The structure of the brainstem and cervical spinal cord in lungless salamanders (family plethodontidae) and its relation to feeding

We present an HRP study of the sensory tracts and motor nuclei associated with feeding (especially use of the tongue) in plethodontid salamanders (mainly Batrachoseps attenuatus, Bolitoglossa subpalmata, Desmognathus ochrophaeus, Eurycea bislineata, and Plethodon jordani). The nerves studied are VII (ramus hyomandibularis only), IX, X, XI, the first spinal nerve (hypoglossus), and the second spinal nerve. Two types of sensory projections are universally found in the brainstem: superficial somatosensory projections of VII, IX, and X, and deeper visceral sensory projections of IX and X to the fasciculus solitarius. The first spinal nerve and the spinal accessory nerve (XI) have no sensory projections, but the second spinal nerve has typical projections along the dorsal funiculus of the spinal cord.

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