Human olfactory region. Computer artwork of a cutaway profile view of a section of a person's head showing the inside of the nose and nasal cavity. This is the region responsible for detecting odours. The olfactory bulb can be seen (upper right) in the forebrain (prosencephalon) with the many projections of its olfactory receptor cells ( branching filaments) reaching 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.