Projections from the cochlear nuclear complex to the inferior colliculus
The substantial projections from the cochlear nuclei to the inferior colliculus (IC) do not seem to have been generally recognized as a common mammalian characteristic until about the late 1960s. Although they were described in some of the earliest experimental studies of the auditory pathways (Woollard and Harpman 1940, q.v., for a discussion of the earlier literature on the subject; Barnes et al. 1943), the prevailing view appeared to be that most of the axons leaving the cochlear nucleus terminated in the superior olivary complex or nuclei of the lateral lemniscus and that the projections to the IC were sparse. Certainly, the matter appeared to be unresolved in 1953, as Stotler stated flatly in his influential article on brain stem auditory pathways in the cat that "all neurons reaching the level of the inferior colliculus are of the third order." It was not until the late 1960s and early 1970s that studies with sensitive degeneration techniques (cf. Nauta 1993) demonstrated conclusively that both the dorsal and ventral cochlear nuclei project directly to the contralateral inferior colliculus (cat: Warr 1966, 1969, 1972; Fernandez and Karapas 1967; van Noort 1969; Osen 1972; Rhesus monkey: Strominger and Strominger 1971; Strominger 1973; chimpanzee: Strominger et al. 1977; kangaroo rat: Browner and Webster 1975). In some cases, sparse ipsilateral projections were also reported.
