The thalamus is a large mass of gray matter on the lateral walls of the third ventricle forming the dorsal part of the diencephalon. Nerve fibers project out of the thalamus to the cerebral cortex in all directions, known as the thalamocortical radiations, allowing hub-like exchanges of information. It has several functions, such as the relaying of sensory and motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness.

चेतक या थैलेमस मस्तिष्क का एक भाग है जो प्रमस्तिष्क प्रांतस्था और मध्यमस्तिष्क के बीच स्थित है।