Stimulus train duration but not attention moderates γ-band entrainment abnormalities in schizophrenia

The cerebellum was stimulated with implanted chronic concentric stainless steel electrodes in ten cats, with isolation of current to the cortex immediately beneath the electrodes. Stimulus parameters were: current density 0.5–2.55 ma/mm2, pulse duration 1–2 msec., frequency 100 cycle/sec, stimulus train duration 10–15 sec. Elevation of bladder pressure, pupillary dilatation, and pupillary constriction were obtained at P values of 10–7–10–10; depression of bladder pressure at P < 10–5. Responsive areas included ansiform lobule and vermis.

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Effect of stimulus train duration and cycle frequency on the capacity to do work in the pectoral fin muscle of the pumpkinseed sunfish, Lepomis gibbosus

Canadian Journal of Zoology ◽

10.1139/z93-307 ◽

1993 ◽

Vol 71 (11) ◽

pp. 2185-2189 ◽

Cited By ~ 6

Author(s):

Eric A. Luiker ◽

E. Don Stevens

Keyword(s):

Duty Cycle ◽

Length Change ◽

Lepomis Gibbosus ◽

Pectoral Fin ◽

Cycle Frequency ◽

Pumpkinseed Sunfish ◽

Train Duration ◽

Stimulus Train ◽

Length Changes ◽

Time Required

The goal of our experiment was to elucidate the effect of stimulus duty cycle (the percentage of the cycle that the muscle was stimulated), phase (the relative timing of the imposed sinusoidal length change and stimulation), and muscle cycle frequency (the speed at which the muscle was cycled) on work and power in the pectoral fin muscle of a labriform swimmer, the pumpkinseed sunfish, Lepomis gibbosus. Stimulus train duration was varied from a twitch to a 40% duty cycle; cycle frequency was varied from 1 to 8 Hz. Work was calculated as the area of work loops produced by muscle contractions while the muscle was undergoing sinusoidal length changes. Maximum net work per cycle (6.2 J/kg) was produced at 1 Hz cycle frequency and a 32% duty cycle. Maximum power (26.7 W/kg) was produced at 5 Hz cycle frequency and a 16% duty cycle. As cycle frequency increased, the duty cycle and the stimulus train duration that produced maximum work decreased. The relatively long relaxation time compared with the length of time required to complete the whole cycle precluded the muscle from doing net positive work at high cycle frequencies.

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Effect of temperature and stimulus train duration on the departure from theoretical maximum work in fish muscle

Canadian Journal of Zoology ◽

10.1139/z94-132 ◽

1994 ◽

Vol 72 (6) ◽

pp. 965-969 ◽

Cited By ~ 4

Author(s):

Eric A. Luiker ◽

E. Don Stevens

Keyword(s):

Duty Cycle ◽

Relaxation Times ◽

Length Change ◽

Fish Muscle ◽

Effect Of Temperature ◽

Temperature Sensitive ◽

Theoretical Maximum ◽

Train Duration ◽

Stimulus Train ◽

Maximum Work

The goal of the present study was to compare the effect of temperature on contraction kinetic parameters of fish muscle with its effect on oscillatory work. In particular we studied the effect of stimulus train duration or duty cycle (the fraction of the imposed length change that the muscle was stimulated). We compared the actual work done by the muscle with a theoretical maximum work loop that would be achieved if it were fully and instantaneously relaxed at the onset of shortening and fully and instantaneously relaxed at the onset of lengthening. Temperature had a small effect on force but a marked effect on contraction and relaxation times. Thus, work was more temperature sensitive than force. The effect of temperature on work could not be predicted by its effect on any one contraction kinetic parameter. To achieve maximum work at lower temperatures, the duty cycle must be decreased because of the longer relaxation time.

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Self-Determined Stimulus Train Duration of Intracranial Self-Stimulation as a Function of Pulse Frequency in the Rat

Psychological Reports ◽

10.2466/pr0.1964.15.1.83 ◽

1964 ◽

Vol 15 (1) ◽

pp. 83-90 ◽

Cited By ~ 9

Author(s):

Murray S. Work ◽

S. Thomas Elder

Keyword(s):

Stimulus Intensity ◽

Electric Shock ◽

Response Duration ◽

Pulse Frequency ◽

Similar Relationship ◽

Bipolar Electrodes ◽

Train Duration ◽

Stimulus Train ◽

Self Stimulation

Six rats with bipolar electrodes chronically implanted were trained to press a lever to deliver a brief electric shock via the electrodes to the hypothalamus. The rats were subsequently allowed to maintain the current “on” for as long as the lever was depressed. Under this condition, mean response duration was found to be a decreasing, negatively accelerated function of frequency (pps). These results were discussed in the light of recent findings by Stein of a similar relationship with respect to stimulus intensity.

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Slow Afterhyperpolarization Governs the Development of NMDA Receptor–Dependent Afterdepolarization in CA1 Pyramidal Neurons During Synaptic Stimulation

Journal of Neurophysiology ◽

10.1152/jn.00977.2003 ◽

2004 ◽

Vol 92 (4) ◽

pp. 2346-2356 ◽

Cited By ~ 39

Author(s):

Wendy W. Wu ◽

C. Savio Chan ◽

John F. Disterhoft

Keyword(s):

Nmda Receptor ◽

Stimulus Intensity ◽

Pyramidal Neurons ◽

Stratum Radiatum ◽

Action Potential Firing ◽

Ca1 Pyramidal Neurons ◽

Train Duration ◽

Stimulus Train ◽

Potential Firing ◽

Intracellular Ca

CA1 pyramidal neurons from animals that have acquired a hippocampus-dependent task show a reduced slow postburst afterhyperpolarization (sAHP). To understand the functional significance of this change, we examined and characterized the sAHP activated by different patterns of synaptic stimuli and its impact on postsynaptic signal integration. Whole cell current-clamp recordings were performed on rat CA1 pyramidal neurons, and trains of stratum radiatum stimuli varying in duration, frequency, and intensity were used to activate the AHP. At −68 mV, a short train of subthreshold stimuli (20–150 Hz) generated only the medium AHP. In contrast, just two suprathreshold stimuli >50 Hz triggered a prominent sAHP sensitive to bath-applications of isoproterenol, carbachol, or intracellularly applied BAPTA, suggesting that the underlying current is the Ca2+-activated K+ current, the s IAHP. The sAHP magnitude was positively related to stimulus train duration and frequency, consistent with its dependence on intracellular Ca2+ accumulation for activation. About 20% of neurons recorded did not have a sAHP. In response to high-frequency suprathreshold stimuli, these neurons developed a pronounced afterdepolarization (ADP) and multiple action potential firing. The ADP magnitude increased with successive stimuli and was positively related to stimulus intensity and frequency. It was sensitive to bath-applications of thapsigargin and nitrendipine, and abolished by d-AP5, indicating that it is supported by intracellular Ca2+ release, the L-type Ca2+ influx, and N-methyl-d-aspartate (NMDA) receptor–mediated influx. In the presence of d-AP5, we were unable to trigger an ADP with maximal stimulus intensity. Pharmacologically eliminating the sAHP allowed neurons to develop an ADP with the original stimulus train. We propose that the slow AHP acts to facilitate Mg2+ re-block of the activated NMDA receptors, thereby reducing temporal summation and preventing an NMDA receptor–dependent ADP during intense synaptic events. Neuromodulation of the sAHP may thus affect information throughput and regulate NMDA receptor–mediated plasticity.

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Contraction-by-contraction V̇o2 and computer-controlled pump perfusion as novel techniques to study skeletal muscle metabolism in situ

Journal of Applied Physiology ◽

10.1152/japplphysiol.00963.2009 ◽

2010 ◽

Vol 108 (3) ◽

pp. 705-712 ◽

Cited By ~ 9

Author(s):

Andrés Hernández ◽

Matthew L. Goodwin ◽

Nicola Lai ◽

Marco E. Cabrera ◽

James R. McDonald ◽

...

Keyword(s):

Blood Flow ◽

Moving Average ◽

Computer Software ◽

Muscle Metabolism ◽

New Techniques ◽

Muscle Oxygen ◽

Flow Adjustment ◽

Train Duration ◽

Muscle Complex

The purpose of this research was to develop new techniques to 1) rapidly sample venous O2 saturation to determine contraction-by-contraction oxygen uptake (V̇o2), and 2) precisely control the rate and pattern of blood flow adjustment from one chosen steady state to another. An indwelling inline oximeter probe connected to an Oximetrix 3 meter was used to sample venous oxygen concentration ([O2]) (via fractional saturation of Hb with O2). Data from the Oximetrix 3 were filtered, deconvolved, and processed by a moving average second by second. Computer software and a program written in-house were used to control blood flow with a peristaltic pump. The isolated canine gastrocnemius muscle complex (GS) in situ was utilized to test these techniques. A step change in metabolic rate was elicited by stimulating GS muscles via their sciatic nerves (supramaximal voltage, 8 V; 50 Hz, 0.2-ms pulse width; train duration 200 ms) at a rate of either 1 contraction/2 s, or 2 contractions/3 s. With arterial [O2] maintained constant, blood flow and calculated venous [O2] were averaged over each contraction cycle and used in the Fick equation to calculate contraction-by-contraction V̇o2. About 5–8 times more data points were obtained with this method compared with traditional manual sampling. Software-controlled pump perfusion enabled the ability to mimic spontaneous blood flow on-kinetics (τ: 14.3 s) as well as dramatically speed (τ: 2.0 s) and slow (τ: 63.3 s) on-kinetics. These new techniques significantly improve on existing methods for mechanistically altering blood flow kinetics as well as accurately measuring muscle oxygen consumption kinetics during transitions between metabolic rates.

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Bioacoustic characterization of mating calls of a freshwater fish (Prochilodus magdalenae) for passive acoustic monitoring

Biota Colombiana ◽

10.21068/c2021.v22n01a07 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Sebastián Muñoz-Duque ◽

Silvia López-Casas ◽

Héctor Rivera-Gutiérrez ◽

Luz Jiménez-Segura

Keyword(s):

Pulse Rate ◽

Peak Frequency ◽

Acoustic Monitoring ◽

Passive Acoustic Monitoring ◽

Natural Habitats ◽

Train Duration ◽

Acoustic Characterization ◽

Species Specific ◽

Passive Acoustic

Fish produce sounds that are usually species-specific and associated with particular behaviors and contexts. Acoustic characterization enables the use of sounds as natural acoustic labels for species identification. Males of Prochilodus magdalenae produce mating sounds. We characterized these sounds and tested their use in natural habitats, to use passive acoustic monitoring for spawning ground identification. We identified two types of acoustic signals: simple pulses and pulse trains. Simple pulses were 13.7 ms long, with peak frequency of 365 Hz, whereas pulse train were 2.3 s long, had peak frequency of 399 Hz, 48.6 pulses and its pulses lasted 12.2 ms, with interpulse interval of 49.0 ms long and 22.3 Hz pulse rate. We did not detect spawning in absence of male calls nor differences in male sounds at different female densities. We found differences in train duration, pulse rate, and pulse duration in trains, according to the fish's source sites, but these sites were not well discriminated based on bioacoustical variables. In rivers, we located two P. magdalenae spawning grounds and recognized calls from another fish species (Megaleporinus muyscorum). We did not find a significant relationship between fish size and call peak frequency for P. magdalenae.

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High physiological levels of epinephrine do not enhance muscle glycogenolysis during tetanic stimulation

Journal of Applied Physiology ◽

10.1152/jappl.1994.77.2.956 ◽

1994 ◽

Vol 77 (2) ◽

pp. 956-962 ◽

Cited By ~ 5

Author(s):

A. Chesley ◽

D. J. Dyck ◽

L. L. Spriet

Keyword(s):

Tetanic Stimulation ◽

Control Groups ◽

Perfusion Medium ◽

Short Term ◽

Muscle Lactate ◽

Rest Perfusion ◽

Train Duration ◽

Fast Twitch ◽

And Control ◽

White Gastrocnemius

This study examined whether high physiological concentrations of epinephrine (EPI) would enhance muscle glycogenolysis during intense muscular contractions. Muscles of the rat hindlimb were perfused for 12 min at rest and 45 s of tetanic stimulation (1.0-Hz train rate, 100-ms train duration at 80 Hz) without EPI (control) or with 15 or 35 nM EPI. In the EPI groups the muscles were perfused with EPI for the last 2 min of rest perfusion and throughout stimulation. Glycogenolysis in the white gastrocnemius, red gastrocnemius, plantaris, and soleus muscles during stimulation was unaffected by the presence of EPI in the perfusion medium. In addition, muscle lactate and hindlimb lactate efflux were similar in EPI and control groups. It is concluded that EPI is not important for enhancing glycogenolysis in rat muscles composed predominantly of fast-twitch fibers during intense short-term tetanic stimulation.

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Properties of synaptic inputs from myenteric neurons innervating submucosal S neurons in guinea pig ileum

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.2000.278.2.g273 ◽

2000 ◽

Vol 278 (2) ◽

pp. G273-G280 ◽

Cited By ~ 16

Author(s):

B. A. Moore ◽

S. Vanner

Keyword(s):

Guinea Pig ◽

Myenteric Plexus ◽

Intracellular Recordings ◽

Guinea Pig Ileum ◽

Myenteric Neurons ◽

Synaptic Inputs ◽

Stimulus Train ◽

Stimulation Of ◽

Double Chamber

This study examined synaptic inputs from myenteric neurons innervating submucosal neurons. Intracellular recordings were obtained from submucosal S neurons in guinea pig ileal preparations in vitro, and synaptic inputs were recorded in response to electrical stimulation of exposed myenteric plexus. Most S neurons received synaptic inputs [>80% fast (f) excitatory postsynaptic potentials (EPSP), >30% slow (s) EPSPs] from the myenteric plexus. Synaptic potentials were recorded significant distances aboral (fEPSPs, 25 mm; sEPSPs, 10 mm) but not oral to the stimulating site. When preparations were studied in a double-chamber bath that chemically isolated the stimulating “myenteric chamber” from the recording side “submucosal chamber,” all fEPSPs were blocked by hexamethonium in the submucosal chamber, but not by a combination of nicotinic, purinergic, and 5-hydroxytryptamine-3 receptor antagonists in the myenteric chamber. In 15% of cells, a stimulus train elicited prolonged bursts of fEPSPs (>30 s duration) that were blocked by hexamethonium. These findings suggest that most submucosal S neurons receive synaptic inputs from predominantly anally projecting myenteric neurons. These inputs are poised to coordinate intestinal motility and secretion.

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Characterization of responses of neonatal sinus and AV nodes to critically timed, brief vagal stimuli

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1991.260.2.h459 ◽

1991 ◽

Vol 260 (2) ◽

pp. H459-H464 ◽

Cited By ~ 1

Author(s):

S. Yamasaki ◽

A. Stolfi ◽

A. S. Pickoff

Keyword(s):

Cycle Length ◽

Cardiac Cycle ◽

Gradual Increase ◽

Latency Period ◽

Atrial Pacing ◽

Response Curves ◽

Stimulus Train ◽

Sinus Cycle Length ◽

The Right

We studied the responses of sinus cycle length and atrioventricular (AV) nodal conduction to brief, critically timed vagal stimuli in 25 neonatal (9.6 +/- 3.1 days) canines. Vagal stimuli were delivered to the right or left decentralized cervical vagosympathetic trunk as either a single, brief stimulus train or a repetitive, phase-coupled train with both stimulation paradigms programmed to scan the entire cardiac cycle. The effects of brief vagal stimuli on cardiac cycle length were measured while the heart was beating spontaneously, and the vagal effects on AV nodal conduction were measured while the cycle length was held constant by atrial pacing at 300 ms. Neither changes in sinus cycle length nor AV nodal conduction demonstrated classical phase dependency, i.e., a gradual increase in the magnitude of the vagal response as stimuli are delivered progressively later in the cardiac cycle until the latency period (that point in the cardiac cycle at which vagal stimulation no longer affects the next cardiac cycle) is reached. Phase-response curves (PRCs) to single and repetitive stimuli typically exhibited either a flat response or a small decrease in magnitude as the latency period of the PRC was approached. Thus the neonatal sinus and AV node PRCs exhibit a different configuration than that reported in the adult.

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