Patterns of neural and muscular electrical activity in costal and crural portions of the diaphragm

Oyer, Linda M.; Knuth, Susan L.; Ward, D.K.; Bartlett, D.

doi:10.1152/jappl.1989.66.5.2092

Cited by 18 publications

(14 citation statements)

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“…Techniques permitting chronic EMG recordings (Trelease et al, 1982), if adapted to the rat, could be useful for assessment of DIAm function over time, e.g., during assessment of functional recovery following spinal cord injury (Sieck & Mantilla, 2009). Although EMG recordings were performed in the costal DIAm, activity and fiber type composition in costal and crural regions of the DIAm is similar (Oyer et al, 1989; Reid et al, 1992; Sieck, 1988), and thus, EMG activity of the costal region is representative of motor unit activation in the entire DIAm.…”

Section: Discussionmentioning

confidence: 99%

Diaphragm motor unit recruitment in rats

Mantilla

Seven

Zhan

et al. 2010

Respiratory Physiology & Neurobiology

119

268

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We hypothesized that considerable force reserve exists for the diaphragm muscle (DIAm) to generate transdiaphragmatic pressures (Pdi) necessary to sustain ventilation. In rats, we measured Pdi and DIAm EMG activity during different ventilatory (eupnea and hypoxia (10% O2) – hypercapnia (5% CO2)) and non-ventilatory (airway occlusion and sneezing induced by intranasal capsaicin) behaviors. Compared to maximum Pdi (Pdimax - generated by bilateral phrenic nerve stimulation), the Pdi generated during eupnea (21±2%) and hypoxia-hypercapnia (28±4%) were significantly less (P<0.0001) than that generated during airway occlusion (63±4%) and sneezing (94±5%). The Pdi generated during spontaneous sighs was 62±5% of Pdimax. Relative DIAm EMG activity (root mean square [RMS] amplitude) paralleled the changes in Pdi during different ventilatory and non-ventilatory behaviors (r2=0.78; p<0.0001). These results support our hypothesis of a considerable force reserve for the DIAm to accomplish ventilatory behaviors. A model for DIAm motor unit recruitment predicted that ventilatory behaviors would require activation of only fatigue resistant units.

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Section: Discussionmentioning

confidence: 99%

Diaphragm motor unit recruitment in rats

Mantilla

Seven

Zhan

et al. 2010

Respiratory Physiology & Neurobiology

119

268

View full text Add to dashboard Cite

show abstract

“…It is important to note that the activity and fiber type composition in the costal and crural regions of the diaphragm muscle is similar (Oyer et al, 1989; Reid et al, 1992; Sieck, 1988), and thus, it may be possible to implant EMG electrodes in either region and obtain representative recordings of phrenic motor unit activation. In humans, esophageal or laparoscopic intramuscular electrode placement are possible (Beck et al, 2001; Beck et al, 1996, 1998; Hemmerling et al, 2001).…”

Section: Orderly Recruitment Of Motor Unitsmentioning

confidence: 99%

Phrenic motor unit recruitment during ventilatory and non-ventilatory behaviors

Mantilla

Sieck

2011

Respiratory Physiology & Neurobiology

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Phrenic motoneurons are located in the cervical spinal cord and innervate the diaphragm muscle, the main inspiratory muscle in mammals. Similar to other skeletal muscles, phrenic motoneurons and diaphragm muscle fibers form motor units which are the final element of neuromotor control. In addition to their role in sustaining ventilation, phrenic motor units are active in other non-ventilatory behaviors important for airway clearance such as coughing or sneezing. Diaphragm muscle fibers comprise all fiber types and are commonly classified based on expression of contractile proteins including myosin heavy chain isoforms. Although there are differences in contractile and fatigue properties across motor units, there is a matching of properties for the motor neuron and muscle fibers within a motor unit. Motor units are generally recruited in order such that fatigue-resistant motor units are recruited earlier and more often than more fatigable motor units. Thus, in sustaining ventilation, fatigue-resistant motor units are likely required. Based on a series of studies in cats, hamsters and rats, an orderly model of motor unit recruitment was proposed that takes into consideration the maximum forces generated by single type-identified diaphragm muscle fibers as well as the proportion of the different motor unit types. Using this model, eupnea can be accomplished by activation of only slow-twitch diaphragm motor units and only a subset of fast-twitch, fatigue-resistant units. Activation of fast-twitch fatigable motor units only becomes necessary when accomplishing tasks that require greater force generation by the diaphragm muscle, e.g., sneezing and coughing.

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“…Now we report a waveform seen in fetal biomagnetometry recordings that has a temporal frequency and duration consistent with fetal breathing movements. During contractions, the diaphragm is an electrically active region (23-26). We provide evidencethat the biomagnetic signals characterized here are generated by activation of the fetal diaphragm, which we have termed the diaphragmatic magnetomyogram (dMMG).…”

Section: Introductionmentioning

confidence: 99%

Characterization of the fetal diaphragmatic magnetomyogram and the effect of breathing movements on cardiac metrics of rate and variability

Gustafson

Allen

May

2011

Early Human Development

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Breathing movements are one of the earliest fetal motor behaviors to emerge andare ahallmark of fetal well-being. Fetal respiratory sinus arrhythmia (RSA) has been documented but efforts to quantify the influence of breathing on heart rate (HR) and heart rate variability (HRV) are difficult due to the episodic nature of fetal breathing activity. We used a dedicated fetal biomagnetometer to acquire the magnetocardiogram (MCG) between 36-38 weeks gestational age (GA). We identified and characterized a waveform observed in the raw data and independent component decomposition that we attribute to fetal diaphragmatic movements during breathing episodes. RSA and increased high frequency power in a time-frequency analysis of the IBI time-series was observed during fetal breathing periods. Using the diaphragmatic magnetomyogram (dMMG) as a marker, we compared time and frequency domain metrics of heartrate and heart rate variability between breathing and non-breathing epochs. Fetal breathing activity resulted in significantly lower HR, increased high frequency power, greater sympathovagal balance, increased short-term HRV andgreater parasympathetic input relative to non-breathing episodesconfirming the specificity of fetal breathing movements on parasympathetic cardiac influence. No significant differences between breathing and non-breathing epochs were found in two metrics reflecting total HRVor very low, low and intermediate frequency bands. Using the fetal dMMG as a marker, biomagnetometry can help to elucidate the electrophysiologic mechanisms associated with diaphragmatic motor function and may be used to study the longitudinal development of human fetal cardiac autonomic control and breathing activity.

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Patterns of neural and muscular electrical activity in costal and crural portions of the diaphragm

Cited by 18 publications

References 0 publications

Diaphragm motor unit recruitment in rats

Diaphragm motor unit recruitment in rats

Phrenic motor unit recruitment during ventilatory and non-ventilatory behaviors

Characterization of the fetal diaphragmatic magnetomyogram and the effect of breathing movements on cardiac metrics of rate and variability

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