scholarly journals Mixed Stimulus-Induced Mode Selection in Neural Activity Driven by High and Low Frequency Current under Electromagnetic Radiation

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Lulu Lu ◽  
Ya Jia ◽  
Wangheng Liu ◽  
Lijian Yang
Keyword(s):  
Electromagnetic Radiation ◽  
Neural Activity ◽  
High Frequency ◽  
Noise Intensity ◽  
Neuron Model ◽  
Mode Selection ◽  
Low Frequency ◽  
Electrical Activities ◽  
Selection Of ◽  
Frequency Current

The electrical activities of neurons are dependent on the complex electrophysiological condition in neuronal system, the three-variable Hindmarsh-Rose (HR) neuron model is improved to describe the dynamical behaviors of neuronal activities with electromagnetic induction being considered, and the mode transition of electrical activities in neuron is detected when external electromagnetic radiation is imposed on the neuron. In this paper, different types of electrical stimulus impended with a high-low frequency current are imposed on new HR neuron model, and mixed stimulus-induced mode selection in neural activity is discussed in detail. It is found that mode selection of electrical activities stimulated by high-low frequency current, which also changes the excitability of neuron, can be triggered owing to adding the Gaussian white noise. Meanwhile, the mode selection of the neuron electrical activity is much dependent on the amplitude B of the high frequency current under the same noise intensity, and the high frequency response is selected preferentially by applying appropriate parameters and noise intensity. Our results provide insights into the transmission of complex signals in nerve system, which is valuable in engineering prospective applications such as information encoding.

scholarly journals Modulation of Astrocytes on Mode Selection of Neuron Firing Driven by Electromagnetic Induction

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhongquan Gao ◽  
Zhixuan Yuan ◽  
Zuo Wang ◽  
Peihua Feng
Keyword(s):  
Membrane Potential ◽  
Resting State ◽  
Electromagnetic Induction ◽  
Neuron Model ◽  
Mode Selection ◽  
Neuron Firing ◽  
Two Factors ◽  
Selection Of ◽  
Strong Ability

Both of astrocytes and electromagnetic induction are magnificent to modulate neuron firing by introducing feedback currents to membrane potential. An improved astro-neuron model considering both of the two factors is employed to investigate their different roles in modulation. The mixing mode, defined by combination of period bursting and depolarization blockage, characterizes the effect of astrocytes. Mixing mode and period bursting alternatively appear in parameter space with respect to the amplitude of feedback current on neuron from astrocyte modulation. However, magnetic flux obviously plays a role of neuron firing inhibition. It not only repels the mixing mode but also suppresses period bursting. The mixing mode becomes period bursting mode and even resting state when astrocytes are hyperexcitable. Abnormal activities of astrocytes are capable to induce depolarization blockage to compose the mixing mode together with bursting mode. But electromagnetic induction shows its strong ability of inhibition of neuron firing, which is also illustrated in the bifurcation diagram. Indeed, the combination of the two factors and appropriate choice of parameters show the great potential to control disorder of neuron firing like epilepsy.

Generation of quasi-stationary magnetic fields by external electromagnetic radiation in a cold magneto-active plasma

1993 ◽  
Vol 49 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Yu. M. Aliev ◽  
B. M. Jovanović ◽  
A. A. Frolov
Keyword(s):  
Electromagnetic Radiation ◽  
High Frequency ◽  
Low Frequency ◽  
Active Plasma ◽  
Method Of Averaging ◽  
Hydrodynamic Equations ◽  
Cold Electron ◽  
Stationary Magnetic Field ◽  
High Frequency Oscillations ◽  
Space Time Evolution

Starting from the hydrodynamic equations for a cold electron fluid, we develop a theory of the ponderomotive effect of the interaction of high-frequency electromagnetic radiation with a magneto-active plasma. Using the method of averaging on high-frequency oscillations, we obtain expressions for the low- frequency nonlinear currents. We also obtain an equation describing the space–time evolution of a quasi-stationary magnetic field in the plasma.

scholarly journals A “Goldilocks” Approach to Hearing-Aid Self-Fitting: User Interactions

2017 ◽  
Vol 26 (3S) ◽  
pp. 430-435 ◽  
Author(s):  
Arthur Boothroyd ◽  
Carol Mackersie
Keyword(s):  
Speech Perception ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
User Interactions ◽  
Before And After ◽  
Fitting Procedures ◽  
Feasible Alternative ◽  
Highly Correlated ◽  
Selection Of

Purpose The purpose of the current study was to evaluate user reactions to custom software designed for self-adjustment of amplification. Method “Goldilocks” software was developed to allow user exploration and selection of preferred levels of overall output, low-frequency cut, and high-frequency boost while listening to preprocessed speech. Thirteen hearing-aid users and 13 nonusers self-adjusted before and after taking a speech perception test incorporated into the software. Results All 26 participants were able to complete the 2 adjustments and the intervening test in an average of 6.5 min—20 of them from on-screen instructions without experimenter help. Relative to a generic starting condition, the average participant opted to increase overall output, reduce low-frequency cut, and increase high-frequency boost. The first and second self-selected values were highly correlated, but there was evidence of further increases of overall volume and high-frequency boost after speech perception testing with the initial adjustment. There was no evidence that prior hearing-aid experience affected the ability to understand or complete the self-fitting process. Conclusions This approach to hearing-aid self-fitting can be a speedy, reliable, and feasible alternative to, or supplement to, conventional fitting procedures, but many questions remain to be answered.

scholarly journals Intrinsic coupling modes reveal the functional architecture of cortico-tectal networks

2015 ◽  
Vol 1 (7) ◽  
pp. e1500229 ◽  
Author(s):  
Iain Stitt ◽  
Edgar Galindo-Leon ◽  
Florian Pieper ◽  
Gerhard Engler ◽  
Eva Fiedler ◽  
...  
Keyword(s):  
Neural Activity ◽  
High Frequency ◽  
Receptive Fields ◽  
Low Frequency ◽  
Sensory Stimulation ◽  
Anatomical Connectivity ◽  
Spatial And Temporal Scales ◽  
Cortical Oscillations ◽  
Visual Spatial ◽  
Spatial Specificity

In the absence of sensory stimulation or motor output, the brain exhibits complex spatiotemporal patterns of intrinsically generated neural activity. Analysis of ongoing brain dynamics has identified the prevailing modes of cortico-cortical interaction; however, little is known about how such patterns of intrinsically generated activity are correlated between cortical and subcortical brain areas. We investigate the correlation structure of ongoing cortical and superior colliculus (SC) activity across multiple spatial and temporal scales. Ongoing cortico-tectal interaction was characterized by correlated fluctuations in the amplitude of delta, spindle, low gamma, and high-frequency oscillations (>100 Hz). Of these identified coupling modes, topographical patterns of high-frequency coupling were the most consistent with patterns of anatomical connectivity, reflecting synchronized spiking within cortico-tectal networks. Cortico-tectal coupling at high frequencies was temporally parcellated by the phase of slow cortical oscillations and was strongest for SC-cortex channel pairs that displayed overlapping visual spatial receptive fields. Despite displaying a high degree of spatial specificity, cortico-tectal coupling in lower-frequency bands did not match patterns of cortex-to-SC anatomical connectivity. Collectively, our findings demonstrate that neural activity is spontaneously coupled between cortex and SC, with high- and low-frequency modes of coupling reflecting direct and indirect cortico-tectal interactions, respectively.

Some chemical and physical aspects of muscle contraction and relaxation

1950 ◽  
Vol 137 (886) ◽  
pp. 63-70 ◽  
Keyword(s):  
Action Potential ◽  
Muscle Contraction ◽  
Muscle Cell ◽  
High Frequency ◽  
Low Frequency ◽  
High Frequency Current ◽  
Fast Decrease ◽  
Frequency Changes ◽  
Contraction And Relaxation ◽  
Frequency Current

We have been interested in three questions in relation to the problem which is under discussion to-day: the impedance changes, the pH changes and the protein changes during muscle contraction and relaxation. (a) Impedance changes With high-frequency current, we were not able to find any change in the conductivity of the muscle cell (Dubuisson 1935, 1936, 1937 a ). This confirms the earlier discoveries of MacClendon (1929) and Hartree (1933). At low frequency, changes were found due to modifications of some interfaces in the muscle cell. There is first of all a very fast decrease of impedance ( a wave) which occurs before the contraction and which is synchronous with the action potential (figure 8). Some years later, K. S. Cole (1938) found the same phenomenon in nerve.

scholarly journals Modeling and Simulation Technology of High Frequency Vibratory Stress Relief Treatment for Complex Thin -Walled Workpiece

2018 ◽  
Vol 206 ◽  
pp. 04001 ◽  
Author(s):  
Xian-yang Zhao ◽  
Nian-song Zhang ◽  
Ai-min Wang
Keyword(s):  
High Frequency ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Stress Relief ◽  
Response Analysis ◽  
Finite Element Software ◽  
Frequency Excitation ◽  
Thin Walled ◽  
Harmonic Response Analysis ◽  
Selection Of

The current research based on vibratory stress relief (VSR) is focused on low frequency excitation, but it is seldom mentioned for complex thin-walled workpiece with higher natural frequency. In this paper, the mechanism of high frequency VSR is studied by microdynamic theory. Aiming at the rotating frame of complex thin-walled workpiece in aerospace equipment, the high frequency VSR numerical simulation is carried out by finite element software Abaqus, the modal analysis technology and harmonic response analysis technology are proposed, and the exciting force, excitation frequency and other important parameters are determined. The simulation results are analyzed to verify the superiority of high frequency VSR to eliminate residual stresses of complex thin-walled workpieces, and provide a theoretical basis for optimal selection of excitation parameters for high frequency VSR.

scholarly journals The effect of superposed alternating current on the polarisable primary cell zinc-sulphric acid-carbon. Part II.—High frequency current

1926 ◽  
Vol 112 (760) ◽  
pp. 252-258 ◽  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Alternating Current ◽  
Primary Cell ◽  
Carbon Electrode ◽  
Current Output ◽  
High Frequency Current ◽  
Anodic Solution ◽  
The Subject ◽  
Frequency Current

In Part I of this investigation, It was shown that, when alternating currents of frequencies between 20 and 400 per second are passed through the primary cell zinc-sulphuric acid-carbon, the depolarisation and increase in current output first observed by Brown, are essentially due to an effect produced at the carbon electrode, the potential of which becomes more positive by an amount depending on the strength and frequency of the alternating current used. The greater this current and the lower its frequency, the greater the effect, a result quite in line with what was already known on the subject of the action of, superposed alternating currents on polarised electrodes. Brown had, however, also obtained a marked action when using a current of 12000 periods, and had ascribed it to an effect produced at the zinc electrode. The results of Allmand and Puri indicated that such high-frequency current would be unlikely to depolarise the carbon electrode perceptibly. In addition, the anodic solution of zinc is usually regarded as occurring almost reversibly, although Allmand and Puri had certainly noticed a small depolarising effect caused by their low frequency currents. Consequently, the results reported by Brown with a frequency of 12000 appeared to merit further investigation, and the present paper contains an account of experiments to this end.

Speech Discrimination in Noise: The Influence of Hearing Protection

1987 ◽  
Vol 31 (11) ◽  
pp. 1246-1250 ◽  
Author(s):  
John G. Casali ◽  
Matthew J. Horylev
Keyword(s):  
Spectral Type ◽  
High Frequency ◽  
Noise Intensity ◽  
Low Frequency ◽  
Discrimination Performance ◽  
Hearing Protection ◽  
Intensity Level ◽  
Hearing Level ◽  
Speech Discrimination ◽  
Independent Variables

A psychoacoustic study was performed to determine speech discrimination performance in several noise conditions with the use or non-use of industrial hearing protection. The independent variables included: (1) subject hearing configuration (unoccluded and earplug-, earcap-, or earmuff-occluded), noise intensity level (60, 83 dBA), and noise spectral type (low frequency, white, high frequency). Subjects' hearing level was used as a blocking variable. All factors were found to significantly influence speech discrimination performance, as measured using phoneme scoring. These are discussed in some detail in the paper.

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