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Synchronous synaptic input to respiratory muscle motoneurons of tongue and inspiratory intercostal muscles.
Author(s) -
Rice Amber D,
Fregosi Ralph F
Publication year - 2009
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.23.1_supplement.783.9
Subject(s) - genioglossus , intercostal muscle , motor unit , tongue , motor neuron , pharyngeal muscles , anatomy , muscles of respiration , respiratory system , medicine , neuroscience , biology , pharynx , spinal cord , pathology
Short time scale, synchronous firing of two or more motor units, within or between muscles, is thought to be due to common input from the same presynaptic neuron. The extent of synchronous input can be quantified with cross‐correlation analysis of simultaneously recorded motoneurons or motor units. We examined the prevalence of synchronous discharge of motor units within genioglossus (tongue protrudor muscle), hyoglossus (tongue retractor muscle) and inspiratory intercostal muscles. 28 pairs of single motor unit potentials were recorded in urethane‐anesthetized rats, and cross correlation analysis was performed on each pair. Long‐time scale oscillations were found in all 28 pairs of simultaneously recorded motor units, reflecting shared input from the respiratory central pattern generator (CPG). 6/12 pairs of ipsilateral hyoglossus units, 2/3 pairs of ipsilateral genioglossus motor units and 6/13 pairs of ipsilateral intercostal motor units showed short time scale peaks in the cross correlation histogram. However, the strength of the correlation between pairs of intercostal motor units was higher than that for tongue muscle motor units. Tongue muscles appear to have more complex presynaptic circuitry than intercostal muscles. Supported by the NIDCD.