Mechanoreceptor Cells of the Lamprey Spinal Cord: Direct Connections with Identified Segmental Neurons
The organization of primary segmental afferents which act on motoneurons in various species of vertebrates is not quite clear. As is known, direct connections with motoneurons in mammals are formed by afferents from intrafusal muscle fibers. As to the lower (aquatic) vertebrates, they lack muscle spindles (Bone, 1964). Therefore the suggestion was made that they can have no direct connection between the primary afferents and motoneurons. Thus, only polysynaptic responses of motoneurons were described in bony fishes under dorsal root stimulation (Bando, 1975). However, monosynaptic responses were obtained in rays (Leonard et al., 1978) and lampreys (Birnberger and Rovainen, 1971).
KeywordsPrimary Afferents Anterograde Transport White Muscle Fiber Dorsal Cell Intrafusal Muscle Fiber
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- Shapovalov, A.I., and Batueva, I.V., 1984, Interaction between segmental primary afferents and motoneurons in the spinal cord of the lamprey, Sechenov Physiol. J. USSR, 70, 1178–1188.Google Scholar