Olfactory bulb

The olfactory bulb (Latin: bulbus olfactorius) is a neural structure in the forebrain of vertebrates that is involved in olfaction, or the sense of smell. It transmits olfactory information to the other brain regions including the amygdala, orbitofrontal cortex (OFC) and hippocampus where it contributes to emotion, memory and learning.

The bulb is divided into two distinct structures: the main olfactory bulb and the accessory olfactory bulb. The main olfactory bulb connects to the amygdala via the piriform cortex of the primary olfactory cortex and directly projects from the main olfactory bulb to specific amygdala areas. The accessory olfactory bulb resides on the dorsal-posterior region of the main olfactory bulb and forms a parallel pathway.

Destruction of the olfactory bulb results in ipsilateral anosmia, while irritative lesions of the uncus can result in olfactory and gustatory hallucinations.