Descending fibres of the lateral funiculus of the amphibian spinal cord: their course and terminal distribution.

Descending fibres of the lateral funiculus (LF) of the spinal cord have been mapped in the adult bullfrog, Rana catesbeiana. Following large and small lesions of the cervical LF, Nauta preterminal and terminal degeneration staining techniques revealed a large bilateral projection to intermediate regions of the lumbar central grey. Dorsal LF fibres were seen only contralaterally, and ventral fibres mainly ipsilaterally, Medical LF fibre and terminal degeneration occurred bilaterally. Terminal fields of ipsilateral fibres often included the large motoneuron somata situated dorsolaterally in the ventral grey. The smaller contralateral contingent of fibres terminated most often in areas of the central grey dorsal or medial to the motoneuron pool.