ABSTRACT
Cytoarchitecture of the ventrolateral superficial area of the medulla was studied on normal rabbit Nissl sections.There was a superficial area of small and medium sized cells,mostly fusiform,lateral to the pyramid.In middle and upper parts of the medulla superficial cells were also found in less amount in more lateral regions. At the middle medullary level there was a band of cells about 300 ?m from the surface with medium sized ones as its most prominent elements. HRP or WGA-HRP was injected in 10 rabbits into the cervical,thoracic or lumbar spinal cord unilaterally and its connection with the ventrolateral superficial area of the medulla was traced.Labeled cells were found in all cases along the pyramid.The lateral part of the superficial area was less labeled.The medium sized cell band at the middle medulla was markedly labeled,especially in thoracic injec- tion cases.More labeled cells were found in cervical injection cases in an area ventromedial to the facial nucleus. Anterogradely labeled terminal arborizations were in general small in amount, somewhat more prominent in cervical cases. The relation between the ventrolateral superficial area and the chemosensitive area is disscussed.