Why doesn’t olfaction pass through the thalamus when all the other senses do?

First I’ll explain why the olfactory sense is different from the others, then I will show how it works differently in the limbic system. Because all the sensory nerves besides olfactory ones traverse the thalamus, we often think of the thalamus as the first stop in sensory processing, but it is really the final stop, or culmination, of the downward pathways of the predictive brain. Historically, brain science has described the brain as something like a computer, suggesting it works with an input-process-output (IPO) model. In this model, it would make sense to gather all the senses in a place like the thalamus and forward them to the sensory cortex areas for processing into output/muscle commands. We know this is not how the brain works, though it may have been how the very first brains in the mud of ocean worked; we’ll never know because soft bits like brains don’t fossilize. <a href="https://l-teralthinker.medium.com/why-doesnt-olfaction-pass-through-the-thalamus-when-all-the-other-senses-do-c0079484ee5b">Learn More</a>