Which structure is primarily involved in transmitting olfactory signals to the brain?

The primary structure involved in transmitting olfactory signals to the brain is the olfactory bulb. The olfactory bulb processes sensory information from the olfactory receptors found in the nasal cavity. Once these receptors detect odors, they send signals to the olfactory bulb, where the initial processing of these signals occurs.

The olfactory bulb then sends the refined information via the olfactory tract to different brain regions, notably the olfactory cortex, which is responsible for the perception of smell. Therefore, while the olfactory tract is indeed involved in the transmission of olfactory signals, it works in conjunction with the olfactory bulb, which is the first major site of processing for olfactory information.

In this context, the optic nerve does not relate to the sense of smell, as it is responsible for transmitting visual information from the retina to the brain. The basilar artery is unrelated to olfactory processing; it supplies blood to structures in the brain but does not play a direct role in olfaction.