Human olfactory region. Computer artwork of a cutaway profile view of a section of a person's head showing the brain and the inside of the nose and nasal cavity. This is the region responsible for detecting odours. The olfactory bulb (centre, sausage-shaped) is situated in the forebrain (prosencephalon) and has many olfactory receptor cells (not shown) that project into the epithelial lining of the nasal cavity. The receptor cells pick up smell information and the olfactory bulb is responsible for transmitting these signals to the brain.