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Identification and connections of inspiratory premotor neurons in songbirds and budgerigar
Author(s) -
Reinke H.,
Wild J.M.
Publication year - 1998
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19980209)391:2<147::aid-cne1>3.0.co;2-2
Subject(s) - anatomy , brainstem , spinal cord , biotinylated dextran amine , nucleus , medulla oblongata , neuroscience , medulla , spinothalamic tract , lateral funiculus , hypoglossal nucleus , rostral ventrolateral medulla , biology , central nervous system , biochemistry , receptor , nociception
Recordings of extracellular unit activity in the ventrolateral medulla and of electyromyographic activity in either the M. scalenus, a principal inspiratory muscle, or the abdominal expiratory muscles, were used to identify inspiratory related (IR) neurons. IR neurons extended from levels caudal to the obex through the caudal level of the descending vestibular nucleus. This distribution was found to correspond to that of a subset of cells retrogradely labeled from injections of neuronal tracers into the upper thoracic spinal cord, where motoneurons innervating the M. scalenus were located by retrograde transport. Injections of biotinylated dextran amine at the recording sites resulted in projections to the spinal cord and brainstem. Bulbospinal axons traveled in the lateral funiculus, predominantly contralaterally, and terminated in relation to the dendrites and cell bodies of motoneurons innervating the M. scalenus. Brainstem nuclei receiving projections from injections at IR loci included the retroambigualis, tracheosyringeal motor nucleus, ventrolateral nucleus of the rostral medulla, infra‐olivaris superior, ventrolateral parabrachial nucleus, and the dorsomedial nucleus of the intercollicular complex. In the finches, there were also bilateral projections to nucleus uvaeformis of the posterior thalamus. The spinal and brainstem projections are similar to those found in pigeon (Reinke and Wild, [1997] J. Comp. Neurol. 379:347–362), and probably mediate the intricate coordination of the vocal (syringeal) and respiratory systems for the control of vocalization. The distribution of IR neurons in birds is similar to that of the rostral ventral respiratory group (rVRG) in mammals. J. Comp. Neurol. 391:147–163, 1998. © 1998 Wiley‐Liss, Inc.