Auditory evoked cortical responses to changes in the interaural phase difference (IPD) were recorded using magnetoencephalography (MEG). Twelve normal-hearing young adults were tested with amplitude-modulated tones with carrier frequencies of 500, 1000, 1250, and 1500 Hz. The onset of the stimuli evoked P1m-N1m-P2m cortical responses, as did the changes in ...

One of the prominent markers of end-stage heart failure at the molecular level is a decrease in function and/or expression of the sarcoplasmic reticulum ATPase protein [sarco(endo)plasmic reticulum calcium-ATPase, SERCA]. It has been often postulated that a decrease in SERCA pump activity can contribute in a major way to decreased ...

Acupuncture is a practice that has existed in Chinese society for thousands of years. Today, it is gaining greater acceptance and integration into medical practices of the western world. Its mechanism, however, remains elusive. Our study shows that only specific stimulation frequencies at specific acupoints will induce dopamine release in ...

The effects of the anesthetic ketamine on properties of inspiratory bursts (I-bursts) in mouse hypoglossal nerve activity were studied in vivo and in vitro. In urethane anesthetized mice we observed rhythmic I-phase activity in only one of eight pups at P9 days. In contrast in older mice rhythmic I-phase hypoglossal ...

There is currently a controversy over whether stimulation frequencies should increase or decrease to optimize force output over time. This study compared changes in thenar muscle force and M-wave amplitude during progressively increasing (20-40 Hz), decreasing (40-20 Hz) and constant (20 Hz) frequency stimulation of the median nerve continuously for ...

Although measurement of the detection limits of the 80 Hz auditory steady-state response (ASSR) has proven to be a reasonably reliable tool in estimating hearing sensitivity in the mid-conventional audiometric frequencies (e.g. 1000 and 2000 Hz), results in the literature suggest potentially diminishing performance at 500 Hz and above 4000 ...

Harmonic Medicine is the model using the theory that the body rhythms synchronize to an outer rhythm applied for therapeutic purpose, can restores the energy balance in acupuncture channels and organs and the condition of well-being. The purpose of this scientific work was to demonstrate the role played by harmonic ...

A piezoelectric (PZE) vibrator was used to mechanically drive the columella footplate and stimulate the cochlea of chicken embryos and hatchlings. Our objectives were to characterize the motion of the PZE driver and determine the relationship between columella footplate motion (displacement/ velocity) and the cochlear microphonic recorded from the recessus ...

The present study proposes to apply magnitude-squared coherence (MSC) to the somatosensory evoked potential for identifying the maximum driving response band. EEG signals, leads [Fpz'-Cz'] and [C3'-C4'], were collected from two groups of normal volunteers, stimulated at the rate of 4.91 (G1: 26 volunteers) and 5.13 Hz (G2: 18 volunteers). ...

Phase change refers to the transition between juvenile and adult vegetative phases. The study of trees throughout their entire life span requires retrospective analyses and validates the use of a chronosequence by sequencing observations at different and successive stages. The main axis growth pattern of 62 maritime pines (Pinus pinaster) ...

The consequences of rhythmical flow motion for nutrition and the oxygen supply to tissue are largely unknown. In this study, the periodic variations of haemoglobin oxygenation in compressed and uncompressed skin were evaluated with a reflection spectrometer using an in vivo Sprague-Dawley rat model. Skin compression was induced over the ...

Power spectra of short-term (less than 1 sec) electrical responses to conditioned stimuli were studied over the frequency range 1-225 Hz in dogs during food-related operant conditioning. These spectra demonstrated regional characteristics in terms of energy levels and frequency composition. Responses were more marked in the visual and parietal areas ...

Primary cold and warm afferent fibers show a robust overshoot in their firing during periods of temperature change, which subsides during tonic thermal stimulation. Our objective was to analyze cortical activation, on a scale of hundreds of milliseconds, occurring during the process of dynamic cooling and warming, based on an ...

PURPOSE: Intraoperative activation sequence mapping during atrial fibrillation (AF) is difficult because of the complexity of the data. The data analysis is time consuming, and picking activation times can be ambiguous. The purpose of this study was to determine whether mapping in the frequency domain during AF can be used ...

Steady-state responses were evoked by noise stimuli that alternated between two levels of interaural correlation rho at a frequency fm. With rho alternating between +1 and 0, responses at fm dropped steeply above 4 Hz, but persisted up to 64 Hz. Two time constants of 47 and 4.4 ms with ...

High frequency chest compression (HFCC) is used for treatment and prevention of the lung diseases characterized by impaired mucus clearance and/or cough, where patients are at risk for acquiring acute bronchitis or pneumonia. The HFCC treatment frequencies may be prescribed according to the manufacturers' generic guidelines or may be determined ...

Quantitative magnetoencephalography (qMEG) was used to investigate differences in the 2 to 60 Hz spectral power, between Alzheimer disease (AD) patients and control subjects. Twenty-two AD patients and 21 age-matched control subjects participated in this study. MEG signal analysis comprised the division of the entire 2 to 60 Hz spectrum ...

Oscillatory cerebral electric activity has been related to sensorial and perceptual-cognitive functions. The aim of this work is to investigate low frequency oscillations (<300 Hz), particularly within the gamma band (30-110 Hz), during tibial stimulation. Twenty-one volunteers were subjected to 5 Hz stimulation by current pulses of 0.2 ms duration ...

Repetitive transcranial magnetic stimulation (rTMS) has been shown to alter cortical excitability that lasts beyond the duration of rTMS application itself. High-frequency rTMS leads primarily to facilitation, whereas low-frequency rTMS leads to inhibition of the treated cortex. However, the contribution of rTMS train duration is less clear. In this study, ...

The objective of this study is to assess the effect of prolonged surface compression on the skin blood flowmotion in rats using spectral analysis based on wavelets transform of the periodic oscillations of the cutaneous laser Doppler flowmetry (LDF) signal. An external pressure of 13.3 kPa (100 mmHg) was applied ...

MFEIT (multi-frequency electrical impedance tomography) has the potential to provide a portable non-invasive neuroimaging method ideal for use in acute stroke. Skin perception has not previously occurred in MFEIT with injected frequencies above 2 kHz, but use in brain imaging requires applied current below 100 Hz, which could stimulate cutaneous ...

The aim of this study was to estimate the dynamic response of a human muscle joint unit by means of the analysis of the torque signal recorded during electrical stimulation of the tibialis anterior (TA). Ten subjects (age: 23-50 years, 7 males, 3 females) volunteered for the study. The leg ...

Strong synchronization of neuronal activity occurs in the 8-35 Hz band in the subthalamic nucleus (STN) of patients with Parkinson's disease (PD) and is evident as oscillatory local field potential (LFP) activity. To test whether such synchronization may contribute to bradykinesia and rigidity, we sought correlations between the suppression of ...

BACKGROUND: CPR prior to defibrillation improves survival from prolonged ventricular fibrillation (VF) by over 10%, based on recent studies. Waveform analysis could identify those patients with VF of over 5 to 7-min duration who should receive CPR first. A method based on the changes in the Fourier-derived frequency spectrum over ...

OBJECTIVE: In this study, we applied a novel procedure to calculate the mean frequency from the Magnetoencephalography (MEG) signals of 22 patients with Alzheimer's Disease (AD), 22 patients with mild cognitive impairment (MCI), and 21 healthy controls. A significant mean frequency decrease was expected in pathological groups. MCI subjects are ...

In late years, f-MRI (functional magnetic resonance imaging) are used for analysis of a visual function. In case of the study for a visual function, the checker flag pattern consists of white square and black square is usually used for sight stimulation. In sight stimulation using this pattern, a color ...

Tone-evoked Auditory Brainstem Responses (tone-burst ABRs) and Auditory Steady-State Responses (ASSRs) with 40 or 90 Hz amplitude modulation (AM) were compared, using the same equipment and recording parameters, to determine which of these three methods most accurately approached the behavioural hearing thresholds in response to 500 Hz and 2000 Hz ...

The multiple component synchrony measure (MCSM), a multivariate objective response detection (MORD) technique in the frequency domain, was applied to EEG signals during somatosensory stimulation of the right posterior tibial nerve collected from derivations [Fpz'-Cz'] and [C3'-C4'] of 10 adult volunteers. Stimuli were applied at the rate of 4.91 Hz ...

A Hidden Markov Model (HMM) is used to improve the robustness to noise when tracking the atrial fibrillation (AF) frequency in the ECG. Each frequency interval corresponds to a state in the HMM. Following QRST cancellation, a sequence of observed states is obtained from the residual ECG, using the short ...

Rats implanted with hippocampal recording electrodes were tested in a wheel-running apparatus under three conditions: (1) independent electrical stimulation of the medial septal nucleus (MS); (2) independent electrical stimulation of the posterior hypothalamic nucleus (PH); and (3) combined electrical stimulation of the MS and PH using pairings of two stimulation ...

In healthy subjects, suprathreshold repetitive transcranial magnetic stimulation (rTMS) at frequencies >2 Hz prolongs the cortical silent period (CSP) over the course of the train. This progressive lengthening probably reflects temporal summation of the inhibitory interneurons in the stimulated primary motor cortex (M1). In this study, we tested whether high-frequency ...

The existence of hippocampal high-frequency electrical activities (greater than 100 Hz) during the progression of seizure episodes in both human and animal experimental models of epilepsy has been well documented (Bragin A, Engel J, Wilson C L, Fried I and Buzsáki G 1999 Hippocampus 9 137-42; Khosravani H, Pinnegar C ...

The objective is to increase the number of selections in brain computer interfaces (BCI) by recording and analyzing the steady state visual evoked potential response to dual stimulation. A BCI translates the VEP signals into user commands. The frequency band from which stimulation frequency can be selected is limited for ...

This study evaluated the use of multiple auditory steady-state responses (ASSRs) and slow cortical potentials (SCPs) to estimate behavioural audiograms in adults for compensation cases. Two groups of 23 subjects were assessed using either 80 Hz or 40 Hz multiple simultaneous tones with carrier frequencies of 0.5, 1.0, 2.0, and ...

BACKGROUND: The dose-dependent suppression of midlatency auditory evoked potentials by general anesthetics has been proposed to measure depth of anesthesia. In this study, perioperatively recorded midlatency auditory evoked potentials were analyzed in a time-frequency space to identify significant changes induced by general anesthesia. METHODS: Perioperatively recorded auditory evoked potentials of ...

OBJECTIVE: To measure the frequency dynamics of the vestibular evoked myogenic potential in patients with endolymphatic hydrops. STUDY DESIGN: A prospective study. SETTING: A university hospital. SUBJECTS: The endolymphatic hydrops group consisted of 28 affected ears of patients with definite unilateral Ménière's disease and a control group of 36 ears ...

Brain-computer interfaces (BCIs) can be realized on the basis of steady-state evoked potentials (SSEPs). These types of brain signals resulting from repetitive stimulation have the same fundamental frequency as the stimulation but also include higher harmonics. This study investigated how the classification accuracy of a 4-class BCI system can be ...

Synaptic activation at low frequency is often used to probe synaptic function and synaptic plasticity, but little is known about how such low-frequency activation itself affects synaptic transmission. In the present study, we have examined how the perforant path-dentate granule cell (PP-GC) synapse adapts to low-frequency activation from a previously ...

A two-interval forced-choice (2-IFC) tracking procedure was used to evaluate the effects of a 15-s pre-exposure to either 25 Hz or 200 Hz stimulation ("25 Hz or 200 Hz adaptation") on human vibrotactile frequency discrimination threshold (frequency DL/Weber fraction). Three subjects were studied. All stimuli (standard and comparison) were delivered ...

Piezoelectric-excited millimeter-sized cantilever (PEMC) sensors consisting of a piezoelectric and a borosilicate glass layer with a sensing area of 2.48 mm2 were fabricated. Antibody specific to Bacillus anthracis (BA, Sterne strain 7702) spores was immobilized on PEMC sensors, and exposed to spores (300 to 3x10(6) spores/mL). The resonant frequency decreased ...

At a variety of fast chemical synapses, spent synaptic vesicles are recycled via a large 'reserve' vesicle pool at high stimulus frequencies, and via fast 'local cycling' near release sites (e.g. 'kiss and run' transmitter release) at low stimulus frequencies. We have investigated recycling at the snake neuromuscular junction (NMJ), ...

The reproducibility of baroreflex sensitivity (BRS in ms/mmHg; BRSf in mHz/mmHg) determined with respect to the coherence between the variability in systolic blood pressure (SBP) and inter-beat intervals (IBI) or heart rate (HR) was tested. SBP and IBI were recorded beat-to-beat for 5 min (Finapres, breathing at 0.33 Hz) in ...

PURPOSE: High-frequency oscillations (HFOs) in the range of > or = 80 Hz have been recorded in neocortical and hippocampal brain structures in vitro and in vivo and have been associated with physiologic and epileptiform neuronal population activity. Frequencies in the fast-ripple range (> 200 Hz) are believed to be ...

The purpose of the present study was to validate the capability of new fatigue indexes (in the time and frequency domain) applied to experimental recordings and thus, to test some assumptions made in previous simulations. The indexes were applied to M-waves detected non-invasively from human m.biceps brachii during repetitive slightly ...

To determine the skeletal muscle stimulation parameters that are most important in establishing vasodilation in the microvasculature, I tested whether arteriolar diameter during 2 min of repetitive, short-duration, tetanic skeletal muscle contractions increased with changes in stimulus frequency, stimulation train duration, and contraction frequency. To test this, the diameter of ...

Arterial pressure fluctuates rhythmically in healthy supine resting humans, who, from all outward appearances, are in a 'steady-state'. Others have asked, If baroreflex mechanisms are functioning normally, how can arterial pressure be so variable? We reanalysed data from nine healthy young adult men and women and tested the hypotheses that ...

Imaging of intrinsic optical signals has become an important tool in the neurosciences. To better understand processes underlying changes in intrinsic optical signals, we studied electrical stimulation at varying strengths in hippocampal slices of adult Wistar rats. Following serial stimulation we observed an increase in light transmittance in all tested ...

The surface and interior response of a Cessna Citation fuselage section under three different forcing functions (10-1000 Hz) is evaluated through spatially dense scanning measurements. Spatial Fourier analysis reveals that a point force applied to the stiffener grid provides a rich wavenumber response over a broad frequency range. The surface ...

We explored properties of whole brain networks based on multivariate spectral analysis of human functional magnetic resonance imaging (fMRI) time-series measured in 90 cortical and subcortical subregions in each of five healthy volunteers studied in the (no-task) resting state. We note that undirected graphs representing conditional independence between multivariate time-series ...

Synchronization of neuronal activity, often associated with network oscillations, is thought to provide a means for integrating anatomically distributed processing in the brain. Neuronal processing, however, involves simultaneous oscillations in various frequency bands. The mechanisms involved in the integration of such spectrally distributed processing have remained enigmatic. We demonstrate, using ...