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Spectral Dynamics Underlying Hypoglossal Motor Discharge In The Transverse Medullary Slice Preparation From Neonatal Rat
Author(s) -
Solomon Irene C,
Shafer Geoffrey O,
Wilson Christopher G
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.a782
Subject(s) - spectral analysis , hypoglossal nerve , chemistry , slice preparation , rhythm , nuclear magnetic resonance , physics , medicine , tongue , pathology , in vitro , biochemistry , spectroscopy , quantum mechanics
Fast oscillatory rhythms have been identified in inspiratory‐related discharges, using predominantly time‐invariant (FFT‐based) spectral analysis methods. To identify the dynamic ( i.e. , time‐varying, TV) features underlying these fast rhythmic oscillations, time‐frequency (TF) spectral analysis should be used. Recent work form our laboratory has identified and characterized the TV characteristics of spectral activity in inspiratory bursts in a number of in vivo adult preparations ( e.g. , mouse, rat, piglet, cat); however, the TV nature of spectral activity in the reduced transverse medullary slice preparation remains to be demonstrated. Therefore, TF analysis using a generalized TFR with the smoothed pseudo Wigner‐Ville distribution (SPWD) kernel was performed on hypoglossal nerve discharges recorded from the neonatal rat (P1‐P5, n=20) slice preparation superfused with aCSF containing 3–9 mM KCl. With superfusion of aCSF containing 8–9 mM KCl, the TF spectrum was characterized by multiple bursts of spectral activity between 10–50 Hz, which exhibited an early onset (~5–15% of burst duration (T I )) and persisted for 51.7±3.8% of T I . With lower KCl concentrations (3, 5, and 7 mM), the onset of spectral activity was slightly delayed and the duration of spectral activity was generally prolonged (to ~65% T I ). Regardless of the KCl level, multiple bursts of spectral activity were observed in both individual bursts and ensemble‐averaged bursts. These findings suggest that inspiratory‐phase spectral activity in the reduced respiratory network is highly dynamic and that increased drive (elevated KCl) enhances synchronization. Supported by NS045321 and NS46062 as part of the NSF/NIH CRCNS Program