THE AVIAN SOMATOSENSORY SYSTEM - THE PATHWAY FROM WING TO WULST IN A PASSERINE (CHLORIS-CHLORIS)

The organization of the wing component of the dorsal column-medial lem niscal pathway, and somatosensory projections from the thalamus to the Wulst, are described for an oscine member of the major group of birds , the Passeriformes. Wing primary afferents terminate throughout the c ervical spinal cord, but between the brachial enlargement and the spin o-medullary junction, they are confined to medial lamina V. Within the medulla, terminations extend rostrally and laterally to occupy the cu neate (Cu) and external cuneate nuclei (CuE). Ascending projections fr om Cu and CuE form the contralateral medial lemniscus, which has exten sive projections to the midbrain and to the thalamus. In the midbrain the projections surround the central auditory nucleus densely and term inate more sparsely within it. In the thalamus, specific terminations were observed in nucleus uvaeformis and in the nucleus dorsalis interm edius ventralis anterior (DIVA). DIVA projects to the ipsilateral rost ral Wulst where it terminates in the intercalated hyperstriatum access orium, in a distinct, regular patchy fashion. The somatosensory projec tions to the telencephalon in green finch are similar to those in pige on, but dissimilar to those in budgerigar.