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The main function here is the thalamus acting as the brain’s central relay station. Within the diencephalon, the thalamus receives almost all sensory information from the body and head and then projects that information to the appropriate areas of the cerebral cortex, where perception becomes conscious. It also channels motor information, carrying signals from the basal ganglia and cerebellum through specific thalamic nuclei to the motor cortex, helping to plan and execute movements. This relay system is what lets you perceive touch, temperature, vision, hearing, and body position, and then respond with coordinated movement.

A helpful detail is that some sensory pathways stop at the thalamus before reaching the cortex, while others pass through to cortical areas via dedicated thalamic nuclei (for example, the lateral geniculate nucleus for vision, the medial geniculate for hearing, and the ventral posterior nuclei for somatosensation). The olfactory system is a notable exception and largely bypasses the thalamus, going directly to olfactory cortex.

The other parts of the diencephalon serve different roles—autonomic and endocrine regulation (hypothalamus), circadian and mood-related functions (epithalamus), and components involved in movement circuitry (subthalamus). But when it comes to distributing sensory and motor information to the cortex, the thalamus is the key structure.