scholarly journals Mathematical Modeling of Brain Activity under Specific Auditory Stimulation

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Marius Georgescu ◽  
Laura Haidar ◽  
Alina-Florina Serb ◽  
Daniela Puscasiu ◽  
Daniel Georgescu
Keyword(s):  
Mathematical Models ◽  
Brain Activity ◽  
Research Area ◽  
Brain Response ◽  
Mathematical Functions ◽  
Fourth Degree ◽  
Acoustic Stimuli ◽  
Minute Period ◽  
Degree Function ◽  
Before And After

Understanding the connection between different stimuli and the brain response represents a complex research area. However, the use of mathematical models for this purpose is relatively unexplored. The present study investigates the effects of three different auditory stimuli on cerebral biopotentials by means of mathematical functions. The effects of acoustic stimuli (S1, S2, and S3) on cerebral activity were evaluated by electroencephalographic (EEG) recording on 21 subjects for 20 minutes of stimulation, with a 5-minute period of silence before and after stimulation. For the construction of the mathematical models used for the study of the EEG rhythms, we used the Box-Jenkins methodology. Characteristic mathematical models were obtained for the main frequency bands and were expressed by 2 constant functions, 8 first-degree functions, a second-degree function, a fourth-degree function, 6 recursive functions, and 4 periodic functions. The values obtained for the variance estimator are low, demonstrating that the obtained models are correct. The resulting mathematical models allow us to objectively compare the EEG response to the three stimuli, both between the stimuli itself and between each stimulus and the period before stimulation.

Risk assessment models with functionally different influences on natural and technical systems

2020 ◽  
Vol 89 ◽  
pp. 8-19
Author(s):  
V. A. Minaev ◽  
◽  
N. G. Topolsky ◽  
A. O. Faddeev ◽  
R. O. Stepanov ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Differential Equations ◽  
Research Area ◽  
Practical Implementation ◽  
Model Assessment ◽  
Mathematical Functions ◽  
Effective Response ◽  
Risk Assessment Models ◽  
Technical Systems ◽  
Material Values

Introduction. The complex combination of natural and technogenic factors that lead to dangerous threats to the health and life of the population, as well as to material values, creates a need to develop special mathematical models for risk assessment in the relevant territories. Herewith it is important to take into account the significant differences between these factors. The new areas of research are models that describe natural and technogenic risks using differential equations that reflect different types of functions. The article presents the development of this research area. Goals and objectives. The goal of the article is to create a model for risk assessment in natural and technical systems (PTS), based on taking into account the influences of different natural and technogenic factors on them. Objectives include justification, construction and practical implementation of the mathematical model of risk assessment in the form of differential equations system. Methods include interpretation of the considered influences on PTS in terms of risks and assessment of the dynamic interaction of natural and technogenic factors in the form of inhomogeneous differential equations. Results and discussion. Solutions for models of assessing complex natural and technogenic risks in relation to two cases that differ in NTS are found: functionally different external natural and technogenic influences on PTS, which are understood as their type, in which the effects of both natural and technogenic factors are described by different mathematical functions. Conclusions. The first model considers parabolic (reflecting threats whose intensity gradually decreases with distance from the epicenter) and linear types of influences (reflecting sudden threats). The second model considers parabolic and hyperbolic (reflecting threats, the intensity of which decreases sharply over time) types of influences. It is concluded that it is necessary to create a special computer album of complex influences on the PTS in order to prevent "replay" of various situations and develop the most effective response to emerging dangers from the EMERCOM units and other structures. Key words: model, assessment, natural and technogenic risks, functionally different influences, counteraction, EMERCOM units.

scholarly journals Conditional Entropy: A Potential Digital Marker for Stress

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 286
Author(s):  
Soheil Keshmiri
Keyword(s):  
Resting State ◽  
Nearest Neighbor ◽  
Brain Activity ◽  
Solution Concept ◽  
Conditional Entropy ◽  
K Nearest Neighbor ◽  
Brain Response ◽  
Substantial Progress ◽  
Eeg Recordings ◽  
The Brain

Recent decades have witnessed a substantial progress in the utilization of brain activity for the identification of stress digital markers. In particular, the success of entropic measures for this purpose is very appealing, considering (1) their suitability for capturing both linear and non-linear characteristics of brain activity recordings and (2) their direct association with the brain signal variability. These findings rely on external stimuli to induce the brain stress response. On the other hand, research suggests that the use of different types of experimentally induced psychological and physical stressors could potentially yield differential impacts on the brain response to stress and therefore should be dissociated from more general patterns. The present study takes a step toward addressing this issue by introducing conditional entropy (CE) as a potential electroencephalography (EEG)-based resting-state digital marker of stress. For this purpose, we use the resting-state multi-channel EEG recordings of 20 individuals whose responses to stress-related questionnaires show significantly higher and lower level of stress. Through the application of representational similarity analysis (RSA) and K-nearest-neighbor (KNN) classification, we verify the potential that the use of CE can offer to the solution concept of finding an effective digital marker for stress.

scholarly journals Stability analysis and controller synthesis for hybrid dynamical systems

2010 ◽  
Vol 368 (1930) ◽  
pp. 4937-4960 ◽  
Author(s):  
W. P. M. H. Heemels ◽  
B. De Schutter ◽  
J. Lunze ◽  
M. Lazar
Keyword(s):  
Dynamical Systems ◽  
Mathematical Models ◽  
Hybrid Systems ◽  
Discrete Event ◽  
Research Area ◽  
Hybrid Dynamical Systems ◽  
Technological Systems ◽  
Analysis And Synthesis ◽  
Control Community ◽  
The One

Wherever continuous and discrete dynamics interact, hybrid systems arise. This is especially the case in many technological systems in which logic decision-making and embedded control actions are combined with continuous physical processes. Also for many mechanical, biological, electrical and economical systems the use of hybrid models is essential to adequately describe their behaviour. To capture the evolution of these systems, mathematical models are needed that combine in one way or another the dynamics of the continuous parts of the system with the dynamics of the logic and discrete parts. These mathematical models come in all kinds of variations, but basically consist of some form of differential or difference equations on the one hand and automata or other discrete-event models on the other hand. The collection of analysis and synthesis techniques based on these models forms the research area of hybrid systems theory, which plays an important role in the multi-disciplinary design of many technological systems that surround us. This paper presents an overview from the perspective of the control community on modelling, analysis and control design for hybrid dynamical systems and surveys the major research lines in this appealing and lively research area.

scholarly journals Daytime micro-naps in a nocturnal migrant: an EEG analysis

2008 ◽  
Vol 5 (1) ◽  
pp. 77-80 ◽  
Author(s):  
T Fuchs ◽  
D Maury ◽  
F.R Moore ◽  
V.P Bingman
Keyword(s):  
Brain Activity ◽  
Sleep Loss ◽  
Eeg Analysis ◽  
Observable Effect ◽  
Brain Response ◽  
Night Time ◽  
Avian Migration ◽  
Unihemispheric Sleep ◽  
Daytime Behaviour ◽  
Behavioural Evidence

Many species of typically diurnal songbirds experience sleep loss during the migratory seasons owing to their nocturnal migrations. However, despite substantial loss of sleep, nocturnally migrating songbirds continue to function normally with no observable effect on their behaviour. It is unclear if and how avian migrants compensate for sleep loss. Recent behavioural evidence suggests that some species may compensate for lost night-time sleep with short, uni- and bilateral ‘micro-naps’ during the day. We provide electrophysiological evidence that short episodes of sleep-like daytime behaviour (approx. 12 s) are accompanied by sleep-like changes in brain activity in an avian migrant. Furthermore, we present evidence that part of this physiological brain response manifests itself as unihemispheric sleep, a state during which one brain hemisphere is asleep while the other hemisphere remains essentially awake. Episodes of daytime sleep may represent a potent adaptation to the challenges of avian migration and offer a plausible explanation for the resilience to sleep loss in nocturnal migrants.

THE POSSIBILITY OF LINKING SPONTANEOUS AND INDUCED NEUROCOGNITIVE PLASTICITY: CAN COGNITIVE TRAINING INFLUENCE COMPENSATORY BRAIN ACTIVITY IN OLDER ADULTS? THEORETICAL AND EMPIRICAL PREMISES

2020 ◽  
Vol 18 (4) ◽  
pp. 507-523
Author(s):  
Ludmiła Zając-Lamparska
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Performance ◽  
Cognitive Training ◽  
Study Design ◽  
Successful Aging ◽  
Reference Group ◽  
Brain Activity ◽  
Before And After ◽  
Theory Of Aging

One of the most important determinants of successful aging is cognitive ability. Although cognitive decline is a well-documented phenomenon characteristic of aging, it is acknowledged that aging can also be related to cognitive neuroplasticity that allows one to compensate the decline and adapt to it. Cognitive neuroplasticity may be spontaneous or induced by external influences. An example of the former is compensatory brain activity in older adults, and the latter – improvement in cognitive functioning under the influence of cognitive training. Both the compensatory brain activity of older adults and the effectiveness of cognitive training in this age group have already been extensively studied. However, it has not yet been examined whether they can be linked. The article indicates theoretical and empirical premises for the possibility of influencing compensatory brain activity in older adults by cognitive training. In the most comprehensive way the phenomenon of compensatory brain activity in older adults is addressed by the STAC model – the Scaffolding Theory of Aging and Cognition, which also provides the theoretical grounds for the possible impact of cognitive training on compensatory brain activity. There are also empirical arguments in favour of such an impact, but they are quite limited in nature. The reason for this is the lack of research directly addressing the problem of the consistency of brain activity changes resulting from cognitive training with the assumptions of compensatory brain activity models, such as STAC. The theoretical grounds for the linkage of compensatory brain activity in older adults with the influence of cognitive training are clear. However, the analysis of the studies discussed in the article suggests that failing to embed the study design within the theoretical framework of compensatory brain activity in older adults may lead to the exclusion of factors important in drawing conclusions about this phenomenon. The following elements of the study design were identified as necessary to include: participation of young adults in the study as a reference group, usage of tasks in different difficulty levels during the measurement of brain activity and consideration of the relation between brain activity and cognitive performance, and comparison of brain activity in relation to cognitive performance before and after training in both, older and young adults.

Building the Arrow of Time… Over Time: A Sequence of Brain Activity Mapping Imagined Events in Time and Space

2018 ◽  
Vol 29 (10) ◽  
pp. 4398-4414 ◽  
Author(s):  
Baptiste Gauthier ◽  
Karin Pestke ◽  
Virginie van Wassenhove
Keyword(s):  
Brain Activity ◽  
Brain Regions ◽  
Spatial Task ◽  
Brain Response ◽  
Time And Space ◽  
Time Resolved ◽  
The Future ◽  
Spatial Dimensions ◽  
Future Events ◽  
Neural Signatures

Abstract When moving, the spatiotemporal unfolding of events is bound to our physical trajectory, and time and space become entangled in episodic memory. When imagining past or future events, or being in different geographical locations, the temporal and spatial dimensions of mental events can be independently accessed and manipulated. Using time-resolved neuroimaging, we characterized brain activity while participants ordered historical events from different mental perspectives in time (e.g., when imagining being 9 years in the future) or in space (e.g., when imagining being in Cayenne). We describe 2 neural signatures of temporal ordinality: an early brain response distinguishing whether participants were mentally in the past, the present or the future (self-projection in time), and a graded activity at event retrieval, indexing the mental distance between the representation of the self in time and the event. Neural signatures of ordinality and symbolic distances in time were distinct from those observed in the homologous spatial task: activity indicating spatial order and distances overlapped in latency in distinct brain regions. We interpret our findings as evidence that the conscious representation of time and space share algorithms (egocentric mapping, distance, and ordinality computations) but different implementations with a distinctive status for the psychological “time arrow.”

scholarly journals Humans with obesity have disordered brain responses to food images during physiological hyperglycemia

2018 ◽  
Vol 314 (5) ◽  
pp. E522-E529 ◽  
Author(s):  
Renata Belfort-DeAguiar ◽  
Dongju Seo ◽  
Cheryl Lacadie ◽  
Sarita Naik ◽  
Christian Schmidt ◽  
...  
Keyword(s):  
Brain Activity ◽  
Blood Oxygen Level Dependent ◽  
Normal Weight ◽  
Self Control ◽  
Food Cues ◽  
Brain Response ◽  
Glucose Levels ◽  
Hyperglycemic Clamp ◽  
Brain Responses ◽  
Food Images

Blood glucose levels influence brain regulation of food intake. This study assessed the effect of mild physiological hyperglycemia on brain response to food cues in individuals with obesity (OB) versus normal weight individuals (NW). Brain responses in 10 OB and 10 NW nondiabetic healthy adults [body mass index: 34 (3) vs. 23 (2) kg/m2, means (SD), P < 0.0001] were measured with functional MRI (blood oxygen level-dependent contrast) in combination with a two-step normoglycemic-hyperglycemic clamp. Participants were shown food and nonfood images during normoglycemia (~95 mg/dl) and hyperglycemia (~130 mg/dl). Plasma glucose levels were comparable in both groups during the two-step clamp ( P = not significant). Insulin and leptin levels were higher in the OB group compared with NW, whereas ghrelin levels were lower (all P < 0.05). During hyperglycemia, insula activity showed a group-by-glucose level effect. When compared with normoglycemia, hyperglycemia resulted in decreased activity in the hypothalamus and putamen in response to food images ( P < 0.001) in the NW group, whereas the OB group exhibited increased activity in insula, putamen, and anterior and dorsolateral prefrontal cortex (aPFC/dlPFC; P < 0.001). These data suggest that OB, compared with NW, appears to have disruption of brain responses to food cues during hyperglycemia, with reduced insula response in NW but increased insula response in OB, an area involved in food perception and interoception. In a post hoc analysis, brain activity in obesity appears to be associated with dysregulated motivation (striatum) and inappropriate self-control (aPFC/dlPFC) to food cues during hyperglycemia. Hyperstimulation for food and insensitivity to internal homeostatic signals may favor food consumption to possibly play a role in the pathogenesis of obesity.

scholarly journals Effects of Virtual Reality Immersion and Audiovisual Distraction Techniques for Patients with Pruritus

2009 ◽  
Vol 14 (4) ◽  
pp. 283-286 ◽  
Author(s):  
Vera Leibovici ◽  
Florella Magora ◽  
Sarale Cohen ◽  
Arieh Ingber
Keyword(s):  
Virtual Reality ◽  
Atopic Dermatitis ◽  
Psoriasis Vulgaris ◽  
Brain Activity ◽  
Computer Game ◽  
Functional Magnetic Resonance ◽  
Before And After ◽  
Chronic Pruritus ◽  
Subjective Reports ◽  
Advanced Computer

BACKGROUND: Virtual reality immersion (VRI), an advanced computer-generated technique, decreased subjective reports of pain in experimental and procedural medical therapies. Furthermore, VRI significantly reduced pain-related brain activity as measured by functional magnetic resonance imaging. Resemblance between anatomical and neuroendocrine pathways of pain and pruritus may prove VRI to be a suitable adjunct for basic and clinical studies of the complex aspects of pruritus.OBJECTIVES: To compare effects of VRI with audiovisual distraction (AVD) techniques for attenuation of pruritus in patients with atopic dermatitis and psoriasis vulgaris.METHODS: Twenty-four patients suffering from chronic pruritus – 16 due to atopic dermatitis and eight due to psoriasis vulgaris – were randomly assigned to play an interactive computer game using a special visor or a computer screen. Pruritus intensity was self-rated before, during and 10 min after exposure using a visual analogue scale ranging from 0 to 10. The interviewer rated observed scratching on a three-point scale during each distraction program.RESULTS: Student’sttests were significant for reduction of pruritus intensity before and during VRI and AVD (P=0.0002 and P=0.01, respectively) and were significant only between ratings before and after VRI (P=0.017). Scratching was mostly absent or mild during both programs.CONCLUSIONS: VRI and AVD techniques demonstrated the ability to diminish itching sensations temporarily. Further studies on the immediate and late effects of interactive computer distraction techniques to interrupt itching episodes will open potential paths for future pruritus research.

scholarly journals Eye contact during joint attention with a humanoid robot modulates oscillatory brain activity

2021 ◽  
Author(s):  
Kyveli Kompatsiari ◽  
Francesco Bossi ◽  
Agnieszka Wykowska
Keyword(s):  
Joint Attention ◽  
Humanoid Robot ◽  
Brain Activity ◽  
Eye Contact ◽  
Mu Rhythm ◽  
Brain Response ◽  
Functional Roles ◽  
Gaze Cueing ◽  
Human Partner ◽  
Oscillatory Brain Activity

Eye contact established by a human partner has been shown to affect various cognitive processes of the receiver. However, little is known about humans’ responses to eye contact established by a humanoid robot. Here, we aimed at examining humans’ oscillatory brain response to eye contact with a humanoid robot. Eye contact (or lack thereof) was embedded in a gaze cueing task and preceded the phase of gaze-related attentional orienting. In addition to examining the effect of eye contact on the recipient, we also tested its impact on gaze cueing effects. Results showed that participants rated eye contact as more engaging and responded with higher desynchronization of alpha-band activity in left fronto-central and central electrode clusters when the robot established eye contact with them, compared to no eye contact condition. However, eye contact did not modulate gaze cueing effects. The results are interpreted in terms of the functional roles involved in alpha central rhythms (potentially interpretable also as mu rhythm), including joint attention and engagement in social interaction.

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