Spinal projections to the dorsal column nuclei in pigeons.

The dorsal column (DC) system was investigated in the pigeon by electrophysiological and anatomical methods. Field potentials recorded from the dorsal column nuclei (DCN) and evoked by electrical stimulation of cutaneous nerves showed two peaks in the case of wing nerve stimulation and one peak with leg nerve stimulation. Lesions of the DC or the ipsilateral dorsolateral funiculus (DLF) at a high cervical level (C4) indicate that a main input exists from the wing through the DC and from the leg through the DLF. With small injections of the fluorescent dye Fast blue into parts of the DCN it could be shown that aside from a primary afferent projection a well-developed postsynaptic dorsal column system exists only for the wing and that it takes its origin in the neurons of the lamina IV of the spinal dorsal horn.