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Distributed Networks of Medullary Tonic Expiratory Neurons Regulate Cough Motor Drive
Author(s) -
Shen Tabitha Y.,
Morris Kendall F.,
Baekey David M.,
Musselwhite M. Nicholas,
Segers Lauren S.,
Nuding Sarah,
Rose Melanie J.,
Lindsey Bruce G.,
Bolser Donald C.
Publication year - 2017
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.31.1_supplement.1054.8
Subject(s) - tonic (physiology) , neuroscience , medulla oblongata , excitatory postsynaptic potential , medulla , spinal cord , control of respiration , medicine , respiratory system , anatomy , biology , central nervous system , inhibitory postsynaptic potential
Recently, we showed that ventral medullary tonic E neurons participate in regulatory networks that control respiratory network excitability in response to alterations in chemical drive. The objective of this study was to determine the response patterns during cough of medullary neurons with continuous discharge during the breathing cycle that increased in the expiratory phase (tonic E). We hypothesized that dorsal and ventral medullary tonic E neurons would have activity patterns during coughing consistent with participation in the neurogenesis of this behavior. Further, we speculated that these neurons would participate in functionally‐identified neuronal circuits that regulate the excitability of cranial and spinal motor pathways to respiratory muscles. Using multiple electrode arrays, we recorded from many neurons simultaneously in the regions of the nucleus of the tractus solitarius (dorsal medullary), raphe nuclei, and ventral respiratory column (VRC) in 26 decerebrated, paralyzed, and artificially ventilated cats. A total of 106 tonic E neurons were recorded. During fictive cough, the discharge rates of 42 neurons increased, 21 decreased, and 43 did not change. Cross correlation analysis of simultaneously recorded dorsal and ventral medullary neurons revealed evidence for: a) circuits composed of tonic E neurons that excite one another and provide excitatory drive to expiratory laryngeal premotor and motoneurons, b) evidence for shaping of laryngeal motor discharge by suppression of tonic E neurons by phasic E decrementing neurons, and c) networks of cough‐responsive tonic E and non‐breathing modulated neurons that modulated the activities of recruited cough inspiratory neurons in the dorsal medulla and recruited cough expiratory neurons in the caudal VRC. The results support an important role of dorsal and ventral medullary tonic E neurons in controlling the excitability of cranial and spinal motoneurons that produce cough. Support or Funding Information NIH HL 103415 and 1OT20D001983