scholarly journals Effects of Sleep Deprivation on the Brain Electrical Activity in Mice

2021 ◽  
Vol 11 (3) ◽  
pp. 1182
Author(s):  
Alexey N. Pavlov ◽  
Alexander I. Dubrovskii ◽  
Olga N. Pavlova ◽  
Oxana V. Semyachkina-Glushkovskaya
Keyword(s):  
Sleep Deprivation ◽  
Electrical Activity ◽  
Fluctuation Analysis ◽  
Brain Health ◽  
Short Term ◽  
Scaling Exponents ◽  
Sleep Deficit ◽  
The Impact ◽  
Detrended Fluctuation ◽  
The Brain

Sleep plays a crucial role in maintaining brain health. Insufficient sleep leads to an enhanced permeability of the blood–brain barrier and the development of diseases of small cerebral vessels. In this study, we discuss the possibility of detecting changes in the electrical activity of the brain associated with sleep deficit, using an extended detrended fluctuation analysis (EDFA). We apply this approach to electroencephalograms (EEG) in mice to identify signs of changes that can be caused by short-term sleep deprivation (SD). Although the SD effect is usually subject-dependent, analysis of a group of animals shows the appearance of a pronounced decrease in EDFA scaling exponents, describing power-law correlations and the impact of nonstationarity as a fairly typical response. Using EDFA, we revealed an SD effect in 9 out of 10 mice (Mann–Whitney test, p<0.05) that outperforms the DFA results (7 out of 10 mice). This tool may be a promising method for quantifying SD-induced pathological changes in the brain.

The Impact of the COVID-19 Pandemic on Stock Markets

2020 ◽  
Vol 1 (2) ◽  
pp. 57-70
Author(s):  
Rui Dias ◽  
João Manuel Pereira
Keyword(s):  
Financial Markets ◽  
Global Economy ◽  
Structural Breaks ◽  
Research Question ◽  
Causal Link ◽  
Data Series ◽  
Fluctuation Analysis ◽  
Wald Tests ◽  
The Impact ◽  
Detrended Fluctuation

COVID-19 has had a marked impact on the global economy, resulting in uncertainty, pessimism, and adverse effects on financial markets. In light of this event, this paper aims to test whether the evolution of COVID-19 (confirmed cases and deaths) is responsible for the stock market indices in eight European countries, from December 31, 2019 to July 23, 2020. Two key research questions have been raised to determine this causal link: Does the increase in COVID-19 cases and deaths cause shockwaves in Europe's financial markets? If so, does the presence of long memories cause high levels of arbitration? The results show mostly structural breaks in March 2020. In contrast, the VAR Granger Causality/Block Exogeneity Wald Tests model shows that the COVID-19 data series (confirmed cases and deaths) do not cause shocks in Europe's financial markets, which in return does not validate the first research question. The results of the exponents detrended fluctuation analysis (DFA) shows significant long memories ranging between 0.61-0.73.

scholarly journals Effect of Sleep Deprivation on the Hippocampus of Adult and Senile Male Albino Rat: A Histological and Histochemical Study

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
S S I Elkilany ◽  
M M A Zakaria ◽  
R F Tash ◽  
A Y Mostafa ◽  
S W Abdelmalik ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Dentate Gyrus ◽  
Therapeutic Strategy ◽  
Control Group ◽  
Albino Rats ◽  
Free Access ◽  
Waste Products ◽  
Glymphatic System ◽  
The Impact ◽  
The Brain

Abstract Background The importance of sleep and the impact of its deprivation on development of brain pathology became a recent subject of interest in medicine. The restorative effect of sleep on the brain and the harmful effects of insomnia have been recently revealed through the discovery of the glymphatic system and its association with sleep. Aim of work Specific objectives are: To detect histological and apoptotic changes in the neurons and dendrites of the cornu Amonis and the dentate gyrus in sleep deprived rats in comparison to rats with undisturbed sleep pattern (control). To detect deposition of neurotoxic metabolites in comu Amonis and dentate gyrus in sleep deprived rats in comparison to controls. Methods Twenty four adult male Albino rats were used in the present experiment. randomly categorized into four equal groups; Group A1 served as the control group, Group .A2 one day sleep deprivation, Group A3 three days sleep deprivation and Group A4 seven days sleep deprivation. They were deprived of sleep using grid over water method where the animals placed over a grid suspended above tank filled with water with free access to food (rat chew) and water. Hippocampai specimens were collected, processed for paraffin blocks and examined by light microscopy. Results there were neurodegenerative signs appeared from day one sleep deprivation, increased by day three and prevailed by day seven. It was confirmed by apoptotic changes detected by caspase 3 immunohistochemical staining. Furthermore, deposition of beta amyloid appeared in rats deprived of sleep and confirmed by congo red stain. Conclusion Adequate sleep is essential for integrity of the newly discovered glymphatic system responsible for clearance of the brain from waste products including the area most involved in learning and memory function; the hippocampus. Correction of SD could be a viable therapeutic strategy to prevent the onset or slow the progression of AD. Recommendations Further characterization of the glymphatic system in humans are required, it may lead to new therapies and methods of prevention of neurodegenerative diseases. Correction of SD could be a viable therapeutic strategy to prevent the onset or slow the progression of AD.

Benzophenone-3 Passes Through the Blood-Brain Barrier, Increases the Level of Extracellular Glutamate, and Induces Apoptotic Processes in the Hippocampus and Frontal Cortex of Rats

2019 ◽  
Vol 171 (2) ◽  
pp. 485-500 ◽  
Author(s):  
Bartosz Pomierny ◽  
Weronika Krzyżanowska ◽  
Żaneta Broniowska ◽  
Beata Strach ◽  
Beata Bystrowska ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Blood Brain Barrier ◽  
Brain Structures ◽  
Glutamate Transporters ◽  
Brain Barrier ◽  
Short Term ◽  
Extracellular Glutamate ◽  
Blood Brain ◽  
The Impact ◽  
The Brain

Abstract Benzophenone-3 is the most commonly used UV filter. It is well absorbed through the skin and gastrointestinal tract. Its best-known side effect is the impact on the function of sex hormones. Little is known about the influence of BP-3 on the brain. The aim of this study was to show whether BP-3 crosses the blood-brain barrier (BBB), to determine whether it induces nerve cell damage in susceptible brain structures, and to identify the mechanism of its action in the central nervous system. BP-3 was administered dermally during the prenatal period and adulthood to rats. BP-3 effect on short-term and spatial memory was determined by novel object and novel location recognition tests. BP-3 concentrations were assayed in the brain and peripheral tissues. In brain structures, selected markers of brain damage were measured. The study showed that BP-3 is absorbed through the rat skin, passes through the BBB. BP-3 raised oxidative stress and induced apoptosis in the brain. BP-3 increased the concentration of extracellular glutamate in examined brain structures and changed the expression of glutamate transporters. BP-3 had no effect on short-term memory but impaired spatial memory. The present study showed that dermal BP-3 exposure may cause damage to neurons what might be associated with the increase in the level of extracellular glutamate, most likely evoked by changes in the expression of GLT-1 and xCT glutamate transporters. Thus, exposure to BP-3 may be one of the causes that increase the risk of developing neurodegenerative diseases.

Neurodynamical Control of the Heart of Healthy and Dying Crustacean Animals

2005 ◽  
Author(s):  
Toru Yazawa ◽  
Katsunori Tanaka ◽  
Tomoo Katsuyama
Keyword(s):  
Detrended Fluctuation Analysis ◽  
Terminal Condition ◽  
Fluctuation Analysis ◽  
Control Network ◽  
Cardiac Control ◽  
Freely Moving ◽  
Detrended Fluctuation ◽  
The Brain ◽  
Delayed Time ◽  
Embedding Methods

We analyzed the heartbeat-interval recorded from crustacean animals, using detrended fluctuation analysis (DFA) and delayed-time embedding method. EKG was obtained from freely moving animals in normal condition and then in terminal condition; we kept recording until the life was coming to an end. Our experimental purpose was to know whether DFA and embedding methods characterize quantitatively conditions of the cardiac control network, either in the brain or in the heart, or both, the brain and heart. We concluded that DFA exponents represent whether the subjects are under sick or healthy conditions. Here we show how the controller conditions of the brain changed and how pacemaker neural network in the heart deteriorated from time to time. This report demonstrates relationship between DFA and electro-physiological of the heart.

scholarly journals Investigating EEG Signals of Autistic Individuals Using Detrended Fluctuation Analysis

2021 ◽  
Vol 38 (5) ◽  
pp. 1515-1520
Author(s):  
Menaka Radhakrishnan ◽  
Karthik Ramamurthy ◽  
Avantika Kothandaraman ◽  
Gauri Madaan ◽  
Harini Machavaram
Keyword(s):  
Detrended Fluctuation Analysis ◽  
Autism Spectrum ◽  
Brain Diseases ◽  
Fluctuation Analysis ◽  
Typically Developing ◽  
Eeg Signals ◽  
Self Similarity ◽  
Detrended Fluctuation ◽  
Electroencephalogram Eeg ◽  
The Brain

To record all electrical activity of the human brain, an electroencephalogram (EEG) test using electrodes attached to the scalp is conducted. Analysis of EEG signals plays an important role in the diagnosis and treatment of brain diseases in the biomedical field. One of the brain diseases found in early ages include autism. Autistic behaviours are hard to distinguish, varying from mild impairments, to intensive interruption in daily life. The non-linear EEG signals arising from various lobes of the brain have been studied with the help of a robust technique called Detrended Fluctuation Analysis (DFA). Here, we study the EEG signals of Typically Developing (TD) and children with Autism Spectrum Disorder (ASD) using DFA. The Hurst exponents, which are the outputs of DFA, are used to find out the strength of self-similarity in the signals. Our analysis works towards analysing if DFA can be a helpful analysis for the early detection of ASD.

scholarly journals Trends and Persistence of Dry–Wet Conditions in Northeast Brazil

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1134
Author(s):  
Antonio Samuel Alves da Silva ◽  
Moacyr Cunha Filho ◽  
Rômulo Simões Cezar Menezes ◽  
Tatijana Stosic ◽  
Borko Stosic
Keyword(s):  
Time Scales ◽  
Water Resource Management ◽  
Standardized Precipitation Index ◽  
Kendall Test ◽  
Spatially Explicit ◽  
Fluctuation Analysis ◽  
Short Term ◽  
Agricultural Planning ◽  
Detrended Fluctuation

We analyze trend and persistence in Standardized Precipitation Index (SPI) time series derived from monthly rainfall data at 133 gauging stations in Pernambuco state, Brazil, using a suite of complementary methods to address the spatially explicit tendencies, and persistence. SPI was calculated for 1-, 3-, 6-, and 12-month time scales from 1950 to 2012. We use Mann–Kendall test and Sen’s slope to determine sign and magnitude of the trend, and detrended fluctuation analysis (DFA) method to quantify long-term correlations. For all time scales significant negative trends are obtained in the Sertão (deep inland) region, while significant positive trends are found in the Agreste (intermediate inland), and Zona da Mata (coastal) regions. The values of DFA exponents show different scaling behavior for different time scales. For short-term conditions described by SPI-1 the DFA exponent is close to 0.5 indicating weak persistency and low predictability, while for medium-term conditions (SPI-3 and SPI-6) DFA exponents are greater than 0.5 and increase with time scale indicating stronger persistency and higher predictability. For SPI-12 that describes long-term precipitation patterns, the values of DFA exponents for inland regions are around 1, indicating strong persistency, while in the shoreline the value of the DFA exponent is between 1.0 and 1.5, indicating anti-persistent fractional Brownian motion. These results should be useful for agricultural planning and water resource management in the region.

Complexity, Coordination, and Health: Avoiding Pitfalls and Erroneous Interpretations in Fractal Analyses

Medicina ◽  
2011 ◽  
Vol 47 (7) ◽  
pp. 393 ◽  
Author(s):  
Vivien Marmelat ◽  
Didier Delignières
Keyword(s):  
Long Range ◽  
Fluctuation Analysis ◽  
Short Term ◽  
Long Range Correlations ◽  
Optimal Functioning ◽  
Fractal Analyses ◽  
Serial Correlations ◽  
Walking Velocity ◽  
Fractal Fluctuation ◽  
Detrended Fluctuation

Background and Objective. The analysis of fractal fluctuation has become very popular because of the close relationships between health, adaptability, and long-range correlations. 1/f noise is considered a “magical” threshold, characterizing optimal functioning, and a decrease or conversely and increase of serial correlations, with respect to 1/f noise, is supposed to sign a kind of disadaptation of the system. Empirical results, however, should be interpreted with caution. In experimental series, serial correlations often present a complex pattern, resulting from the combination of long-range and short-term correlated processes. We show, in the present paper, that an increase in serial correlations cannot be directly interpreted as an increase in long-range correlations. Material and Methods. Eleven participants performed four walking bouts following 4 individually determined velocities (slow, comfortable, high, and critical). Series of 512 stride intervals were collected under each condition. The strength of serial correlation was measured by the detrended fluctuation analysis. The effective presence of 1/f fluctuation was tested through ARFIMA modeling. Results. The strength of serial correlations tended to increase with walking velocity. However, the ARFIMA modeling showed that long-range correlations were significantly present only at slow and comfortable velocities. Conclusions. The strength of correlations, as measured by classical methods, cannot be considered as predictive of the genuine presence of long-range correlations. Sometimes systems can present the moderate levels of effective long-range correlations, whereas in others cases, series can present high correlation levels without being long-range correlated.

scholarly journals APPLICATION OF DETRENDED FLUCTUATION ANALYSIS TO MONTHLY AVERAGE OF THE MAXIMUM DAILY TEMPERATURES TO RESOLVE DIFFERENT CLIMATES

Fractals ◽  
2004 ◽  
Vol 12 (04) ◽  
pp. 365-373 ◽  
Author(s):  
M. L. KURNAZ
Keyword(s):  
Time Trends ◽  
Detrended Fluctuation Analysis ◽  
Temperature Fluctuations ◽  
Fluctuation Analysis ◽  
Scaling Exponents ◽  
Monthly Average ◽  
Long Time ◽  
Data Points ◽  
Detrended Fluctuation ◽  
Different Climates

Detrended fluctuation analysis (DFA) is used to investigate correlations between the monthly average of the maximum daily temperatures for different locations in the continental United States and the different climates these locations have. When we plot the scaling exponents obtained from the DFA versus the standard deviation of the temperature fluctuations, we observe crowding of data points belonging to the same climates. Thus, we conclude that by observing the long-time trends in the fluctuations of temperature it would be possible to distinguish between different climates.

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