Spatiotemporal regulation of the cough motor pattern

Abstract

The purpose of this study was to identify the spatiotemporal determinants of the cough motor pattern. We speculated that the spatial and temporal characteristics of the cough motor pattern would be regulated separately. Electromyograms (EMG) of abdominal muscles (ABD, rectus abdominis or transversus abdominis), and parasternal muscles (PS) were recorded in anesthetized cats. Repetitive coughing was produced by mechanical stimulation of the lumen of the intrathoracic trachea. Cough inspiratory (CTI) and expiratory (CTE) durations were obtained from the PS EMG. The ABD EMG burst was confined to the early part of CTE and was followed by a quiescent period of varying duration. As such, CTE was divided into two segments with CTE1 defined as the duration of the ABD EMG burst and CTE2 defined as the period of little or no EMG activity in the ABD EMG. Total cough cycle duration (CTTOT) was strongly correlated with CTE2 (r2>0.8), weakly correlated with CTI (r2<0.3), and not correlated with CTE1 (r2<0.2). There was no significant relationship between CTI and CTE1 or CTE2. The magnitudes of inspiratory and expiratory motor drive during cough were only weakly correlated with each other (r2<0.36) and were not correlated with the duration of any phase of cough. The results support: a) separate regulation of CTI and CTE, b) two distinct subphases of CTE (CTE1 and CTE2), c) the duration of CTE2 is a primary determinant of CTTOT, and d) separate regulation of the magnitude and temporal features of the cough motor pattern.

The course of lung inflation alters the central pattern of tracheobronchial cough in cat—The evidence for volume feedback during cough

“…These results are consistent with the fact that CT E is the largest governing component of CTtot (Wang et al, 2009). However, when the ventilator provided tidal volume there was a reduction in the CT E - CTtot relationship and surprisingly there was an increase of CT I - CT E1 relationship.…”

“…There were weak correlations between inspiratory and expiratory cough efforts, and very weak correlations between the cough volume, CT I , and CT E as were previously published (Bolser and Davenport, 2000; Wang et al, 2009). Weak correlations were also found in coughs, with fast cough volume delivered by ventilator, between CT E1 and amplitudes of DIA and ABD EMG, while no such relation was seen for other conditions (Table 3).…”

“…Eupneic volume-timing relationships primarily attributed to PSR’s (longer phase duration at lower lung volume; Zechman et al, 1976; Davenport et al, 1981), are not present in tracheobronchial cough in cat (Bolser and Davenport, 2000). Additionally, there are minimal correlations between cough amplitudes and phase durations in pentobarbital-anesthetized cats (Wang et al, 2009). These data suggest that PSR discharge does not significantly affect cough.…”

Variability of the Pharyngeal Phase of Swallow in the Cat

“…This model also benefits from a high degree of knowledge of the brainstem control system for behaviors involving respiratory muscles [29], [33]–[37] We hypothesized that spatiotemporal control of pharyngeal muscles involved in hyoid elevation and pharyngeal constriction would be modifiable based on stimulus modality.…”

GABA-ergic neurotransmission in the nucleus of the solitary tract modulates cough in the cat

“…A reduction in vagal afferent input (unilateral vagal cooling) resulted in a marked prolongation of CTE and CTE1 (Simera et al, 2016). The determining component of CTtot is CTE2 (Wang et al, 2009; Pitts et al, 2016). Our microinjections altered CTE2 very little (Table 1).…”