Dorsal and ventral myotome motoneurons and their input during fictive locomotion in lamprey

摘要: Motoneurons supplying the dorsal and ventral parts of myotome in lamprey are shown to have different morphological characteristics; furthermore, their pattern activation during fictive locomotion may differ considerably. Intracellular recordings from motoneurons were performed an vitro spinal cord-myotome preparation segments rostral fins. The location contracting muscle fibers could be observed directly dissection microscope intracellular stimulation motoneuron. injected with Lucifer Yellow, dye, subsequently reconstructed, sometimes both a horizontal transverse plane. third had dense, fan-like, dendritic tree ramifications near midline. In contrast, more widespread less dense tree, few Some most or part contralateral dendrites crossing commissure ramifying large, reticulospinal Muller fibers. differences morphology indicate that these receive descending inputs. This related need for effective control dorsoventral plane righting steering responses. During elicited isolated cord by bath-applied N-methyl-aspartate, pairs recorded which identified characterized injections Yellow.(ABSTRACT TRUNCATED AT 250 WORDS)