Interpulse interval discrimination within and across channels: Comparison of monopolar and tripolar mode of stimulation

2014 ◽  
Vol 135 (5) ◽  
pp. 2913-2922 ◽  
Author(s):  
Claire A. Fielden ◽  
Karolina Kluk ◽  
Colette M. McKay
Keyword(s):  
Interpulse Interval ◽  
Tripolar Mode

scholarly journals Sitagliptin decreases visceral fat and blood glucoses in women with polycystic ovarian syndrome

2019 ◽  
Author(s):  
Jessica K. Devin ◽  
Hui Nian ◽  
Jorge E. Celedonio ◽  
Patricia Wright ◽  
Nancy J. Brown
Keyword(s):  
Body Composition ◽  
Half Life ◽  
Vascular Function ◽  
Polycystic Ovarian Syndrome ◽  
Interpulse Interval ◽  
Oral Glucose ◽  
Insulinogenic Index ◽  
Glucose Response ◽  
Gh Secretion ◽  
Ovarian Syndrome

ContextWomen with polycystic ovarian syndrome (PCOS) have decreased growth hormone (GH), which can increase visceral adiposity (VAT) and impair vascular function. GH releasing hormone, a dipeptidyl peptidase-4 (DPP4) substrate, stimulates GH secretion.ObjectiveWe tested the hypothesis that DPP4 inhibition increases GH and improves glucose levels and vascular function in women with PCOS.MethodsEighteen women with PCOS participated in a double-blinded, cross-over study. They received sitagliptin 100 mg vs. placebo daily for one month separated by an eight-week washout. During each treatment, women underwent a 75-gram oral glucose tolerance test (OGTT), assessment of vascular function and body composition. Overnight GH secretion was assessed via venous sampling every 10 minutes for 12 hours and analyzed using an automated deconvolution algorithm.ResultsDuring OGTT, sitagliptin increased GLP-1 (p<0.001), early insulin secretion (from mean insulinogenic index 1.9±1.2 (SD) to 3.2±3.1; p=0.02) and decreased peak glucose (mean −17.2 mg/dL [95% CI −27.7, −6.6]; p<0.01). At one month, sitagliptin decreased VAT (from 1141.9±700.7 to 1055.1±710.1 g; p=0.02) but did not affect vascular function. Sitagliptin increased GH half-life (from 13.9±3.6 to 17.0±6.8 min, N=16; p=0.04) and interpulse interval (from 53.2±20.0 to 77.3±38.2 min, N=16; p<0.05) but did not increase mean overnight GH (p=0.92 vs. placebo).ConclusionsSitagliptin decreased the maximal glucose response to OGTT and VAT. Sitagliptin did not increase overnight GH but increased GH half-life and the interpulse interval.PrecisSitagliptin improved body composition and blood glucoses following oral glucose load in women with PCOS. Sitagliptin potentiated GH half-life but did not increase overnight GH levels.

Variability of pulsatile luteinizing hormone secretion in young male volunteers

1994 ◽  
Vol 131 (3) ◽  
pp. 263-272 ◽  
Author(s):  
Carl-Joachim Partsch ◽  
Sievert Abrahams ◽  
Niels Herholz ◽  
Michael Peter ◽  
Johannes D Veldhuis ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Half Life ◽  
Hormone Secretion ◽  
Young Male ◽  
Interpulse Interval ◽  
Luteinizing Hormone Secretion ◽  
Individual Subject ◽  
Deconvolution Analysis ◽  
Pulse Detection ◽  
Male Volunteers

Partsch C-J, Abrahams S, Herholz N, Peter M, Veldhuis JD, Sippell WG. Variability of pulsatile luteinizing hormone secretion in young male volunteers. Eur J Endocrinol 1994;131:263–72. ISSN 0804–4643 Characteristics of spontaneous pulsatile luteinizing hormone secretion were compared in ten young healthy men in three 24-h profiles obtained at intervals of 14 days and 3 months. The ages of the volunteers ranged from 19 to 25 years, and heights and weights were within normal limits. Blood samples were taken at 10-min intervals and plasma luteinizing hormone (LH) was determined in the same immunoradiometric assay using monoclonal antibodies. Conventional pulse detection was carried out with PULSAR and CLUSTER programs. In addition, a simultaneous multiple parameter DECONVOLUTION was applied. As a group, no significant differences between the three profile series were found for any of the calculated parameters of LH concentration or LH secretion. However, most parameters showed low correlation coefficients between the three study periods, suggesting that substantial individual variations might contribute to the more reliable group results. Median coefficients of variation (cv) for the individual subject ranged from 9.7% (interpulse interval and endogenous half-life) to 37.7% (mass per burst). However, the maximal individual cv observed was 78.4%. Intra-individual variability was lower than the variability between subjects for quantitative properties of LH concentration and secretion, although not significantly so for all parameters. In conventional pulse detection, the highest individual reliability was found for mean and integrated LH concentrations (median cv 10.2 and 13.7%, respectively), number of pulses per 24 h (CLUSTER, median cv 12.2%), mean pulse amplitude (PULSAR, median cv 10%) and interpulse interval (CLUSTER, median cv 9.7%). In DECONVOLUTION analysis, the endogenous LH half-life (median cv 9.7%), secretory burst amplitude (median cv 14.8%) and interburst interval (median cv 14.5%) revealed the lowest intra-individual variation. In contrast, the half-duration of a secretory episode and the mass of LH secreted per burst proved to be the least reliable measures (median cv 32.7% and 37.7%, respectively). Calculated endogenous LH production rates correlated highly (p < 0.01) across all three sessions. The relative frequencies of the LH peak amplitudes/heights and peak widths (durations) showed almost identical distribution curves for all three sampling periods. In conclusion, a high reproducibility of group results for both integrative parameters and pulse characteristics of LH concentrations and secretion were found in normal men. However, intra-individual reliability was variable and at times considerable, depending on the parameter chosen. These observations suggest caution in the interpretation of single LH profiles from individual subjects or patients unless the variation reported herein is considered. C-J Partsch, Institut für Reproduktionsmedizin, Westfälische Wilhelms-Universität, Steinfurter Straβe 107, D-48149 Münster, Germany

THE EFFECT OF HIGH AND LOW FREQUENCY CORTICAL STIMULATION WITH A FIXED OR A POISSON DISTRIBUTED INTERPULSE INTERVAL ON CORTICAL EXCITABILITY IN RATS

2014 ◽  
Vol 24 (02) ◽  
pp. 1430005 ◽  
Author(s):  
INE BUFFEL ◽  
ALFRED MEURS ◽  
ROBRECHT RAEDT ◽  
VEERLE DE HERDT ◽  
LEEN DECORTE ◽  
...  
Keyword(s):  
High Frequency ◽  
Refractory Epilepsy ◽  
Cortical Excitability ◽  
Low Frequency ◽  
Cortical Stimulation ◽  
Interpulse Interval ◽  
Motor Cortex Stimulation ◽  
Low Intensity ◽  
Promising Treatment ◽  
Neocortical Epilepsy

Neurostimulation is a promising treatment for refractory epilepsy. We studied the effect of cortical stimulation with different parameters in the rat motor cortex stimulation model. High intensity simulation (threshold for motor response - 100 μA), high frequency (130 Hz) stimulation during 1 h decreased cortical excitability, irrespective of the interpulse interval used (fixed or Poisson distributed). Low intensity (10 μA) and/or low frequency (5 Hz) stimulation had no effect. Cortical stimulation appears promising for the treatment of neocortical epilepsy if frequency and intensity are high enough.

scholarly journals A consensus layer V pyramidal neuron can sustain interpulse-interval coding

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0180839 ◽  
Author(s):  
Chandan Singh ◽  
William B. Levy
Keyword(s):  
Pyramidal Neuron ◽  
Interpulse Interval ◽  
Layer V

scholarly journals Point process temporal structure characterizes electrodermal activity

2020 ◽  
Vol 117 (42) ◽  
pp. 26422-26428
Author(s):  
Sandya Subramanian ◽  
Riccardo Barbieri ◽  
Emery N. Brown
Keyword(s):  
Electrodermal Activity ◽  
Probability Model ◽  
Temporal Structure ◽  
Electrical Conductance ◽  
Gaussian Model ◽  
Interpulse Interval ◽  
Inverse Gaussian ◽  
Integrate And Fire ◽  
Model Set ◽  
Settling Rates

Electrodermal activity (EDA) is a direct readout of the body’s sympathetic nervous system measured as sweat-induced changes in the skin’s electrical conductance. There is growing interest in using EDA to track physiological conditions such as stress levels, sleep quality, and emotional states. Standardized EDA data analysis methods are readily available. However, none considers an established physiological feature of EDA. The sympathetically mediated pulsatile changes in skin sweat measured as EDA resemble an integrate-and-fire process. An integrate-and-fire process modeled as a Gaussian random walk with drift diffusion yields an inverse Gaussian model as the interpulse interval distribution. Therefore, we chose an inverse Gaussian model as our principal probability model to characterize EDA interpulse interval distributions. To analyze deviations from the inverse Gaussian model, we considered a broader model set: the generalized inverse Gaussian distribution, which includes the inverse Gaussian and other diffusion and nondiffusion models; the lognormal distribution which has heavier tails (lower settling rates) than the inverse Gaussian; and the gamma and exponential probability distributions which have lighter tails (higher settling rates) than the inverse Gaussian. To assess the validity of these probability models we recorded and analyzed EDA measurements in 11 healthy volunteers during 1 h of quiet wakefulness. Each of the 11 time series was accurately described by an inverse Gaussian model measured by Kolmogorov–Smirnov measures. Our broader model set offered a useful framework to enhance further statistical descriptions of EDA. Our findings establish that a physiologically based inverse Gaussian probability model provides a parsimonious and accurate description of EDA.

The Representation of Amplitude Modulations in the Mammalian Auditory Midbrain

2008 ◽  
Vol 100 (3) ◽  
pp. 1602-1609 ◽  
Author(s):  
Bjarne Krebs ◽  
Nicholas A. Lesica ◽  
Benedikt Grothe
Keyword(s):  
Auditory System ◽  
Duty Cycle ◽  
Modulation Frequency ◽  
Acoustic Signals ◽  
Interpulse Interval ◽  
Neural Responses ◽  
Stimulus Amplitude ◽  
Auditory Midbrain ◽  
Pulse Trains ◽  
The Relationship

Temporal modulations in stimulus amplitude are essential for recognizing and categorizing behaviorally relevant acoustic signals such as speech. Despite this behavioral importance, it remains unclear how amplitude modulations (AMs) are represented in the responses of neurons at higher levels of the auditory system. Studies using stimuli with sinusoidal amplitude modulations (SAMs) have shown that the responses of many neurons are strongly tuned to modulation frequency, leading to the hypothesis that AMs are represented by their periodicity in the auditory midbrain. However, AMs in general are defined not only by their modulation frequency, but also by a number of other parameters (duration, duty cycle, etc.), which covary with modulation frequency in SAM stimuli. Thus the relationship between modulation frequency and neural responses as characterized with SAM stimuli alone is ambiguous. In this study, we characterize the representation of AMs in the gerbil inferior colliculus by analyzing neural responses to a series of pulse trains in which duration and interpulse interval are systematically varied to quantify the importance of duration, interpulse interval, duty cycle, and modulation frequency independently. We find that, although modulation frequency is indeed an important parameter for some neurons, the responses of many neurons are also strongly influenced by other AM parameters, typically duration and duty cycle. These results suggest that AMs are represented in the auditory midbrain not only by their periodicity, but by a complex combination of several important parameters.

Temporal Integration Can Readily Switch Between Sublinear and Supralinear Summation

1998 ◽  
Vol 79 (5) ◽  
pp. 2809-2813 ◽  
Author(s):  
Michael Margulis ◽  
Cha-Min Tang
Keyword(s):  
Optical Fibers ◽  
Hippocampal Neurons ◽  
Temporal Summation ◽  
Temporal Integration ◽  
Single Mode ◽  
Interpulse Interval ◽  
Cable Theory ◽  
Cable Properties ◽  
Novel Method ◽  
Acting In Concert

Margulis, Michael and Cha-Min Tang. Temporal integration can readily switch between sublinear and supralinear summation. J. Neurophysiol. 79: 2809–2813, 1998. Temporal summation at dendrites of cultured rat hippocampal neurons was examined as a function of the interval separating two dendritic inputs. A novel method that relies on single-mode optical fibers to achieve rapid photorelease of glutamate was developed. Dendritic excitation achieved with this approach resembles that associated with miniature excitatory postsynaptic currents (mEPSCs), but the strengths, sites, and timing of the inputs can be precisely controlled. Dendritic summation deviated markedly from behavior predicted by passive cable theory. Subthreshold temporal summation varied as a triphasic function of the interpulse interval. As the interpulse interval decreased, local dendritic Na+ conductances were recruited to generate a marked transition from sublinear to supralinear summation. These results suggest that active dendritic conductances acting in concert with passive cable properties may serve to boost coincident synaptic inputs and attenuate noncoincident inputs.

Secretion rates and short-term patterns of gonadotrophin-releasing hormone, FSH and LH in the normal stallion in the breeding season

1988 ◽  
Vol 117 (2) ◽  
pp. 197-206 ◽  
Author(s):  
C. H. G. Irvine ◽  
S. L. Alexander
Keyword(s):  
Breeding Season ◽  
Venous Blood ◽  
Pulse Amplitude ◽  
Interpulse Interval ◽  
Statistical Testing ◽  
Pulse Interval ◽  
Apparent Difference ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
Lh Secretion

ABSTRACT Pituitary venous blood was collected by a painless non-surgical cannulation method from five ambulatory stallions at 5-min intervals for 5–6 h during the breeding season. In four adult stallions, statistical analysis showed that pulses of gonadotrophin-releasing hormone (GnRH) and LH were coincident (P <0·01), as were pulses of FSH and LH (P <0·05). Furthermore, the patterns of changes in concentration of FSH and LH were highly correlated in each of the four stallions. However, seemingly ineffective pulses of GnRH were also observed, with 28% of GnRH pulses failing to induce a significant gonadotrophin pulse. In the four adult stallions the amplitude of pituitary venous gonadotrophin pulses varied markedly but no correlation with GnRH pulse amplitude was observed. Peak secretion of FSH, but not LH, during pulses was correlated with the length of the interpulse interval. Consequently, the ratio of FSH to LH during peaks was least (P <0·02) when the interpulse interval was 30 min or less. Thus, differential FSH and LH secretion was achieved within a constant steroid milieu. Two stallions had regular contact with oestrous mares, and in these horses the secretion of GnRH and gonadotrophins occurred almost continuously with rapid, rhythmic pulses superimposed upon a tonic background. Mean (± s.d.) interval between GnRH pulses was 31·4 ± 9·8 min and 27·7 ± 10·1 min. This secretory pattern was not observed in the two stallions which had infrequent contact with oestrous mares, although the small numbers precluded statistical testing of this apparent difference. No GnRH pulses were observed in one of these stallions, while in the other mean (± s.d.) GnRH pulse interval was 45·0 ± 48·7 min, the large variance being partly due to rapid pulses during a period in which the stallion teased mares. The fifth stallion was pubertal, and GnRH and LH secretion occurred in 15 and 0% of samples respectively, while low levels of FSH secretion were observed in 37% of samples and jugular testosterone levels were immeasurably low. We conclude that there is a statistically significant synchrony between pulses of GnRH, LH and FSH in the pituitary venous blood of stallions. Furthermore, decreasing intervals between gonadotrophin pulses result in a significant reduction in secretion of FSH but not LH. J. Endocr. (1988) 117, 197–206

Sign in / Sign up

Export Citation Format

Share Document