why thalamus not act as relay station for olfactory sensation

Answer 1

The thalamus is indeed responsible for relaying most sensory information from the peripheral nervous system to the cerebral cortex, but it does not play a significant role in olfactory sensation.

Olfactory sensation, or the sense of smell, is unique among the senses because it bypasses the thalamus and directly connects to higher brain regions. When we inhale odorants, they bind to olfactory receptors in the nasal cavity. These receptors send signals directly to the olfactory bulb, which is located at the front of the brain and is dedicated to processing smell.

From the olfactory bulb, the information is relayed to the olfactory cortex, which is located in the frontal and temporal lobes of the brain. This direct connection allows for quick and efficient processing of smell without the need for the thalamus as an intermediary.

Overall, the exclusion of the thalamus in olfactory processing is thought to be related to the unique evolutionary origins and functional requirements of the sense of smell.