Reinke H, Wild J M
Department of Anatomy, School of Medicine, University of Auckland, New Zealand.
J Comp Neurol. 1998 Feb 9;391(2):147-63.
Recordings of extracellular unit activity in the ventrolateral medulla and of electromyographic 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, infraolivaris 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.
通过记录延髓腹外侧的细胞外单位活动以及主要吸气肌斜角肌或腹部呼气肌的肌电图活动，来识别吸气相关（IR）神经元。IR神经元从闩尾侧水平延伸至前庭神经核尾侧水平。发现这种分布与将神经示踪剂注入胸段脊髓上部后逆行标记的一部分细胞的分布相对应，通过逆行运输确定支配斜角肌的运动神经元位于此处。在记录部位注射生物素化葡聚糖胺后，出现了向脊髓和脑干的投射。延髓脊髓轴突在外侧索中走行，主要是对侧走行，并终止于支配斜角肌的运动神经元的树突和胞体附近。接受IR位点注射投射的脑干核包括疑后核、气管鸣管运动核、延髓头端腹外侧核、上橄榄下核、臂旁腹外侧核和顶盖间复合体背内侧核。在雀类中，还有向后丘脑葡萄状核的双侧投射。脊髓和脑干的投射与在鸽子中发现的投射相似（Reinke和Wild，[1997]《比较神经学杂志》379:347 - 362），可能介导了发声（鸣管）和呼吸系统为控制发声而进行的复杂协调。鸟类中IR神经元的分布与哺乳动物的头端腹侧呼吸组（rVRG）相似。
