The term olfactory bulb refers to a structure that mediates the second level of sensory information processing in the olfactory system ( Buck-2013 ). It has two variants, namely, the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), embedded in the same OLB structure.. The MOB is found in the human ( Buck-2013 ), macaque ( Price-1990 ), rat ( Swanson-2004 ) and and mouse ( AMBA-2024 ). A functionally significant AOB is found only in the rodent ( Ahang-2003 ).. Neurons in the OLB have receptors for testosterone, and destruction of the bulb greatly reduces male sexual behavior in the rat ( Cunningham-2012 ). They also have receptors for estrogen and progesterone ( Abaffy-2023 ).. So, the OLB presumably adds selinformation as to the sex and sexual receptivity of the perceiver to the sensory signal that it transmits to the third signal processing level of the olfactory system, For more on functions, see main olfactory bulb and accessory olfactory bulb. Updated 25 Jul 2024.