- Artículo de Publicación PeriódicaEPOC Emotiv EEG Basics(2022-10)This document provides some basic guidance to start working with the EPOC Emotiv neuroheadset device and describes how to use it to perform basic Brain-Computer Interface (BCI) research. A brief tutorial on how to set up the device, from its electrophysiological point of view, as well as a description and practical code to perform some basic analysis, is explained. A basic experiment is introduced to detect one of the oldest and, indeed, quite still valuable electrophysiological correlate, visual occipital alpha waves, or Berger Rhythm. An additional experiment is expounded where the power spectrum of alpha waves is reduced when a subject is affected by background cognitive disturbances. This document also briefs about the extraction of information by using the EPOC Emotiv library and also with python Emokit package. This report presents a basic guide on how to use EEGLAB + MATLAB, as well as python stack to perform the neurophysiological analysis. Finally, a basic analysis on different feature extraction and classification methods is provided.
- Artículo de Publicación PeriódicaTowards an experimental control of neural activity: The Wilson-Cowan model(IFAC-PapersOnLine, 2022)The prospect of modifying neural activity in a principled way, could facilitate the understanding of brain functions and the development of medical treatments. To predict the dynamics that underlie the different brain activities, several neurobiological models have been proposed, either focusing on individual cells or whole populations. In this context, control systems are a powerful tool to provide a correct articulation between inputs, i.e. neural stimuli, and observables, i.e. system outcomes. Based on well-established neurobiological hypotheses, this study presents a control framework to regulate a neural-mass activity, with potential uses for pattern tracking, such as, rhythm evoking and phase synchronisation. Being these mechanisms closely connected with real brain computations, this study is carried out using a meaningful perspective in terms of biological interpretation. To this end, the Wilson-Cowan model is used, where the input stimuli is elicited through light signals applied to genetically modified neurons that express light-gated actuators. Thus, this study states a crucial proof of concept towards a future experimental application of the control framework for neurobiological systems.
- Artículo de Publicación PeriódicaSpontaneous and induced out-of-body experiences during sleep paralysis: Emotions, “AURA” recognition, and clinical implications(2022)"Sleep paralysis is characterized by the incapacity to perform voluntary movements during sleep/wake transitions, and could bring great discomfort. During sleep paraly sis, out-of-body experiences can occur. Out-of-body experiences refers to the sensation of being outside of the physical body and perceiving the world from this outside perspective; however, they are pleasant in comparison with other sleep paralysis hallucinations. Lucid dreams are dreams in which a subject becomes aware of being dreaming while the dream occurs. Here, we designed an online survey to study the predominant and specific emotions during sleep paralysis and/or out-of-body experience events as well as the somatosensory perceptions that preceded their occurrence. The sample (N = 329) was divided into experimental groups depending on the presence/absence of out-of-body experiences, capacity to induce (or not) out-of body experiences, and perception/no-perception of the sleep paralysis. We showed that more positive emotions were associated with out-of-body experiences and more negative emotions were associated with sleep paralysis episodes, and for those who claim the ability to induce out-of-body experiences, positive emotions were more frequent in their episodes. We found that subjects perceived auditory, tactile and visual sensations before sleep paralysis episodes, and we proposed that these could be an “aura” of sleep paralysis. Furthermore, subjects that had out-of-body experiences but had never felt the sleep paralysis, perceived tactile and visual sensations to the same extent as subjects with out-of-body experiences that felt the sleep paralysis." Therefore, we proposed that the “aura” recognition could be used under controlled conditions for out-of-body experiences induction in patients with sleep paralysis to diminish the negative symptoms associated with sleep paralysis episodes
- Artículo de Publicación PeriódicaDynamical models in neuroscience from a closed-loop control perspective(2022-01-28)"Modifying neural activity is a substantial goal in neuroscience that facilitates the understanding of brain functions and the development of medical therapies. Neurobiological models play an essential role, contributing to the understanding of the underlying brain dynamics. In this context, control systems represent a fundamental tool to provide a correct articulation between model stimulus (system inputs) and outcomes (system outputs). However, throughout the literature there is a lack of discussions on neurobiological models, from the formal control perspective. In general, existing control proposals applied to this family of systems, are developed empirically, without theoretical and rigorous framework. Thus, the existing control solutions, present clear and significant limitations. The focus of this work is to survey dynamical neurobiological models that could serve for closed-loop control schemes or for simulation analysis. Consequently, this paper provides a comprehensive guide to discuss and analyze control oriented neurobiological models. It also provides a potential framework to adequately tackle control problems that could modify the behavior of single neurons or networks. Thus, this study constitutes a key element in the upcoming discussions and studies regarding control methodologies applied to neurobiological systems, to extend the present research and understanding horizon for this field."
- Artículo de Publicación PeriódicaClassification based on dynamic mode decomposition applied to brain recognition of context(2021-09)"Local Field Potentials (LFPs) are easy to access electrical signals of the brain that represent the summation in the extracellular space, of currents originated within the neurons. As such, LFPs could contain infor mation about ongoing computations in neuronal circuits and could potentially be used to design brain machine interface algorithms. However how brain computations could be decoded from LFPs is not clear. Within this context, a methodology for signal classification is proposed in this study, particularly based on the Dynamic Mode Decomposition method, in conjunction with binary clustering routines based on supervised learning. Note that, although the classification methodology is presented here in the context of a biological problem, it can be applied to a broad range of applications. Then, as a case-study, the proposed method is validated with the classification of LFP-based brain cognitive states. All the analysis, signals, and results shown in this study consider real data measured in the hippocampus, in rats perform ing exploration tasks. Consequently, it is shown that, using the measured LFP, the method infers which context was the animal exploring. Thus, evidence on the spatial codification in LFP signals is consequently provided, which still is an open question in neuroscience."