Final answer:
All senses except olfaction (smell) are relayed through the thalamus before reaching the cerebral cortex for conscious perception. Olfactory signals directly project to the cerebral cortex without going through the thalamus.
Step-by-step explanation:
Sensory impulses from all of the senses except olfaction (sense of smell) converge on the thalamus and synapse in at least one of its nuclei. The thalamus is vital for relaying sensory information to the cerebral cortex, where we become aware of these sensations. However, the olfactory system is unique in that its sensory signals bypass the thalamus and directly project to the cerebral cortex, the limbic system, and the hypothalamus for processing.
The thalamus acts not only as a relay station but also processes information before it reaches the cortex. This processing can determine the significance or attention given to the incoming sensory stimuli, such as visual information. In all other sensory pathways aside from olfaction, the thalamus is a necessary synapse for signals to reach the cerebral cortex.