Neurones with axons ascending the dorsal columns

Abstract

The dorsal columns (posterior columns, posterior funiculi, fasciculus gracilis and fasciculus cuneaatus) are commonly considered simply from the point of view that they contain ascending axons of primary afferent fibres whose cell bodies are located in the dorsal root ganglia. This view is manifestly incorrect. Indeed it has been known since the last century (Edinger 1889) that some dorsal column fibres arise from neurones in the grey matter of the spinal cord. Although some of the non-primary axons in the dorsal columns have short axons, ascending and descending for only a segment or two, some have been recognized for many years as ascending as far as the dorsal column nuclei (Rothmann 1899; Münzer and Wiener 1910). Other long axons connect the spinal enlargements with each other (Barilari and Kuypers 1969) and in rodents a part of the corticospinal tract descends through the dorsal columns (King 1910; Ranson 1913b, 1914b; Simpson 1914, 1915a, b; Reveley 1915; Douglas and Baar 1950).