Spinal projection to the dorsolateral nucleus of the caudal basilar pons in the cat

Abstract

In the cat, a spinal projection to a restricted area of the basilar pontine grey has been revealed with use of an anterograde degeneration technique (Fink‐Heimer). The area was ipsilateral to the spinal lesion, restricted to the far caudal limit of the pons, and included the dorsal and the dorsolateral subdivisions of the pontine nuclei (PN). Comparisons following high cervical, midthoracic and upper lumbar spinal lesions did not reveal any somatotopic organization. Only a few spinopontine fibers had origins below segmental level L4. Lesions of various quadrants of the cord indicated that the spinopontine fibers ascendede through the dorsolateral funiculus, and not through either the dorsal or the verntal funiculi. Comparison with the degeneration effects of cerebral cortical lesions showed that the spinal projection from the first sensorimotor and second somatosensory cortices. In the rat no comparable spinopontine projection was found. It is suggested that the spinopontine pathway migh forward information to the cerebellum from visceral sensory receptors or perhaps from pools of spinal interneurons.