Final answer:
The thalamus is a collection of nuclei that receives and processes sensory information before it is sent to the cortex, except for smell. It influences what stimuli are important and receives attention.
Step-by-step explanation:
The thalamus is a collection of nuclei that relay information between the cerebral cortex and the periphery, spinal cord, or brain stem. All sensory information, except for the sense of smell, passes through the thalamus before processing by the cortex. The thalamus does not just pass the information on, it also processes that information by influencing what stimuli are important and what receives attention.
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