Grzegorz Marcin Wójcik

Grzegorz Marcin Wójcik
Maria Curie-Sklodowska University in Lublin · Institute of Computer Science

Dr. habil.

About

65
Publications
15,582
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Introduction
Dr. habil. Grzegorz Marcin Wójcik specialises in the field of computational neuroscience and quantitative EEG, holds the doctor’s degree in Computer Physics and habilitation in Biocybernetics and Biomedical Engineering. The Associate Professor and the Head of the Department of Neuroinformatics and Biomedical Engineering in Maria Curie-Sklodowska University in Lublin. Head of the Department of Intelligent Systems and Data Science in Polish-Japanese Academy of Information Technology in Warsaw.

Publications

Publications (65)
Article
Full-text available
Understanding how humans evaluate credibility is an important scientific question in the era of fake news. Source credibility is among the most important aspects of credibility evaluations. One of the most direct ways to understand source credibility is to use measurements of brain activity of humans who make credibility evaluations. This article r...
Article
Full-text available
Understanding how humans evaluate credibility is an important scientific question in the era of fake news. Message credibility is among crucial aspects of credibility evaluations. One of the most direct ways to understand message credibility is to use measurements of brain activity of humans performing credibility evaluations. Nevertheless, message...
Article
Full-text available
Behavioral and neuroimaging studies show that people trust and collaborate with others based on a quick assessment of the facial appearance. Based on the morphological characteristics of the face, i.e., features, shape, or color, it is possible to determine health, attractiveness, trust, and some personality traits. The study attempts to indicate t...
Article
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In the Internet era, proliferation of fake news can cause serious social and individual consequences. Little is known about why Web users believe or disbelieve fake news. This article aims to make progress in this area by studying brain activity during credibility evaluation. We conducted an experiment that mimics a condition when fake news are eva...
Article
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Using the large database of STR (Short Tandem Repeat) DNA results of southeastern Polish population were validated with regard to the correctness of data by testing the interdependence of loci and the Hardy-Weinberg hypothesis. It turned that the data was correct so that this topic was given up. Furthermore, dividing this population according to th...
Article
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Objectives The most common technique of determining biological paternity or another relationship among people are the investigations of DNA polymorphism called Fingerprinting DNA. The key concept of these investigations is the statistical analysis, which leads to obtain the likelihood ratio (LR), sometimes called the paternity index. Methods Among...
Article
Full-text available
Objectives The electroencephalographic signal is largely exposed to external disturbances. Therefore, an important element of its processing is its thorough cleaning. Methods One of the common methods of signal improvement is the independent component analysis (ICA). However, it is a computationally expensive algorithm, hence methods are needed to...
Article
Full-text available
Understanding how humans evaluate credibility is an important scientific question in the era of fake news. Source credibility is among the most important aspects of credibility evaluations. One of the most direct ways to understand source credibility is to use measurements of brain activity of humans performing credibility evaluations. Nevertheless...
Chapter
Full-text available
Understanding how humans evaluate credibility is an important scientific question in the era of fake news. Source credibility is among the most important aspects of credibility evaluations. One of the most direct ways to understand source credibility is to use measurements of brain activity of humans who make credibility evaluations. Nevertheless,...
Chapter
Full-text available
In the Internet era, understanding why humans find messages from unknown receivers credible (such as fake news) is an important research topic. Message credibility is an important theoretical aspect of credibility evaluation that relies only on message contents and design. For the first time in the field, we study message credibility by directly me...
Article
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The electroencephalographic activity of particular brain areas during the decision making process is still little known. This paper presents results of experiments on the group of 30 patients with a wide range of psychiatric disorders and 41 members of the control group. All subjects were performing the Iowa Gambling Task that is often used for dec...
Article
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The Event-Related Potentials were investigated on a group of 70 participants using the dense array electroencephalographic amplifier with photogrammetry geodesic station. The source localisation was computed for each participant. The activity of brodmann areas (BAs) involved in the brain cortical activity of each participant was measured. Then the...
Article
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The purpose of the present study was to identify the effect of acoustic neurofeedback on brain activity during consecutive stages of mental rotation of 3D objects. Given the fact that the process of mental rotation of objects is associated with desynchronisation of beta rhythm (beta ERD), it was expected that suppression in this band would be great...
Article
Full-text available
Brain-Computer Interfaces (BCI) constitute an alternative channel of communication between humans and environment. There are a number of different technologies which enable the recording of brain activity. One of these is electroencephalography (EEG). The most common EEG methods include interfaces whose operation is based on changes in the activity...
Article
Full-text available
There are still no good quantitative methods to be applied in psychiatric diagnosis. The interview is still the main and most important tool in the psychiatrist work. This paper presents the results of electroencephalographic research with the subjects of a group of 30 patients with psychiatric disorders compared to the control group of healthy vol...
Conference Paper
Full-text available
This paper presents the basic research station for the testing of neurofeedback phenomena. The most important part of the system is a hardware module driving a pair of tricolor goggles. This part of the system covers the full 24-bit (RGB) color palette. The goggles used by us eliminate external stimuli and significantly distinguish our station from...
Conference Paper
Full-text available
In this paper we present the experimental set-up that was constructed to study Steady State Visually Evoked Potentials (SSVEP). It is based on the DSM-51 unit that works as a hard real-time controller, connected with goggles containing blinking tricolor (RGB) LED diodes. The EEG system used in our experiments was Mindset-1000 with 16 channels, 16 b...
Article
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It was previously reported, that temperature may significantly influence neural dynamics on different levels of brain modelling. Due to this fact, while creating the model in computational neuroscience we would like to make it scalable for wide-range of various brain temperatures. However currently, because of a lack of experimental data and an abs...
Article
Full-text available
The interview is still the main and most important tool in psychiatrist's work. The neuroimaging methods such as CT or MRI are widely used in other fields of medicine, for instance neurology. However, psychiatry lacks effective quantitative methods to support of diagnosis. A novel neuroinformatic approach to help clinical patients by means of elect...
Chapter
Full-text available
Independent Component Analysis (ICA) is known as a signal cleaning method that allows the artifacts to be extracted and subsequently eliminated. It is especially essential while processing the EEG data. However, this is a time-consuming algorithm especially if we deal with a high-dimensional data and take care about the calculation accuracy. One of...
Article
Full-text available
More profound understanding of the relationship between the burnout and the limbic system function can provide better insight into brain structures associated with the burnout syndrome. The objective of this review is to explore all evidence of limbic brain structures associated with the burnout syndrome. In total, 13 studies were selected. Four of...
Article
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During processing the EEG signal, the methods of cleaning it from artifacts play an important role. One of the most commonly used methods is ICA (independent component analysis) [1-3]. However, algorithms of this type are computationally expensive. Known implementations of ICA type algorithms rarely include the possibility of parallel computing and...
Article
Full-text available
Component analysis is one of the most important methods used for electroencephalographic (EEG) signal decomposition, and the so-called independent component analysis (ICA) is commonly used. The main function of the ICA algorithm is to find a linear representation of non-Gaussian data whose elements are statistically independent or at least as indep...
Article
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The paper describes an application that allows to use a humanoid robot as a stutterer’s assistant and therapist. Auditory and visual feedback has been used in the therapy with a humanoid robot. For this purpose, the common method of “echo” was modified. The modification is that the speaker hears delayed speech sounds uttered by the robot. The sound...
Article
Full-text available
Separation ability is one of two most important properties of Liquid State Machines used in the Liquid Computing theory. To measure the so-called distance of states that Liquid State Machine can exist in - different norms and metrics can be applied. Till now we have used the Euclidean distance to tell the distance of states representing different s...
Article
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Electroencephalography (EEG) has become more popular, and as a result, the market grows with new EEG products. The new EEG solutions offer higher mobility, easier application, and lower price. One of such devices that recently became popular is Emotiv EEG. It has been already tested in various applications concerning brain-computer interfaces, neur...
Article
Full-text available
Steady State Visually Evoked Potentials have been known for several decades and they appear in the primary visual cortex of brain as a result of light stimulation of the sense of sight. In this article a simple method for electroencephalographic data acquisition is presented. The system is based on the DSM-51 unit connected to goggles with blinking...
Article
Full-text available
Liquid Computing Theory is a proposal of modelling the behaviour of neural microcircuits. It focuses on creating a group of neurons, known as a liquid layer, responsible for preprocessing of the signal that is being analysed. Specific information is achieved by the readout layers, task oriented groups of neurons, taught to extract particular inform...
Article
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In this paper the research on a person declaring synesthetic abilities will be presented. According to the current state of knowledge synesthesia activates additional cortical fields in the brain which can be found in the EEG. The research was conducted using an EGI-EEG system (Electrical Geodesic Inc., Eugene, Oregon, USA) with the GeoSource softw...
Article
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Despite the quick development of medicine and associated medical technology, there are still many patients with very severe neurological deficits who need far more sophisticated solutions, such as brain computer interfaces (BCIs). Our research aims at becoming familiar with BCI technology and the assessment of the possibilities of selected subjects...
Article
Full-text available
A diversity of symptoms in autism dictates a broad definition of Autism Spectrum of Disorders (ASD). Each year, the percentage of children diagnosed with ASD is growing. One common diagnostic feature in individuals with ASD is the tendency to exhibit atypical simple cyclic movements. The motor brain activity seems to generate a periodic attractor s...
Article
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This paper focuses on finding the most efficinet way of performing local and remote computations with web application based on ActionScript language. Tests involve comparsion of several scenarions which uses pure ActionScript, ActionScript with Alchemy project and ActionScript connecting with C application over AMF protocol and with FileReference c...
Article
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Every year the prevalence of Autism Spectrum of Disorders (ASD) is rising. Is there a unifying mechanism of various ASD cases at the genetic, molecular, cellular or systems level? The hypothesis advanced in this paper is focused on neural dysfunctions that lead to problems with attention in autistic people. Simulations of attractor neural networks...
Article
Full-text available
Two and three dimensional models of rat barrel and somatosensory cortex were simulated. Hoddgkin–Huxley and Leaky-Integrate-and-Fire neurons were used to the construction of the networks in GENESIS and PCSIM environments. The dynamics of both models was analysed. Self-organising criticality phenomena were found. Profound investigations of this beha...
Article
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The model of mammalian cortical hypercolumn was simulated using liquid state machines built of simple Hodgkin–Huxley neurons. The influence of cell electrical parameters on the system dynamics was investigated. The systematic analysis of the hypercolumn separation ability in the function of time constants, cell membrane capacitance, resistance, Hod...
Conference Paper
Full-text available
Frequency of diagnoses of diseases, which belong to Autism Spectrum of Disorders (ASD) increases with each year. The question is: is there a unifying mechanism at molecular, cellular or systems level? In the paper we present our point of view to problem of attention in autistic people. Simulations using neural network model with attractor analysis...
Article
Full-text available
Large and sudden changes in pitch or loudness occur statistically less frequently than gradual fluctuations, which means that natural sounds typically exhibit 1/f spectra. Experiments conducted on human subjects showed that listeners indeed prefer 1/f distributed melodies to melodies with faster or slower dynamics. It was recently demonstrated by u...
Article
This article discusses the first successful phase of our work on the construction of a complete modular research station for EEG signal acquisition and analysis performed in real-time mode and in a way that meets our needs. Our intentions were presented in [1].
Article
Mixed reality techniques are presented. Implementation and application of CAMSHIFT algorithm is discussed to some extent. In the initial stage of the research the technology of real object's edge detection and geometrical figures' representation in the virtual scene has been worked out.
Conference Paper
Full-text available
The properties of separation ability and computational efficiency of liquid state machines depend on the neural model employed and on the connection density in the liquid column. A simple model of part of mammalians visual system consisting of one hypercolumn was examined. Such a system was stimulated by two different input patterns, and the Euclid...
Conference Paper
Full-text available
This paper presents an approach to facial expression recognition based on the theory of liquid computing. Up to date, no emotion recognition systems based on spiking neural networks exist, and our work is the first attempt in this direction. We investigated the pattern recognition ability of Liquid State Machines based on various neural models, suc...
Conference Paper
Full-text available
The model of the part of the rat somatosensory cortex was examined. Large network of Hodgkin-Huxley neurons was simulated and the modular architecture of this structure divided into layers and sub-regions was implemented. High degree of complexity required effective parallelisation of the simulation. In this article the results of the parallel neur...
Conference Paper
Full-text available
For this study systems of Hodgkin Huxley neural networks consisting of about 16 thousands of cells are examined. We base on Liquid Computing theory. The separation ability of the system of Liquid State Machines depends on the choice of time constants characterising particular neurons. The main objective of research presented in this article is to i...
Article
Full-text available
Mammalian brains consisting of up to 10 11 neurons belong to group of the most complex systems in the Universe. For years they have been one of the hardest objects of simulation. There are many different approaches to modelling of neurons, but one of the most biologically correct is Hodgkin-Huxley (HH) model. Simulations that require solving a larg...
Article
The idea of electric brain activity acquisition for LINUX OS is presented. So far the only available software has been that for MS-Windows. The general concept of the modular data acquisition system as independent of its particular parts as possible and based on the LINUX pipe system will be discussed to some extent. Adapting the hardware to open s...
Conference Paper
Full-text available
Large Hodgkin-Huxley (HH) neural networks were examined and the structures discussed in this article simulated a part of the rat somatosensory cortex. We used a modular architecture of the network divided into layers and sub-regions. Because of a high degree of complexity effective parallelisation of algorithms was required. The results of parallel...
Article
Full-text available
Large artificial Hodgkin–Huxley neural networks are examined. The structures discussed in this article simulate a part of the cortex of the mammalian visual system. We use a modular architecture of the cortex divided into sub-regions. Results of parallel simulations based on the liquid computing theory are presented in some detail. Separation abili...
Conference Paper
Full-text available
Large artificial Hodgkin-Huxley neural networks are examined. The structures discussed in this article simulate the cortex of the mammalian visual system. We use a modular architecture of the cortex divided into sub-regions. Results of parallel simulations based on the liquid computing theory are presented in some detail. Separation ability of grou...
Conference Paper
Full-text available
Large artificial neural networks are examined. The structures discussed in this article simulate the cortex of the mammalian visual system. We use a modular architecture of the cortex divided into sub-regions. The modular structure of visual system is appropriate task for cluster computations. Our models consist of 16 to 65 thousands Hodgkin-Huxley...
Conference Paper
Full-text available
Large artificial neural networks are examined. Structures discussed in this article simulate the cortex of mammalian visual system and its dynamics. Simulations of thousands of Hodgkin-Huxley neurons always require high computational power. Discussion of such networks parallelisation is presented in some detail. Analysis of simulation time, algorit...
Article
Neural networks built of Hodgkin–Huxley neurons were examined. The structure and behavior of these nets was intended to be similar to liquid state machines. They could effectively process different input signals (i.e. geometrical patterns shown to artificial eye). The analysis of output responses was performed in two ways: by means of artificial ne...
Article
Full-text available
Neural networks built of Hodgkin-Huxley neurons were examined. These structures behaved like Liquid State Machines (LSM). They could effectively process different input signals (i.e., Morse alphabet) into precisely defined output. It is also shown that there is a possibility of logical gates creation with use of Hodgkin-Huxley neurons and simple LS...
Article
Full-text available
Neural networks built of Hodgkin-Huxley neurons are examined. Such structures behave like Liquid State Machines. They can effectively process geometrical patterns shown to "artificial retina" into precisely defined output. The analysis of output responses is performed in two ways: by means of Artificial Neural Network and by calculating information...
Article
Full-text available
We examine a simple model of mammalian visual system. This structure is simulated by means of several hundred Hodgkin-Huxley neurons. We investigate signal processing properties of the model. Some methods taken from informational theory are applied to the analysis of Primary Visual Cortex' dynamics. Discussion of efficiency of such methods in two d...