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Time‐frequency spectral analysis of inspiratory motor discharges during spontaneous and hypoxia‐facilitated augmented (sigh) bursts in anesthetized adult C57BL/6 mice in vivo
Author(s) -
Kiridly Daniel N,
Spiegel Evan T,
Warren Kelly A,
Solomon Irene C
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a781
Subject(s) - physics , hypoxia (environmental) , breathing , basal (medicine) , astrophysics , medicine , biology , anatomy , oxygen , quantum mechanics , insulin
Previous work from our laboratory has demonstrated the time‐varying (TV) spectral characteristics of eupneic breathing in adult C57BL/6 mice using the Smoothed pseudo‐Wigner‐Ville distribution (SPWD) method. While temporal (e.g., timing, patterning) differences between the eupneic and augmented (Aug) burst (sigh) patterns have been characterized, the underlying TV spectral characteristics associated with Aug bursts have yet to be examined. Therefore, SPWD analyses were performed on diaphragm EMG bursts recorded from spontaneously breathing urethane‐anesthetized adult C57BL/6 mice (n=11) in vivo during eupneic breathing and both spontaneous and hypoxia‐facilitated Aug bursts. As previously described, the TV spectrum of eupnea exhibited multiple bursts of spectral activity in the frequency ranges associated with medium (MFO), high (HFO), and upper high (UHFO) frequency oscillations. During Aug bursts, power in the UHFO range was enhanced (P<0.001), spectral duration was reduced, and spectral power was more concentrated; however, there were no shifts in the dominant spectral frequencies. Comparisons between burst pair segments consisting of either two bursts under basal spontaneous (n=159 pairs) or hypoxic (n=42) conditions or an Aug burst and its immediately preceding burst (n=53 spontaneous; n=18 hypoxia‐facilitated) revealed that the Aug bursts exhibited increased power relative to the preceding burst (P<0.001), and that this increase in power was more enhanced during the spontaneous Aug bursts as compared to the hypoxia‐facilitated Aug bursts (58% spontaneous vs. 67% hypoxia‐facilitated). These data support the concept that Aug bursts reflect reconfiguration of the inspiratory neural network. Supported by NS045321