The central mesencephalic grey in birds: nucleus intercollicularis and substantia grisea centralis.

The question discussed in this paper is, whether the dorsomedial part of the intercollicular nucleus and central mesencephalic grey of birds are comparable to (parts of) the periaqueductal grey in mammals. The mammalian periaqueductal grey, and the avian dorsomedial part of the intercollicular nucleus + central mesencephalic grey are each part of pathways in control of functions such as vocalization and sexual behavior. The connectivity and histochemical features of the dorsomedial intercollicular nucleus and central mesencephalic grey are partly different and also differ partly from those of the mammalian periaqueductal grey. It is suggested that these areas in mammals and birds form comparable links in the emotional motor pathway that has been defined before in mammals.