Response of slowly adapting pulmonary stretch receptors to reduced lung compliance

1991 ◽  
Vol 71 (2) ◽  
pp. 425-431 ◽  
Author(s):  
J. Yu ◽  
T. E. Pisarri ◽  
J. C. Coleridge ◽  
H. M. Coleridge
Keyword(s):  
Steady State ◽  
Tidal Volume ◽  
Time Constant ◽  
Transpulmonary Pressure ◽  
Lung Compliance ◽  
Steady State Response ◽  
Positive End Expiratory Pressure ◽  
State Response ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors

We examined the steady-state response of slowly adapting pulmonary stretch receptors (SAPSRs) to reduced lung compliance in open-chest cats with lungs ventilated at eupneic rate and tidal volume (VT) and with a positive end-expiratory pressure (PEEP) of 3–4 cmH2O. Transient removal of PEEP decreased compliance by approximately 30% and increased transpulmonary pressure (Ptp) by 1–2.5 cmH2O. Reduction of compliance significantly decreased SAPSR discharge in deflation and caused a small increase in discharge at the peak of inflation; it had little effect on discharge averaged over the ventilatory cycle. Increasing VT to produce a comparable increase in Ptp significantly increased peak discharge. Thus unlike rapidly adapting receptors, whose discharge is increased more effectively by reduced compliance than by increased VT, SAPSRs are stimulated by increased VT but not by reduced compliance. We speculate that the most consistent effect of reduced compliance on SAPSRs (the decrease in deflation discharge) was due to the decreased time constant for deflation in the stiffer lung. This alteration in firing may contribute to the tachypnea evoked as the lungs become stiffer.

Effects of pulmonary air embolism on discharge of slowly adapting pulmonary stretch receptors

1994 ◽  
Vol 76 (1) ◽  
pp. 97-103 ◽  
Author(s):  
B. P. Lee ◽  
H. F. Chen ◽  
F. C. Hsu ◽  
T. B. Kuo ◽  
M. H. Yang
Keyword(s):  
Fiber Type ◽  
Air Embolism ◽  
Transpulmonary Pressure ◽  
Lung Compliance ◽  
Group I ◽  
Airway Collapse ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Close Relationship ◽  
Dynamic Lung Compliance

Pulmonary air embolism (PAE) usually causes small-airway collapse. Local transpulmonary pressure (Ptr) is thought to be closely associated with the activity of slowly adapting pulmonary stretch receptors (SAPSRs). To test whether discharge of SAPSRs located distal to collapsed airways is closely related to the overall Ptr, we studied 65 SAPSRs in anesthetized paralyzed open-chest dogs that were ventilated at constant tidal volume and frequency. PAE increased both Ptr and total pulmonary resistance but decreased dynamic lung compliance. Three groups of SAPSRs were identified on the basis of their locations in intrapulmonary airways. Group I had 29 SAPSRs located in airways < 1 mm in diameter. Group II had 10 SAPSRs that were found in intrapulmonary airways between 1 and 2 mm in diameter. PAE decreased the activity of 31 of the 39 SAPSRs in these two groups. Their activity during PAE was not related to Ptr. The 26 SAPSRs in group III were in airways > 2 mm in diameter. PAE increased the peak firing rate of 18 of these receptors, and there was a close relationship between the discharge frequency of these SAPSRs and the Ptr during PAE. In groups I and II, the dissociation between Ptr and SAPSR activity during PAE may have been caused by peripheral airway collapse. Activity of central fibers was blocked at higher temperatures than activity of peripheral fibers. We suggest that the response of a SAPSR to PAE depends on the location of the receptor within the lungs, and we speculate that threshold and fiber type are also related to location.

Motion sensitivity in the nucleus of the basal optic root of the pigeon

1994 ◽  
Vol 71 (4) ◽  
pp. 1559-1573 ◽  
Author(s):  
F. Wolf-Oberhollenzer ◽  
K. Kirschfeld
Keyword(s):  
Steady State ◽  
Time Constant ◽  
Temporal Frequency ◽  
State Level ◽  
Sine Wave ◽  
Maximal Response ◽  
Steady State Response ◽  
State Response ◽  
Sine Wave Gratings ◽  
Basic Version

1. Single-unit responses to large-field movement (angular velocity, w = 0.25-42 degrees/s) of sine-wave gratings of different spatial wavelength (lambda = 5.2-41 degrees) and contrast have been recorded in the nucleus of the basal optic root (nBOR) of the accessory optic system (AOS) of the pigeon. 2. The steady-state response to moving sine-wave gratings increases with increasing contrast to reach a saturation level at 25%. 3. Generally the steady-state responses of the cells passed through a maximum when stimulated at various velocities. In 12 of the 15 cells tested with six different velocities and four different spatial wavelengths, the location of the response maximum on the velocity scale depended on the spatial wavelength (lambda) used. That is, in these cells the response depends on the temporal frequency (tf = w/lambda) of the stimulus and not on its velocity alone. This is in agreement with the prediction of the theory of motion detection according to the basic version of the correlation scheme. 4. The temporal frequency for maximal response of individual cells shifts to higher values when the contrast of the sine-wave gratings is reduced to 5%. 5. The steady-state response of 16 of the recorded directional selective cells (53) is modulated with the temporal frequency of the stimulus, regardless of the phase of the grating at the beginning of its movement. 6. In phasic-tonically responding cells, the phasic response peak decays to the steady-state level with a time constant that becomes shorter as the temporal frequency of the stimulus increases. 7. The basic version of the correlation scheme includes only the time constant of one low-pass filter. Therefore the phasic response is expected to decay to the steady-state level with one and the same time constant, and the position of the maximal response on the temporal frequency scale should not be influenced by a change of pattern contrast. According to the model, phase-dependent modulations of the steady-state response should occur only when the spatial wavelength of the stimulus pattern is large compared with the sampling base of the underlying detector. Consequently the results given in points 4-6 cannot be described by a basic version of the correlation scheme.

The Auditory Steady-State Response: Full-Term and Premature Neonates

2002 ◽  
Vol 13 (05) ◽  
pp. 260-269 ◽  
Author(s):  
Barbara Cone-Wesson ◽  
John Parker ◽  
Nina Swiderski ◽  
Field Rickards
Keyword(s):  
Steady State ◽  
Premature Infants ◽  
Modulation Frequency ◽  
Otoacoustic Emission ◽  
Full Term ◽  
Steady State Response ◽  
Pass Rates ◽  
Term Infants ◽  
State Response ◽  
Auditory Steady State Response

Two studies were aimed at developing the auditory steady-state response (ASSR) for universal newborn hearing screening. First, neonates who had passed auditory brainstem response, transient evoked otoacoustic emission, and distortion-product otoacoustic emission tests were also tested with ASSRs using modulated tones that varied in frequency and level. Pass rates were highest (> 90%) for amplitude-modulated tones presented at levels ≥ 69 dB SPL. The effect of modulation frequency on ASSR for 500- and 2000-Hz tones was evaluated in full-term and premature infants in the second study. Full-term infants had higher pass rates for 2000-Hz tones amplitude modulated at 74 to 106 Hz compared with pass rates for a 500-Hz tone modulated at 58 to 90 Hz. Premature infants had lower pass rates than full-term infants for both carrier frequencies. Systematic investigation of ASSR threshold and the effect of modulation frequency in neonates is needed to adapt the technique for screening.

scholarly journals Steady State Response of Linear Time Invariant Systems Modeledby Multibond Graphs

2021 ◽  
Vol 11 (4) ◽  
pp. 1717
Author(s):  
Gilberto Gonzalez Avalos ◽  
Noe Barrera Gallegos ◽  
Gerardo Ayala-Jaimes ◽  
Aaron Padilla Garcia
Keyword(s):  
Steady State ◽  
Linear Time ◽  
Direct Determination ◽  
The State ◽  
Steady State Response ◽  
State Variables ◽  
Linear Time Invariant ◽  
State Response ◽  
Time Invariant

The direct determination of the steady state response for linear time invariant (LTI) systems modeled by multibond graphs is presented. Firstly, a multiport junction structure of a multibond graph in an integral causality assignment (MBGI) to get the state space of the system is introduced. By assigning a derivative causality to the multiport storage elements, the multibond graph in a derivative causality (MBGD) is proposed. Based on this MBGD, a theorem to obtain the steady state response is presented. Two case studies to get the steady state of the state variables are applied. Both cases are modeled by multibond graphs, and the symbolic determination of the steady state is obtained. The simulation results using the 20-SIM software are numerically verified.

Decreased Gamma Auditory Steady-State Response Is Associated With Impaired Real-World Functioning in Unmedicated Patients at Clinical High Risk for Psychosis

2020 ◽  
pp. 155005942098270
Author(s):  
Sarah Ahmed ◽  
Jennifer R. Lepock ◽  
Romina Mizrahi ◽  
R. Michael Bagby ◽  
Cory J. Gerritsen ◽  
...  
Keyword(s):  
Steady State ◽  
High Risk ◽  
Functional Impairment ◽  
Real World ◽  
Steady State Response ◽  
Clinical High Risk ◽  
State Response ◽  
Auditory Steady State Response ◽  
Gamma Synchrony ◽  
40 Hz

Aim Deficits in synchronous, gamma-frequency neural oscillations may contribute to schizophrenia patients’ real-world functional impairment and can be measured electroencephalographically using the auditory steady-state response (ASSR). Gamma ASSR deficits have been reported in schizophrenia patients and individuals at clinical high risk (CHR) for developing psychosis. We hypothesized that, in CHR patients, gamma ASSR would correlate with real-world functioning, consistent with a role for gamma synchrony deficits in functional impairment. Methods A total of 35 CHR patients rated on Global Functioning: Social and Role scales had EEG recorded while listening to 1-ms, 93-dB clicks presented at 40 Hz in 500-ms trains, in response to which 40-Hz evoked power and intertrial phase-locking factor (PLF) were measured. Results In CHR patients, lower 40-Hz PLF correlated with lower social functioning. Conclusions Gamma synchrony deficits may be a biomarker of real-world impairment at early stages of the schizophrenia disease trajectory.

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