STATISTICAL MEMORY OF MEG SIGNALS AT PHOTOSENSITIVE EPILEPSY

2008 ◽  
Vol 18 (09) ◽  
pp. 2799-2805 ◽  
Author(s):  
R. M. YULMETYEV ◽  
E. V. KHUSAENOVA ◽  
D. G. YULMETYEVA ◽  
P. HÄNGGI ◽  
S. SHIMOJO ◽  
...  
Keyword(s):  
Human Brain ◽  
Chaotic Behavior ◽  
Brain Functioning ◽  
Dynamical Characteristics ◽  
Control Subjects ◽  
Brain Responses ◽  
Photosensitive Epilepsy ◽  
Different Color ◽  
Color Combinations

Here we discuss the remarkable role of the statistical memory effects in the human brain functioning at photosensitive epilepsy (PSE). We have analyzed three independent statistical memory quantifiers for the magnetoencephalographic (MEG) signals. These quantifiers reflect the dynamical characteristics of neuromagnetic brain responses to a flickering stimulus of different color combinations. Results for a group of control subjects are contrasted with those from a patient with PSE. The emergence of the strong memory and the transition to a regular and robust regime of chaotic behavior of the signals in separate areas is characteristic for a patient with PSE versus a healthy brain.

scholarly journals The Right Hemisphere Is Responsible for the Greatest Differences in Human Brain Response to High-Arousing Emotional versus Neutral Stimuli: A MEG Study

2021 ◽  
Vol 11 (8) ◽  
pp. 960
Author(s):  
Mina Kheirkhah ◽  
Philipp Baumbach ◽  
Lutz Leistritz ◽  
Otto W. Witte ◽  
Martin Walter ◽  
...  
Keyword(s):  
Human Brain ◽  
Right Hemisphere ◽  
Emotional Stimuli ◽  
Brain Response ◽  
Whole Brain ◽  
Brain Responses ◽  
Cortical Regions ◽  
The Right ◽  
Healthy Participants

Studies investigating human brain response to emotional stimuli—particularly high-arousing versus neutral stimuli—have obtained inconsistent results. The present study was the first to combine magnetoencephalography (MEG) with the bootstrapping method to examine the whole brain and identify the cortical regions involved in this differential response. Seventeen healthy participants (11 females, aged 19 to 33 years; mean age, 26.9 years) were presented with high-arousing emotional (pleasant and unpleasant) and neutral pictures, and their brain responses were measured using MEG. When random resampling bootstrapping was performed for each participant, the greatest differences between high-arousing emotional and neutral stimuli during M300 (270–320 ms) were found to occur in the right temporo-parietal region. This finding was observed in response to both pleasant and unpleasant stimuli. The results, which may be more robust than previous studies because of bootstrapping and examination of the whole brain, reinforce the essential role of the right hemisphere in emotion processing.

NONLINEAR DYNAMICS OF EVOKED NEUROMAGNETIC RESPONSES SIGNIFIES POTENTIAL DEFENSIVE MECHANISMS AGAINST PHOTOSENSITIVITY

2004 ◽  
Vol 14 (08) ◽  
pp. 2701-2720 ◽  
Author(s):  
JOYDEEP BHATTACHARYA ◽  
KATSUMI WATANABE ◽  
SHINSUKE SHIMOJO
Keyword(s):  
Nonlinear Dynamical System ◽  
Stimulus Frequency ◽  
Dynamical System Theory ◽  
Healthy Human ◽  
Nonlinear Dynamical ◽  
Time Frequency ◽  
Control Subjects ◽  
Photosensitive Epilepsy ◽  
Different Color ◽  
Measuring Signal

We investigated the dynamical characteristics of neuromagnetic responses by recording magnetoencephalographic (MEG) signals to equiluminant flickering stimulus of different color combinations from a group of control subjects, and from a patient with photosensitive epilepsy. By wavelet based time-frequency analysis, we showed that two distinct neuromagentic responses corresponding to stimulus frequency and its time delayed first harmonic were found in control subjects, whereas no harmonic response was obtained for the patient. We applied a battery of methods (sample entropy measuring signal complexity and index of smoothness measuring determinism) based on nonlinear dynamical system theory in conjunction with bootstrapping surrogate analysis. The results suggested that a significant nonlinear structure was evident in the MEG signals for control subjects, whereas nonlinearity was not detected for the patient. In addition, the couplings between distant cortical regions were found to be greater for control subjects. The important role of combinational chromatic sensitivity in sustained cortical excitation was also confirmed. These findings lead to the hypothesis that the healthy human brain is most likely equipped with significantly nonlinear neuronal processing reflecting an inherent mechanism defending against hyper-excitation to chromatic flickering stimulus, and such nonlinear mechanism is likely to be impaired for a patient with photosensitive epilepsy.

Role of structural plasticity in the human brain for multisensory compensation following unilateral peripheral vestibular lesion

2008 ◽  
Vol 35 (S 01) ◽  
Author(s):  
C Helmchen ◽  
J Klinkenstein ◽  
T Sander ◽  
J Gliemroth ◽  
B Machner ◽  
...  
Keyword(s):  
Human Brain ◽  
Structural Plasticity ◽  
Vestibular Lesion

scholarly journals EEG Correlates of Old/New Discrimination Performance Involving Abstract Figures and Non-Words

2021 ◽  
Vol 11 (6) ◽  
pp. 719
Author(s):  
Monika Toth ◽  
Anke Sambeth ◽  
Arjan Blokland
Keyword(s):  
Recognition Memory ◽  
Current Knowledge ◽  
Discrimination Performance ◽  
Correct Identification ◽  
Memory Strength ◽  
Verbal Stimuli ◽  
Brain Responses ◽  
Three Phase ◽  
New Item

The processing of pre-experimentally unfamiliar stimuli such as abstract figures and non-words is poorly understood. Here, we considered the role of memory strength in the discrimination process of such stimuli using a three-phase old/new recognition memory paradigm. Memory strength was manipulated as a function of the levels of processing (deep vs. shallow) and repetition. Behavioral results were matched to brain responses using EEG. We found that correct identification of the new abstract figures and non-words was superior to old item recognition when they were merely studied without repetition, but not when they were semantically processed or drawn. EEG results indicated that successful new item identification was marked by a combination of the absence of familiarity (N400) and recollection (P600) for the studied figures. For both the abstract figures and the non-words, the parietal P600 was found to differentiate between the old and new items (late old/new effects). The present study extends current knowledge on the processing of pre-experimentally unfamiliar figurative and verbal stimuli by showing that their discrimination depends on experimentally induced memory strength and that the underlying brain processes differ. Nevertheless, the P600, similar to pre-experimentally familiar figures and words, likely reflects improved recognition memory of meaningless pictorial and verbal items.

The human brain: Chairman’s introduction

1981 ◽  
Vol 292 (1057) ◽  
pp. 151-153
Keyword(s):  
Human Brain ◽  
Cultural Evolution ◽  
Positive Feedback ◽  
Time Scale ◽  
Biological Evolution ◽  
Internal Models ◽  
Adaptive Behaviour ◽  
Myelin Sheaths ◽  
The Brain

Much has been said at the symposium about the pre-eminent role of the brain in the continuing emergence of man. Tobias has spoken of its explosive enlargement during the last 1 Ma, and how much of its enlargement in individual ontogeny is postnatal. We are born before our brains are fully grown and ‘wired up ’. During our long adolescence we build up internal models of the outside world and of the relations of parts of our bodies to it and to one another. Neurons that are present at birth spread their dendrites and project axons which acquire their myelin sheaths, and establish innumerable contacts with other neurons, over the years. New connections are formed; genetically endowed ones are stamped in or blanked off. People born without arms may grow up to use their toes in skills that are normally manual. Tobias, Darlington and others have stressed the enormous survival value of adaptive behaviour and the ‘positive feedback’ relation between biological and cultural evolution. The latter, the unique product of the unprecedentedly rapid biological evolution of big brains, advances on a time scale unknown to biological evolution.

The growth hormone axis and cognition: empirical results and integrated theory derived from giant transgenic mice

1999 ◽  
Vol 77 (12) ◽  
pp. 1874-1890 ◽  
Author(s):  
C D Rollo ◽  
C V Ko ◽  
JG A Tyerman ◽  
L J Kajiura
Keyword(s):  
Growth Hormone ◽  
Accelerated Aging ◽  
Error Rates ◽  
Transgenic Rat ◽  
Brain Functioning ◽  
Neuroendocrine Mechanisms ◽  
System Functioning ◽  
Plasma Gh ◽  
Enhanced Learning

Sleep is required for the consolidation of memory for complex tasks, and elements of the growth-hormone (GH) axis may regulate sleep. The GH axis also up-regulates protein synthesis, which is required for memory consolidation. Transgenic rat GH mice (TRGHM) express plasma GH at levels 100-300 times normal and sleep 3.4 h longer (30%) than their normal siblings. Consequently, we hypothesized that they might show superior ability to learn a complex task (8-choice radial maze); 47% of the TRGHM learned the task before any normal mice. All 17 TRGHM learned the task, but 33% of the 18 normal mice learned little. TRGHM learned the task significantly faster than normal mice (p < 0.05) and made half as many errors in doing so, even when the normal nonlearners were excluded from the analysis. Whereas normal mice expressed a linear learning curve, TRGHM showed exponentially declining error rates. The contribution of the GH axis to cognition is conspicuously sparse in literature syntheses of knowledge concerning neuroendocrine mechanisms of learning and memory. This paper synthesizes the crucial role of major components of the GH axis in brain functioning into a holistic framework, integrating learning, sleep, free radicals, aging, and neurodegenerative diseases. TRGHM show both enhanced learning in youth and accelerated aging. Thus, they may provide a powerful new probe for use in gaining an understanding of aspects of central nervous system functioning, which is highly relevant to human health.

Pertinence of Predictive Models as Regards the Behavior of Observed Biological and Artificial Phenomena

2021 ◽  
Vol 8 (3) ◽  
pp. 189-200
Author(s):  
Adel Razek
Keyword(s):  
Link Prediction ◽  
Clinical Observation ◽  
Mutant Virus ◽  
Brain Functioning ◽  
Bayesian Brain ◽  
Digital Twins ◽  
Brain Theory ◽  
Observation Protocol ◽  
Knowledge Uncertainty

In this assessment, we have made an effort of synthesis on the role of theoretical and observational investigations in the analysis of the concepts and functioning of different natural biological and artificial phenomena. In this context, we pursued the objective of examining published works relating to the behavioral prediction of phenomena associated with its observation. We have examined examples from the literature concerning phenomena with known behaviors that associated to knowledge uncertainty as well as cases concerning phenomena with unknown and changing random behaviors linked to random uncertainty. The concerned cases are relative to brain functioning in neuroscience, modern smart industrial devices, and health care predictive endemic protocols. As predictive modeling is very concerned by the problematics relative to uncertainties that depend on the degree of matching in the link prediction-observation, we investigated first how to improve the model to match better the observation. Thus, we considered the case when the observed behavior and its model are contrasting, that implies the development of revised or amended models. Then we studied the case concerning the practice of modeling for the prediction of future behaviors of a phenomenon that is well known, and owning identified behavior. For such case, we illustrated the situation of prediction matched to observation operated in two cases. These are the Bayesian Brain theory in neuroscience and the Digital Twins industrial concept. The last investigated circumstance concerns the use of modeling for the prediction of future behaviors of a phenomenon that is not well known, or owning behavior varying arbitrary. For this situation, we studied contagion infections with an unknown mutant virus where the prediction task is very complicated and would be constrained only to adjust the principal clinical observation protocol. Keywords: prediction, observation, Bayesian, neuroscience, brain functioning, mutant virus

Temperature, Mitochondria, and Reye's Syndrome

PEDIATRICS ◽  
1983 ◽  
Vol 71 (6) ◽  
pp. 985-986
Author(s):  
R. DON BROWN ◽  
JOHN T. WILSON
Keyword(s):  
Mitochondrial Damage ◽  
Reye's Syndrome ◽  
Enhancing Effect ◽  
Control Subjects ◽  
Epidemiologic Data ◽  
Higher Temperature ◽  
And Control

In Reply.— El-Mallakh raises hypothetical questions about an enhancing effect of fever on mitochondrial damage associated with Reye's syndrome. Our article on aspirin and Reye's syndrome1 emphasized the role of prodromal illness in use of aspirin. Fever was only one of several [See table in the PDF] prodormal illness events that were different in patients as compared with control subjects. Results of our analysis of the epidemiologic data from the Ohio study reveal a statistically significant higher temperature in those children which Reye's syndrome as compared with unmatched control subjects (Table) as well as in patients and control subjects matched for record temperatures.1

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