Contrasting electro- or magnetoencephalographic oscillatory responses to sensory stimuli with a pre-stimulation baseline commonly yields spectrally broad and topographically distributed activations. In contrast, comparisons between closely matched task conditions usually result in more focal differences. In the present study, we reanalyzed an existing set of MEG data recorded during stimulation ...

Electrical stimulation for applications in epilepsy has been attempted in multiple brain regions [corrected] using high- or low-frequency stimulation protocols. Data suggest that specific frequencies may have more benefit at controlling seizure activity. To this end, investigators have tested low-frequency stimulation (LFS) protocols (0.1 to 25 Hz) in both animal ...

It is essential to determine optimal parameters of stimulation to maintain muscle force during neuromuscular electrical stimulation (NMES). Protocols that increase in frequency and include doublets can prolong force output over time. However, stimulation intensity level could differentially affect muscle force output during variable-frequency NMES. We compared three intermittent stimulation ...

We aimed to characterize the frequency spectra of skin blood flow signals recorded at Hoku, an important acupuncture point (acupoint) in oriental medicine. Electrocardiogram (ECG) and laser Doppler flowmetry signals were measured simultaneously in 31 trials on seven volunteers aged 21-27 years. A four-level Haar wavelet transform was applied to ...

Torque and laser detected surface mechanomyogram (MMG) analysis after electrical stimulation of human tibialis anterior (TA) of 14 male subjects was aimed to: (a) obtain the dynamic responses of TA muscle-joint unit from a long (LP, about 1h) and short (SP, 12.5s) stimulation protocol; (b) compare the resulting transfer function ...

BACKGROUND: Although a number of studies reported different interictal findings between migraine with aura (MA) and migraine without aura (MO), the pathophysiology of the visual aura in migraine remains unclear. OBJECTIVE: To investigate the visual processing in patients who experience MA between attacks using steady-state visual evoked potentials (SSVEPs). METHODS: ...

In 15 patients with primary dystonia (six cervical and nine generalized dystonias) who were treated with bilateral chronic pallidal stimulation, we investigated the sensorimotor modulation of the oscillatory local field potentials (LFPs) recorded from the pallidal electrodes. We correlated these with the surface electromyograms in the affected muscles. The effects ...

The whisper and croak modes of phonation provide convenient broad band excitation of the vocal tract and thus give relatively precise information about tract resonances. How closely do the measured resonances for these mechanisms approximate those of normal speech? We measured the frequencies of the first four resonances (R1-R4) in ...

Several available reports demonstrate the presence of infraslow activity (<0.5 Hz) in structures of the auditory system of the brain. It was reported earlier that specific alterations of this activity in the domain of seconds (0.1-0.5 Hz) occurred in the medial geniculate nucleus (MGN) and primary auditory cortex (A1) in ...

The Neurometer is a diagnostic device for measuring the perception and threshold of transcutaneous stimulation. It has been used in patients to selectively activate Abeta-, Adelta- and C-fibres in the primary afferents at different stimulus frequencies (2000, 250 and 5 Hz, respectively). In this study, we investigated use of the ...

Distortion product otoacoustic emission suppression (quantified as decrements) was measured for f(2)=500 and 4000 Hz, for a range of primary levels (L(2)), suppressor frequencies (f(3)), and suppressor levels (L(3)) in 19 normal-hearing subjects. Slopes of decrement-versus-L(3) functions were similar at both f(2) frequencies, and decreased as f(3) increased. Suppression tuning ...

To evaluate the impact of different ECG sampling frequencies on parameters of spectral and baroreflex analysis. Spectral and baroreflex analyses were performed in the EUROBAVAR data set (46 recordings of 23 persons) using the original ECG sampling frequency of 500 Hz and - simulated - sampling frequencies of 200 and ...

It is increasingly recognized that pain-induced plasticity may not only provoke sensory gain (hyperalgesia), but also sensory decline, i.e. hypoesthesia and hypoalgesia. We investigated perceptual changes by conditioning electrical stimulation of peptidergic C-nociceptors differing in stimulation frequencies and duty cycles at the left forearm. Four noxious electrical stimulation paradigms (Stim1: ...

Perceptual direction detection thresholds for yaw rotation about an earth-vertical axis were measured at seven frequencies (0.05, 0.1, 0.2, 0.5, 1, 2, and 5 Hz) in seven subjects in the dark. Motion stimuli consisted of single cycles of sinusoidal acceleration and were generated by a motion platform. An adaptive two-alternative ...

Sharp wave-ripple complexes (SPW-Rs) are characterized by approximately 60 ms field potential transients superimposed by ripple oscillations of approximately 200 Hz. In chronic epileptic rodents and humans, faster ripples have been recorded showing frequencies of up to 500 Hz. In this study, we tested whether the blockade of K currents ...

Cortical neurons are often classified by current-frequency relationship. Such a static description is inadequate to interpret neuronal responses to time-varying stimuli. Theoretical studies suggested that single-cell dynamical response properties are necessary to interpret ensemble responses to fast input transients. Further, it was shown that input-noise linearizes and boosts the response ...

This study assessed sex and individual differences in sway-position and velocity power spectra and reliability of power frequency with 30 health young people. The body sway for 1 min. was measured twice over a 1-min. rest. There were no significant sex differences in the spectra. Frequency bands with a large ...

The cortical response to repeated sensory stimuli plateaus (or declines) as repetition frequencies increase beyond 2-8 Hz. This study examined the underlying changes in cortical oxygenated and deoxygenated hemoglobin associated with this phenomenon using near-infrared spectroscopy. The optical signal was measured from 11 healthy volunteers listening to noise-burst trains presented ...

Stretch induces biphasic inotropic effects in mammalian myocardium. A delayed component (slow force response, SFR) has been demonstrated in various species, however, experimental conditions varied and the underlying mechanisms are controversial. The physiological relevance of the SFR is poorly understood. Experiments were performed in ventricular muscle strips from failing human ...

The buzz-pollinated genus Senna (Leguminosae) is outstanding for including species with monosymmetric flowers and species with diverse asymmetric, enantiomorphic (enantiostylous) flowers. To recognize patterns of homology, we dissected the floral symmetry character complex and explored corolla morphology in 60 Senna species and studied floral development of four enantiomorphic species. The ...

OBJECTIVES: To investigate the ability to identify consonant-vowel (CV) stimuli by individuals with auditory neuropathy (AN) when the envelope of the speech signal is enhanced by 15 dB for different modulation bandwidths (3 to 10 Hz; 3 to 20 Hz; 3 to 30 Hz; 3 to 60 Hz). DESIGN: Eight ...

There is an intense search for positive inotropic strategies. It is well known that the interbeat duration is a critical determinant of cardiac contractility. Generally, when frequency increases, so does contractile strength. We hypothesize that the beat-to-beat variability at a given heart rate also modulates cardiac contractility. To test this ...

Measuring the Apnoea Hypopnoea Index (AHI) is important for determining the severity of any apnoea patient. This study presents a method of screening each apnoea event separately based on the single lead Electrocardiogram (EGG) signal. The whole ECG of a subject was divided into Normal, Onset, OSA-maximum and Termination epochs ...

Moderate electric fields (MEF) have been previously shown to alter the metabolic activity of microbial cells; thus, the effect of frequency and electric field would be of considerable interest. We investigated herein the effects of MEF frequency on microbial growth kinetics and bacteriocin (Lacidin A) production of Lactobacillus acidophilus OSU ...

Objective.   For targeting the subthalamic nucleus (STN), we attempted to quantify the changes in multiple cell activities by computing the neural noise level and multiple-cell spike density (MSD). Methods.   We analyzed the neural noise level and MSD by stepwise recording at every 0.25-mm increment during the final tracking in 90 ...

In rainforests, trunk size, strength, crown position, and geometry of a tree affect light interception and the likelihood of mechanical failure. Allometric relationships of tree diameter, wood density, and crown architecture vs. height are described for a diverse range of rainforest trees in Brunei, northern Borneo. The understory species follow ...

Theta burst stimulation (TBS) is a special repetitive transcranial magnetic stimulation (rTMS) paradigm, where bursts of low-intensity stimuli are applied in the theta frequency. The aim of this study was to investigate the effect of neuronavigated TBS over primary somatosensory cortex (SI) on laser-evoked potentials (LEPs) and acute pain perception ...

Though high-frequency alternating current (HFAC) can block nerve conduction, the block is invariably preceded by an onset response which is a period of repetitive nerve firing. We tested the hypothesis that slowly ramping up the amplitude of the HFAC waveform could produce block without this initial onset response. Computer simulations ...

Steady-state potentials are oscillatory responses generated by rhythmic stimulation of a sensory pathway. The frequency of the response, which follows the frequency of stimulation and potentially indicates the preferential working frequency of the auditory neural network, is maximal at a stimulus rate of 40 Hz for auditory stimuli in humans, ...

There has been recent interest in using the parametric acoustic array for obtaining highly directional low frequency sources in acoustic landmine and IED detection. Experiments (using a commercial parametric array (0.5 m diam) located 1.5 m directly over the target and driven by a swept sine audio modulated 60 kHz ...

PURPOSE: To evaluate the influence of two stimulation frequencies on the installation of neuromuscular blockade produced by pancuronium and rocuronium on the rat diaphragm. METHODS: Diaphragms were submitted to an indirect frequency stimulation of 0.1 and 1 Hz (Groups I and II, respectively). Subgroups were formed (n=5) according to the ...

In this article the results are reported of a study to measure the intensity of the vocal displays of a population of American alligators (Alligator mississippiensis). It was found that the dominant frequencies in air range between 20 and 250 Hz with a source sound pressure level (SPL) of 91-94 ...

A battery of frequency-dependent measures was made for high-density electroencephalographic recording measured in response to a flash stimulus in 12 normal term infants within 2 d of birth. Significant changes recorded in posterior electrodes in the same time window as the visual evoked potential (VEP) included increased local synchrony at ...

BACKGROUND: Time-frequency analysis of the laser Doppler flowmetry signal, using wavelet transform, shows periodic oscillations at five characteristic frequencies related to the heart (0.6-2 Hz), respiration (0.15-0.6 Hz), myogenic activity in the vessel wall (0.052-0.15 Hz), sympathetic activity (0.021-0.052 Hz), and very slow oscillations (0.0095-0.021), which can be modulated by ...

Excessive synchronization of basal ganglia neural activity at low frequencies is considered a hallmark of Parkinson's disease (PD). However, few studies have unambiguously linked this activity to movement impairment through direct stimulation of basal ganglia targets at low frequency. Furthermore, these studies have varied in their methodology and findings, so ...

We used a 60-channel microelectrode array to study in thick (600-1000 microm) somatosensory cortical slices from postnatal day (P)0-P3 mice the spatio-temporal properties of early network oscillations. We recorded local non-propagating as well as large-scale propagating spontaneous oscillatory activity. Both types of activity patterns could never be observed in neocortical ...

In functional electrical stimulation (FES) the dynamics of tetanic muscle contractions is often described by the fusion frequency (FF), as determined by palpation: contractions elicited by stimulation frequencies above the FF appear smooth. To contribute to a more objective assessment of this important FES parameter, we have developed a dedicated ...

The oscillatory pattern of pial arterioles, i.e. vasomotion, has been described since early 1980s, but the impact of neural activation on such oscillations has never been formally examined. Sciatic nerve stimulation, a well characterized model for studying neurovascular coupling (NVC), leads to a neural activity-related increase of pial arteriolar diameter ...

A number of human and animal studies have reported a differential representation of the frequency of vibrotactile stimuli in the somatosensory cortices: neurons in the primary somatosensory cortex (SI) are predominantly responsive to lower frequencies of tactile vibration, and those in the secondary somatosensory cortex (SII) are predominantly responsive to ...

We studied the spatio-temporal characteristics of the resting state low-frequency fluctuations in fMRI-BOLD signal in isoflurane-anesthetized rats. fMRI-BOLD measurements at 9.4 T were made during normal and exsanguinated condition previously known to alter cerebral blood flow (CBF) fluctuations in anesthetized rats. fMRI signal time series were low pass filtered and ...

This research investigated the effects of continuous rotational perturbations of the support surface on postural control strategies adopted to maintain upright stance. Four different sinusoidal rotations of the support surface were employed: 0.5 Hz, at 2 degrees; 1.0 Hz at 1 degrees; 1.5 Hz at 4 degrees; and 2 Hz ...

Sensory receptors often receive strongly dynamic, or time varying, inputs in their natural environments. Characterizing their dynamic properties requires control and measurement of the stimulus over a frequency range that equals or exceeds the receptor response. Techniques for dynamic stimulation of olfactory receptors have lagged behind other major sensory modalities ...

OBJECTIVE: Time-frequency dynamics of spike-wave discharges (SWDs) were investigated in patients with absence seizures and in WAG/Rij rats, a genetic model of absence epilepsy using a specially developed wavelet transform. METHODS: Two types of SWDs were analyzed in both species: the most frequently occurring discharges (of minimal 3.6-4.0 s or ...

We describe an implantable stimulator with adjustable output amplitude and bi-directional communication at a size of approximately 1 cm(3). The user selects from preset patterns of stimulation and adjusts the stimulation amplitude by sending coded flashes of light, and receives active confirmation of the chosen settings via a powerful LED ...

AIMS: We investigated the process of spontaneous termination of atrial fibrillation (AF) to determine its time course from the surface ECG. METHODS AND RESULTS: We studied fibrillatory waves in Holter recordings of paroxysmal and sustained AF. Following QRS-T cancellation dominant frequencies (DFs) were computed and the relationship of DF to ...

The prevalence of shallow depth of concussion following captive bolt shooting was assessed in 1608 cattle at an abattoir. Depth of concussion was determined in each animal from physical collapse, presence or absence of corneal reflex, normal rhythmic breathing, eyeball rotation, and whether the animal was re-shot. The presence of ...

The middle latency response (MLR) to an acoustic stimulus occurs between 10 and 80 ms. The waveform is characterized by a series of peaks and troughs labeled N0, P0, Na, Pa, Nb and Pb. Certain acoustic stimuli may excite specific cochlear areas in contrast with clicks, that activate the cochlea ...

Neuromuscular electrical stimulation can generate contractions through peripheral and central mechanisms. Direct activation of motor axons (peripheral mechanism) recruits motor units in an unnatural order, with fatigable muscle fibers often activated early in contractions. The activation of sensory axons can produce contractions through a central mechanism, providing excitatory synaptic input ...

The work loop technique was used to examine contractile properties of the red aerobic locomotor muscle (RM) in the ectothermic leopard shark Triakis semifasciata and endothermic shortfin mako shark Isurus oxyrinchus. The effects of axial position and temperature on the twitch kinetics, and the stimulus duration and phase producing maximum ...

OBJECTIVE: To determine the efficacy of using modulated middle frequency alternating current (MFAC) muscle stimulation for functional electric stimulation-propelled cycling by people with spinal cord injury (SCI) compared with the conventional method of using standard low-frequency rectangular pulses (LFRP). DESIGN: Repeated-measures. SETTING: Laboratory setting. PARTICIPANTS: Eleven otherwise healthy volunteer subjects ...