排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
Louis Laviolette Marie-Cécile Niérat Anna L. Hudson Mathieu Raux étienne Allard Thomas Similowski 《PloS one》2013,8(4)
Introduction
In humans, cortical mechanisms can interfere with autonomic breathing. Respiratory-related activation of the supplementary motor area (SMA) has been documented during voluntary breathing and in response to inspiratory constraints. The SMA could therefore participate in the increased resting state of the respiratory motor system during wake (i.e. "wakefulness drive to breathe").Methods
The SMA was conditioned by continuous theta burst magnetic stimulation (cTBS, inhibitory) and 5 Hz conventional rTMS (5 Hz, excitatory). The ensuing effects were described in terms of the diaphragm motor evoked response (DiMEPs) to single-pulse transcranial magnetic stimulation over the motor cortex. DiMEPs were recorded at baseline, and at 3 time-points ("post1", "post2", "post3") up to 15 minutes following conditioning of the SMA.Results
cTBS reduced the amplitude of DiMEPs from 327.5±159.8 µV at baseline to 243.3±118.7 µV, 217.8±102.9 µV and 240.6±123.9 µV at post 1, post 2 and post 3, respectively (F = 6.341, p = 0.002). 5 Hz conditioning increased the amplitude of DiMEPs from 184.7±96.5 µV at baseline to 270.7±135.4 µV at post 3 (F = 4.844, p = 0.009).Conclusions
The corticospinal pathway to the diaphragm can be modulated in both directions by conditioning the SMA. This suggests that the baseline respiratory activity of the SMA represents an equipoise from which it is possible to move in either direction. The resting corticofugal outflow from the SMA to phrenic motoneurones that this study evidences could putatively contribute to the wakefulness drive to breathe. 相似文献2.
A phylogenetic hypothesis for the origin of hiccough 总被引:8,自引:0,他引:8
Straus C Vasilakos K Wilson RJ Oshima T Zelter M Derenne JP Similowski T Whitelaw WA 《BioEssays : news and reviews in molecular, cellular and developmental biology》2003,25(2):182-188
The occurrence of hiccoughs (hiccups) is very widespread and yet their neuronal origin and physiological significance are still unresolved. Several hypotheses have been proposed. Here we consider a phylogenetic perspective, starting from the concept that the ventilatory central pattern generator of lower vertebrates provides the base upon which central pattern generators of higher vertebrates develop. Hiccoughs are characterized by glottal closure during inspiration and by early development in relation to lung ventilation. They are inhibited when the concentration of inhaled CO(2) is increased and they can be abolished by the drug baclofen (an agonist of the GABA(B) receptor). These properties are shared by ventilatory motor patterns of lower vertebrates, leading to the hypothesis that hiccough is the expression of archaic motor patterns and particularly the motor pattern of gill ventilation in bimodal breathers such as most frogs. A circuit that can generate hiccoughs may persist in mammals because it has permitted the development of pattern generators for other useful functions of the pharynx and chest wall muscles, such as suckling or eupneic breathing. 相似文献
3.
Eric Verin Christian Straus Alexandre Demoule Philippe Mialon Jean-Philippe Derenne Thomas Similowski 《Journal of applied physiology》2002,92(3):967-974
Phrenic nerve stimulation, electrical (ES) or from cervical magnetic stimulation (CMS), allows one to assess the diaphragm contractile properties and the conduction time of the phrenic nerve (PNCT) through recording of an electromyographic response, traditionally by using surface electrodes. Because of the coactivation of extradiaphragmatic muscles, signal contamination can jeopardize the determination of surface PNCTs. To address this, we compared PNCTs with ES and CMS from surface and needle diaphragm electrodes in five subjects (10 phrenic nerves). At a modified recording site, lower and more anterior than usual (lowest accessible intercostal space, costochondral junction) with electrodes 2 cm apart, surface and needle PNCTs were similar (CMS: 6.0 +/- 0.25 ms surface vs. 6.2 +/- 0.13 ms needle, not significant). Electrodes recording the activity of the most likely sources of signal contamination, i.e., the serratus anterior and pectoralis major, showed distinct responses from that of the diaphragm, their earlier occurrence strongly arguing against contamination. With ES and CMS, apparently uncontaminated signals could be consistently recorded from surface electrodes. 相似文献
4.
C Straus C Locher M Zelter J-P Derenne T Similowski 《Journal of applied physiology》2004,97(3):902-912
The human respiratory neural drive has an automatic component (bulbospinal pathway) and a volitional component (corticospinal pathway). The aim of this study was to assess the effects of a hypercapnia-induced increase in the automatic respiratory drive on the function of the diaphragmatic corticospinal pathway as independently as possible of any other influence. Thirteen healthy volunteers breathed room air and then 5 and 7% hyperoxic CO2. Cervical (cms) and transcranial (tms) magnetic stimulations were performed during early inspiration and expiration. Transdiaphragmatic pressure (Pdi) and surface electromyogram of the diaphragm (DiEMG) and of the abductor pollicis brevis (apbEMG) were recorded in response to cms and tms. During inspiration, Pdi,cms was unaffected by CO2, but Pdi,tms increased significantly with 7% CO2. During expiration, Pdi,cms was significantly reduced by CO2, whereas Pdi,tms was preserved. DiEMG,tms latencies decreased significantly during early inspiration and expiration (air vs. 5% CO2 and air vs. 7% CO2). DiEMG,tms amplitude increased significantly in response to early expiration-tms (air vs. 5% CO2 and air vs. 7% CO2) but not in response to early inspiration-tms. DiEMG,cms latencies and amplitudes were not affected by CO2 whereas 7% CO2 significantly increased the apbEMG,cms latency. The apbEMG,tms vs. apbEMG,cms latency difference was unaffected by CO2. In conclusion, increasing the automatic drive to breathe facilitates the response of the diaphragm to tms, during both inspiration and expiration. This could allow the corticospinal drive to breathe to keep the capacity to modulate respiration in conditions under which the automatic respiratory control is stimulated. 相似文献
5.
Straus C Samara Z Fiamma MN Bautin N Ranohavimparany A Le Coz P Golmard JL Darré P Zelter M Poon CS Similowski T 《American journal of physiology. Regulatory, integrative and comparative physiology》2011,300(5):R1163-R1174
Human ventilation at rest exhibits mathematical chaos-like complexity that can be described as long-term unpredictability mediated (in whole or in part) by some low-dimensional nonlinear deterministic process. Although various physiological and pathological situations can affect respiratory complexity, the underlying mechanisms remain incompletely elucidated. If such chaos-like complexity is an intrinsic property of central respiratory generators, it should appear or increase when these structures mature or are stimulated. To test this hypothesis, we employed the isolated tadpole brainstem model [Rana (Pelophylax) esculenta] and recorded the neural respiratory output (buccal and lung rhythms) of pre- (n = 8) and postmetamorphic tadpoles (n = 8), at physiologic (7.8) and acidic pH (7.4). We analyzed the root mean square of the cranial nerve V or VII neurograms. Development and acidosis had no effect on buccal period. Lung frequency increased with development (P < 0.0001). It also increased with acidosis, but in postmetamorphic tadpoles only (P < 0.05). The noise-titration technique evidenced low-dimensional nonlinearities in all the postmetamorphic brainstems, at both pH. Chaos-like complexity, assessed through the noise limit, increased from pH 7.8 to pH 7.4 (P < 0.01). In contrast, linear models best fitted the ventilatory rhythm in all but one of the premetamorphic preparations at pH 7.8 (P < 0.005 vs. postmetamorphic) and in four at pH 7.4 (not significant vs. postmetamorphic). Therefore, in a lower vertebrate model, the brainstem respiratory central rhythm generator accounts for ventilatory chaos-like complexity, especially in the postmetamorphic stage and at low pH. According to the ventilatory generators homology theory, this may also be the case in mammals. 相似文献
6.
Lysandre Tremoureux Mathieu Raux Anna L. Hudson Anja Ranohavimparany Christian Straus Thomas Similowski 《PloS one》2014,9(1)
Background
Congenital central hypoventilation syndrome (CCHS) is a rare neuro-respiratory disorder associated with mutations of the PHOX2B gene. Patients with this disease experience severe hypoventilation during sleep and are consequently ventilator-dependent. However, they breathe almost normally while awake, indicating the existence of cortical mechanisms compensating for the deficient brainstem generation of automatic breathing. Current evidence indicates that the supplementary motor area plays an important role in modulating ventilation in awake normal humans. We hypothesized that the wake-related maintenance of spontaneous breathing in patients with CCHS could involve supplementary motor area.Methods
We studied 7 CCHS patients (5 women; age: 20–30; BMI: 22.1±4 kg.m−2) during resting breathing and during exposure to carbon dioxide and inspiratory mechanical constraints. They were compared with 8 healthy individuals. Segments of electroencephalographic tracings were selected according to ventilatory flow signal, from 2.5 seconds to 1.5 seconds after the onset of inspiration. After artefact rejection, 80 or more such segments were ensemble averaged. A slow upward shift of the EEG signal starting between 2 and 0.5 s before inspiration (pre-inspiratory potential) was considered suggestive of supplementary motor area activation.Results
In the control group, pre-inspiratory potentials were generally absent during resting breathing and carbon dioxide stimulation, and consistently identified in the presence of inspiratory constraints (expected). In CCHS patients, pre-inspiratory potentials were systematically identified in all study conditions, including resting breathing. They were therefore significantly more frequent than in controls.Conclusions
This study provides a neurophysiological substrate to the wakefulness drive to breathe that is characteristic of CCHS and suggests that the supplementary motor area contributes to this phenomenon. Whether or not this “cortical breathing” can be taken advantage of therapeutically, or has clinical consequences (like competition with attentional resources) remains to be determined. 相似文献7.
8.
Chrystèle Locher Mathieu Raux Marie-Noelle Fiamma Capucine Morélot-Panzini Marc Zelter Jean-Philippe Derenne Thomas Similowski Christian Straus 《BMC physiology》2006,6(1):7-9
Background
Breathing in humans is dually controlled for metabolic (brainstem commands) and behavioral purposes (suprapontine commands) with reciprocal modulation through spinal integration. Whereas the ventilatory response to chemical stimuli arises from the brainstem, the compensation of mechanical loads in awake humans is thought to involve suprapontine mechanisms. The aim of this study was to test this hypothesis by examining the effects of inspiratory resistive loading on the response of the diaphragm to transcranial magnetic stimulation. 相似文献9.
Validation of surface recordings of the diaphragm response to transcranial magnetic stimulation in humans. 总被引:4,自引:0,他引:4
Alexandre Demoule Eric Verin Chrystèle Locher Jean-Philippe Derenne Thomas Similowski 《Journal of applied physiology》2003,94(2):453-461
The integrity of the central efferent motor pathways to the diaphragm can be assessed by using transcranial magnetic stimulation to measure the latency of the corresponding motor evoked potentials with surface electrodes. Because transcranial magnetic stimulation does not activate the diaphragm alone, signal contamination is a potential problem. To evaluate this issue, surface diaphragmatic motor-evoked potential latencies were compared with latencies recorded from diaphragm needle in 9 healthy volunteers. Surface latencies of muscles likely to contaminate the diaphragm signals (serratus anterior, pectoralis major, and tranversus abdominis) were also recorded. The latencies in response to nonfocal transcranial stimulation from surface electrodes were not significantly different from the needle ones (17 +/- 1.3 vs. 17.2 +/- 1.1 ms, respectively) but were significantly different from the latencies of the other muscles. In two cases, signal contamination appeared likely (serratus anterior in 1 case, abdominal muscles in 1 case). It is possible to reliably measure the latency of the diaphragm response to transcranial magnetic stimulation with adequately positioned surface electrodes. 相似文献
10.
Philippe Devillier Eric Garrigue Guillaume D’Auzers Nicolas Monjotin Thomas Similowski Thierry Clerc 《Respiratory research》2015,16(1)