Direct Projections of Omnipause Neurons to Reticulospinal Neurons: A Double-Labeling Light Microscopic Study in the Cat

作者：Grantyn Alexej^*; Kuze Bunya; Brandi Anne Marie; Thomas Marie Annick; Quenech'du Nicole

来源：Journal of Comparative Neurology, 2010, 518(23): 4792-4812.

DOI：10.1002/cne.2488

• pons
• medulla
• spinal cord
• horseradish peroxidase
• biocytin
• reticular formation
• orienting synergies

Omnipause neurons (OPNs) are inhibitory neurons located in the midline region of the caudal pons Their role in gating the discharges of saccade-related burst neurons is well known, but there is no agreement concerning their influence on brainstem neurons that control other muscle groups participating in rapid gaze shifts In the present study, we inquired whether OPNs project directly to pontobulbar reticulospinal neurons (RSNs) in the cat Retrograde transport of horseradish peroxidase from the cervical spinal cord was used to label RSNs and an anterograde tracer (biocytin) was iontophoresed at sites of extracellular recording of the OPN activity Somadendritic characteristics of biocytin-labeled OPNs were largely similar to those obtained previously with intracellular labeling Three-dimensional reconstruction of axonal trajectories and collaterals revealed that projections of OPNs, regarded as a population, are bilateral Their terminals were restricted to the reticular formation and midline structures throughout the rostral bulbar and pontine tegmentum Appositions of synaptic boutons originating from five fully stained OPNs were detected on 38 retrogradely labeled RSNs, each of the OPNs contacting 3-13 cells The numbers of boutons (1-46, mean 11 8) on the RSN somata and proximal dendrites indicate that the anatomical strength of paired OPN-RSN connections is comparable to that of other similarly studied inhibitory neurons in the cat The existence of connections with RSNs supports the hypothesis of a generalized influence of OPNs on

• 出版日期2010-12-1