity and (2) behavioral changes of a targeted function (for therapeutic applications the desired changes should be long-lasting). To firmly establish a causal link between these variables and the selected protocol, similar changes should not be observed when appropriate control paradigms are used. The main objective of this review is to evaluate the evidence, reported in the scientific literature, which supports the validity of various EEG-NFB protocols. Our primary concern is to highlight the role that uncontrolled nonspecific factors can play in the results generated from EEG-NFB studies. Nonspecific factors are often ignored in EEG-NFB designs or the data are not presented, which means conclusions should be interpreted cautiously. As an outcome of this review we present a do's and don'ts list, which can be used to develop future EEG-NFB methodologies, based on the small set of experiments in which the proper control groups have excluded non-EEG-NFB related effects. We found two features which positively correlated with the expected changes in power of the trained EEG band(s): (1) protocols which focused on training a smaller number of frequency bands and (2) a bigger number of electrodes used for neurofeedback training. However, we did not find evidence in support of the positive relationship between power changes of a trained frequency band(s) and specific behavioral effects.

Research paper thumbnail of The grounds for successful neurofeedback

Research paper thumbnail of Effect of cortex inactivation on spontaneous activity of cells in perigeniculate and dorsal lateral geniculate nuclei

BMC Neuroscience, 2013

Figure 1 Effect of cortex cooling on activity of PGN and LGN cells. A. Percent of change in relat... more Figure 1 Effect of cortex cooling on activity of PGN and LGN cells. A. Percent of change in relation to situation when the cortex was active. B. Percent of significant differences (p < 0.05). IBISI-intra burst ISI, SPB-spikes per burst, BD-burst duration, ISI-mean ISI, FR-firing rate, BRbursting rate.

Research paper thumbnail of Cortical modulation of neuronal activity in the cat's lateral geniculate and perigeniculate nuclei: a modeling study

Research paper thumbnail of Decoding working memory-related information from repeated psychophysiological EEG experiments using convolutional and contrastive neural networks

Journal of Neural Engineering

Objective. Extracting reliable information from electroencephalogram (EEG) is difficult because t... more Objective. Extracting reliable information from electroencephalogram (EEG) is difficult because the low signal-to-noise ratio and significant intersubject variability seriously hinder statistical analyses. However, recent advances in explainable machine learning open a new strategy to address this problem. Approach. The current study evaluates this approach using results from the classification and decoding of electrical brain activity associated with information retention. We designed four neural network models differing in architecture, training strategies, and input representation to classify single experimental trials of a working memory task. Main results. Our best models achieved an accuracy (ACC) of 65.29 ± 0.76 and Matthews correlation coefficient of 0.288 ± 0.018, outperforming the reference model trained on the same data. The highest correlation between classification score and behavioral performance was 0.36 (p = 0.0007). Using analysis of input perturbation, we estimated...