Olfactory Tubercle

The olfactory tubercle (OT, tuberculum olfactorium) is a multi-sensory processing center in the olfactory cortex that plays a role in reward behaviors. The OT is a composite structure that receives direct input from the olfactory bulb and contains the morphological and histochemical characteristics of the ventral pallidum and the striatum of the forebrain (Heimer & Wilson 1975). In addition, the OT contains tightly packed cell clusters known as the Islands of Calleja, which consist of small granule cells. Even though it’s part of the olfactory cortex and receives direct input from the olfactory bulb, it has not been shown to play a role in processing of odors.

The OT is interconnected with numerous brain regions especially the sensory and arousal/reward centers, thus making it a potentially critical interface between processing of sensory information and the subsequent behavioral responses (Wesson & Wilson 2011). OT has also been shown to play a role in locomotor and attentional behaviors specifically in social and sensory responsiveness (Hitt, Bryon & Modianos 1973) and it may be necessary for behavioral flexibility (Koob et al. 1978).