thermoreception

Thermoreception is the sensory process by which organisms detect temperature changes on the skin and mucous membranes, enabling perception of warmth and coolness and contributing to thermal comfort and avoidance of harmful conditions. In humans and many vertebrates, thermoreception begins with specialized peripheral sensory neurons called thermoreceptors that respond to temperature shifts. These receptors are broadly categorized as cold receptors and warm receptors; some neurons respond across a range or to noxious temperatures, contributing to thermal pain.

Molecularly, thermoreception is largely mediated by temperature-sensitive ion channels, especially the transient receptor potential (TRP) family. TRPM8 is activated by cool temperatures and menthol, while TRPV1 is activated by heat and capsaicin. Other warm-sensitive channels include TRPV3 and TRPV4, and TRPA1 has a more variable role in cold and irritant detection in different species. Activation of these receptors generates action potentials that travel through peripheral nerves to the spinal cord.

Neural pathways for thermoreception project to the brain via the spinal cord, where signals ascend to the thalamus and then to the somatosensory cortex for conscious perception. Some thermoreceptive inputs also influence autonomic and affective responses through limbic circuits and brainstem centers. Thermoreception is distinct from thermoregulation—the latter being the body's automatic maintenance of internal temperature, though the two systems interact.

Clinical and research notes: alterations in thermoreception can result from nerve injury, diabetes, aging, or neuropathies. Understanding thermoreceptor function and TRP channels has implications for pain management, sensation disorders, and the treatment of thermal hyporesponsiveness or hypersensitivity.