a small, oval area at the base of the cerebral hemisphere, between the diverging medial and lateral olfactory striae, in the anteromedial part of the anterior perforated substance; it is formed by a small area of allocortex characterized by the presence of the islands of Calleja. Corresponding to a much more prominent structure in nonprimate mammals (especially rodents and insectivores), the olfactory tubercle receives fibers from the olfactory bulb by way of the intermediate olfactory stria; it has efferent connections with the hypothalamus and the mediodorsal nucleus of the thalamus. SYN: tuberculum olfactorium [TA].