[Phylo- and ontogenetic development of the nucleus of the brachium of the inferior colliculus]

In recent neuromorphological investigations and in studying the passage, as an addition to nuclei of the auditory system so called "parabrachial area" was subjected to a special comparative cytoarchitectonic investigation and terminological definition, since the term "parabrachial nucleus" has already been reserved in neuromorphology to designate other brain formations. The investigation has demonstrated that the term "nucleus of the inferior quadrigemina brachium" is more suitable to the form studied. This nucleus has been stated to penetrate deeply into the inferior tuberculum corpori quadrigemina, unlike the previous notion according to which it was believed to be situated between the internal geniculate body and the inferior tuberculum corpori quadrigemina. Therefore, two parts have been distinguished in the formation in question, inherent to all the mammalia studied, including the man. One of them—extracollicular portion, though it has not been previously studied from the view of comparative architectonics, nevertheless, it has been described in literature. The other—intracollicular portion is described for the first time in the work. In spite of a close topographic-anatomical proximity with the inferior corpora quadrigemina, the intracollicular portion of the nucleus cannot be a derivative from the latter.