scholarly journals What Can Local Transfer Entropy Tell us About Phase-amplitude Coupling in Electrophysiological Signals?

2020 ◽  
Author(s):  
Ramón Martínez-Cancino ◽  
Arnaud Delorme ◽  
Johanna Wagner ◽  
Kenneth Kreutz-Delgado ◽  
Roberto C. Sotero ◽  
...  
Keyword(s):  
Time Course ◽  
Mammalian Species ◽  
Transfer Entropy ◽  
Information Theoretic ◽  
Field Activity ◽  
Electrophysiological Signals ◽  
Brain Rhythm ◽  
Technical Issues ◽  
Phase Amplitude ◽  
Local Transfer

Modulation of the amplitude of high-frequency cortical field activity locked to changes in phase of a slower brain rhythm is known as phase-amplitude coupling (PAC). The study of this phenomenon has been gaining traction in neuroscience because of several reports on its appearance in normal and pathological brain processes in humans as well as across different mammalian species. This has led to the suggestion that PAC may be an intrinsic brain process that facilitates brain inter-area communication across different spatiotemporal scales. Several methods have been proposed to measure the PAC process, but few of these enable detailed study of its time course. It appears that no studies have reported details of PAC dynamics including its possible directional delay characteristics. Here, we study and characterize the use of a novel information theoretic measure that may address this limitation: local transfer entropy. We use both simulated and actual intracranial electroencephalographic data, and in both cases we observe initial indications that local transfer entropy can be used to detect the onset and offset of modulation process periods revealed by mutual information phase-amplitude coupling (MIPAC). We review our results in the context of current theories about PAC in brain electrical activity, and discuss technical issues that must be addressed to see local transfer entropy more widely applied to PAC analysis.

scholarly journals What Can Local Transfer Entropy Tell Us about Phase-Amplitude Coupling in Electrophysiological Signals?

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1262
Author(s):  
Ramón Martínez-Cancino ◽  
Arnaud Delorme ◽  
Johanna Wagner ◽  
Kenneth Kreutz-Delgado ◽  
Roberto C. Sotero ◽  
...  
Keyword(s):  
Mutual Information ◽  
Time Course ◽  
Mammalian Species ◽  
Transfer Entropy ◽  
Information Theoretic ◽  
Process Dynamics ◽  
Brain Rhythm ◽  
Technical Issues ◽  
Phase Amplitude ◽  
Local Transfer

Modulation of the amplitude of high-frequency cortical field activity locked to changes in the phase of a slower brain rhythm is known as phase-amplitude coupling (PAC). The study of this phenomenon has been gaining traction in neuroscience because of several reports on its appearance in normal and pathological brain processes in humans as well as across different mammalian species. This has led to the suggestion that PAC may be an intrinsic brain process that facilitates brain inter-area communication across different spatiotemporal scales. Several methods have been proposed to measure the PAC process, but few of these enable detailed study of its time course. It appears that no studies have reported details of PAC dynamics including its possible directional delay characteristic. Here, we study and characterize the use of a novel information theoretic measure that may address this limitation: local transfer entropy. We use both simulated and actual intracranial electroencephalographic data. In both cases, we observe initial indications that local transfer entropy can be used to detect the onset and offset of modulation process periods revealed by mutual information estimated phase-amplitude coupling (MIPAC). We review our results in the context of current theories about PAC in brain electrical activity, and discuss technical issues that must be addressed to see local transfer entropy more widely applied to PAC analysis. The current work sets the foundations for further use of local transfer entropy for estimating PAC process dynamics, and extends and complements our previous work on using local mutual information to compute PAC (MIPAC).

scholarly journals Role of Mammalian Auditory Cortex in the Perception of Elementary Sound Properties

2001 ◽  
Vol 85 (6) ◽  
pp. 2350-2358 ◽  
Author(s):  
Sanjiv K. Talwar ◽  
Pawel G. Musial ◽  
George L. Gerstein
Keyword(s):  
Auditory Cortex ◽  
Time Course ◽  
Auditory Evoked Potentials ◽  
Mammalian Species ◽  
Sound Intensity ◽  
Primary Auditory Cortex ◽  
Normal Hearing ◽  
Auditory Task ◽  
Experimental Conditions

Studies in several mammalian species have demonstrated that bilateral ablations of the auditory cortex have little effect on simple sound intensity and frequency-based behaviors. In the rat, for example, early experiments have shown that auditory ablations result in virtually no effect on the rat's ability to either detect tones or discriminate frequencies. Such lesion experiments, however, typically examine an animal's performance some time after recovery from ablation surgery. As such, they demonstrate that the cortex is not essential for simple auditory behaviors in the long run. Our study further explores the role of cortex in basic auditory perception by examining whether the cortex is normally involved in these behaviors. In these experiments we reversibly inactivated the rat primary auditory cortex (AI) using the GABA agonist muscimol, while the animals performed a simple auditory task. At the same time we monitored the rat's auditory activity by recording auditory evoked potentials (AEP) from the cortical surface. In contrast to lesion studies, the rapid time course of these experimental conditions preclude reorganization of the auditory system that might otherwise compensate for the loss of cortical processing. Soon after bilateral muscimol application to their AI region, our rats exhibited an acute and profound inability to detect tones. After a few hours this state was followed by a gradual recovery of normal hearing, first of tone detection and, much later, of the ability to discriminate frequencies. Surface muscimol application, at the same time, drastically altered the normal rat AEP. Some of the normal AEP components vanished nearly instantaneously to unveil an underlying waveform, whose size was related to the severity of accompanying behavioral deficits. These results strongly suggest that the cortex is directly involved in basic acoustic processing. Along with observations from accompanying multiunit experiments that related the AEP to AI neuronal activity, our results suggest that a critical amount of activity in the auditory cortex is necessary for normal hearing. It is likely that the involvement of the cortex in simple auditory perceptions has hitherto not been clearly understood because of underlying recovery processes that, in the long-term, safeguard fundamental auditory abilities after cortical injury.

scholarly journals Evolutionary conservation and modulation of a juvenile growth-regulating genetic program

2014 ◽  
Vol 52 (3) ◽  
pp. 269-277 ◽  
Author(s):  
Angela Delaney ◽  
Vasantha Padmanabhan ◽  
Geoffrey Rezvani ◽  
Weiping Chen ◽  
Patricia Forcinito ◽  
...  
Keyword(s):  
Body Size ◽  
Time Course ◽  
Mammalian Species ◽  
Genetic Program ◽  
Body Growth ◽  
Striking Similarity ◽  
Large Set ◽  
Adult Size ◽  
Large Mammals ◽  
Multiple Organs

Body size varies enormously among mammalian species. In small mammals, body growth is typically suppressed rapidly, within weeks, whereas in large mammals, growth is suppressed slowly, over years, allowing for a greater adult size. We recently reported evidence that body growth suppression in rodents is caused in part by a juvenile genetic program that occurs in multiple tissues simultaneously and involves the downregulation of a large set of growth-promoting genes. We hypothesized that this genetic program is conserved in large mammals but that its time course is evolutionarily modulated such that it plays out more slowly, allowing for more prolonged growth. Consistent with this hypothesis, using expression microarray analysis, we identified a set of genes that are downregulated with age in both juvenile sheep kidney and lung. This overlapping gene set was enriched for genes involved in cell proliferation and growth and showed striking similarity to a set of genes downregulated with age in multiple organs of the juvenile mouse and rat, indicating that the multiorgan juvenile genetic program previously described in rodents has been conserved in the 80 million years since sheep and rodents diverged in evolution. Using microarray and real-time PCR, we found that the pace of this program was most rapid in mice, more gradual in rats, and most gradual in sheep. These findings support the hypothesis that a growth-regulating genetic program is conserved among mammalian species but that its pace is modulated to allow more prolonged growth and therefore greater adult body size in larger mammals.

DATA DISCRETIZATION FOR THE TRANSFER ENTROPY IN FINANCIAL MARKET

2013 ◽  
Vol 12 (04) ◽  
pp. 1350019 ◽  
Author(s):  
XUEJIAO WANG ◽  
PENGJIAN SHANG ◽  
JINGJING HUANG ◽  
GUOCHEN FENG
Keyword(s):  
Financial Market ◽  
Information Flow ◽  
Coarse Graining ◽  
Transfer Entropy ◽  
Linear Modeling ◽  
Information Theoretic ◽  
Model Free ◽  
Temporal Correlations ◽  
Data Discretization ◽  
Flow Of Information

Recently, an information theoretic inspired concept of transfer entropy has been introduced by Schreiber. It aims to quantify in a nonparametric and explicitly nonsymmetric way the flow of information between two time series. This model-free based on Shannon entropy approach in principle allows us to detect statistical dependencies of all types, i.e., linear and nonlinear temporal correlations. However, we always analyze the transfer entropy based on the data, which is discretized into three partitions by some coarse graining. Naturally, we are interested in investigating the effect of the data discretization of the two series on the transfer entropy. In our paper, we analyze the results based on the data which are generated by the linear modeling and the ARFIMA modeling, as well as the dataset consists of seven indices during the period 1992–2002. The results show that the higher the degree of data discretization get, the larger the value of the transfer entropy will be, besides, the direction of the information flow is unchanged along with the degree of data discretization.

Expression of intermediate filament proteins during development of Xenopus laevis. II. Identification and molecular characterization of desmin

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 299-307 ◽  
Author(s):  
H. Herrmann ◽  
B. Fouquet ◽  
W.W. Franke
Keyword(s):  
Xenopus Laevis ◽  
Time Course ◽  
Mammalian Species ◽  
Sequence Divergence ◽  
Cytoskeletal Proteins ◽  
Similar Degree ◽  
Intermediate Filament Proteins ◽  
Muscle Tissues ◽  
The One ◽  
High Degree

During embryogenesis of avian and mammalian species the formation of intermediate filaments (IFs) containing desmin is characteristic for myogenesis. In view of important differences of patterns of IF protein expression in embryogenic pathways of amphibia on the one hand and birds and mammals on the other, we have decided to study the expression of desmin during early embryogenesis of Xenopus laevis by cDNA hybridization and antibody reactions. Here we describe the isolation of a cDNA clone encoding Xenopus desmin and the deduced amino acid sequence (458 residues; Mr 52,800) which displays a very high degree of conservation during vertebrate evolution from Xenopus to chicken and hamster, with a similar degree of sequence divergence between all three species compared. In addition, we have noted, by both cDNA-hybrid-selection-translation and immunoblotting of cytoskeletal proteins a second desmin-related polypeptide of Mr approximately 49,000. RNA (Northern) blot analyses show the occurrence of three different desmin mRNAs (1.9, 2.6 and 3.0 kb) which seem to represent different polyadenylation sites, displaying quantitative differences in different kinds of muscle tissues. During embryogenesis, desmin mRNA has first been detected in stage-14 embryos and then increases drastically to high levels at stage 18 and thereafter. Immunofluorescence microscopy using desmin-specific antibodies shows that this synthesis of desmin is restricted to somite tissue. The embryonic time course of synthesis of desmin and desmin mRNA is discussed in relation to those of other muscle proteins.

Contraction parameters, myosin composition and metabolic enzymes of the skeletal muscles of the etruscan shrew Suncus etruscus and of the common European white-toothed shrew Crocidura russula (Insectivora: soricidae)

1999 ◽  
Vol 202 (18) ◽  
pp. 2461-2473 ◽  
Author(s):  
T. Peters ◽  
H.P. Kubis ◽  
P. Wetzel ◽  
S. Sender ◽  
G. Asmussen ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Skeletal Muscles ◽  
Time Course ◽  
Citrate Synthase ◽  
Volume Fraction ◽  
Mammalian Species ◽  
Metabolic Enzymes ◽  
Diaphragm Muscle ◽  
Crocidura Russula ◽  
Contraction Times

In the Etruscan shrew, the isometric twitch contraction times of extensor digitorum longus (EDL) and soleus muscles are shorter than in any other mammal, allowing these muscles to contract at outstandingly high contraction frequencies. This species has the highest mass-specific metabolic rate of all mammals and requires fast skeletal muscles not only for locomotion but also for effective heat production and for an extremely high ventilation rate. No differences could be detected in the fibre type pattern, the myosin heavy and light chain composition, or in the activity of the metabolic enzymes lactate dehydrogenase and citrate synthase of the two limb muscles, the EDL and the soleus, which in larger mammalian species exhibit distinct differences in contractile proteins and metabolic enzymes. All properties determined in EDL and soleus muscles of Suncus etruscus, as well as in the larger Crocidura russula, are typical for fast-oxidative fibres, and the same holds for several other skeletal muscles including the diaphragm muscle of S. etruscus. Nevertheless, the EDL and soleus muscles showed different mechanical properties in the two shrew species. Relaxation times and, in C. russula, time to peak force are shorter in the EDL than in the soleus muscle. This is in accordance with the time course of the Ca(2+) transients in these muscles. Such a result could be due to different parvalbumin concentrations, to a different volume fraction of the sarcoplasmic reticulum in the two muscles or to different Ca(2+)-ATPase activities. Alternatively, the lower content of cytosolic creatine kinase (CK) in the soleus compared with the EDL muscle could indicate that the observed difference in contraction times between these shrew muscles is due to the CK-controlled activity of their sarcoplasmic reticulum Ca(2+)-ATPase.

Left ventricular torsion is equal in mice and humans

2000 ◽  
Vol 278 (4) ◽  
pp. H1117-H1123 ◽  
Author(s):  
R. E. Henson ◽  
S. K. Song ◽  
J. S. Pastorek ◽  
J. J. H. Ackerman ◽  
C. H. Lorenz
Keyword(s):  
Time Course ◽  
Mammalian Species ◽  
Tissue Level ◽  
Left Ventricular ◽  
Ventricular Ejection ◽  
Cine Mri ◽  
Wall Thickening ◽  
Left Ventricular Torsion ◽  
Healthy Humans ◽  
Ventricular Torsion

Global cardiac function has been studied in small animals with methods such as echocardiography, cine-magnetic resonance imaging (MRI), and cardiac catheterization. However, these modalities make little impact on delineation of pathophysiology at the tissue level. The advantage of tagged cine-MRI technique is that the twisting motion of the ventricle, referred to as torsion, can be measured noninvasively, reflecting the underlying shearing motion of individual planes of myofibrils that generate wall thickening and ventricular ejection. Thus we sought to determine whether the mechanism of ventricular ejection, as measured by torsion, was the same in both humans and mice. Nine mice and ten healthy humans were studied with tagged cine-MRI. The magnitude and systolic time course of ventricular torsion were equivalent in mouse and humans, when normalized for heart rate and ventricular length. The end-systolic torsion angle was 12.7 ± 1.7° in humans vs. 2.0 ± 1.5° in mice unnormalized and 1.9 ± 0.3°/cm vs. 2.7 ± 2.3°/cm when normalized for ventricular length). These results support the premise that ventricular torsion may be a uniform measure of normal ventricular ejection across mammalian species and heart sizes.

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