Spinal projections from the lower brain stem in the cat as demonstrated by the horseradish peroxidase technique. I. Origins of the reticulospinal tracts and their funicular trajectories

摘要: Abstract Using a retrograde tracer technique with horseradish peroxidase (HRP) attempts were made to determine the origins of reticulospinal tracts and their funicular trajectories. Reticulospinal originating from mesencephalic reticular formation (RF) composed of: (1) descending projections arising cluster cells located just lateral periaqueductal gray that course in anterior funiculus (AF) ventral part (LF) ipsilateral predominance; (2) dorsal brachium conjunctivum LF. Origins ponpine n. reticularis pontis oralis (Poo) have been divided into three parts: medial one-third; middle; (3) ventrolateral. The axons descend ipsilaterally via AF, while ventrolateral Poo give rise diffuse AF middle has further subdivided into: gives spinal (VLF); ventral, particularly its upper part, whose bilaterally DLF. caudalis (Poc) could be medial; dorsolateral; Poc is source nucleus contralateral dorsolateral appears diffusely LF, but DLF predominance. gigantocellularis (Gc) was found main medullary magnocellularis (Mc) major fibers coursing VLF. most Mc descends together lateralis Meessen Olszewski It also paramedianus pass both LF predominance, dorsalis ventralis