Somatosensorisella

Somatosensorisella is a Finnish term used in neuroscience and medicine to describe phenomena, structures, or processes related to the somatosensory system. This system conveys information about the body's surface, position, and internal state, including touch, proprioception, temperature, and nociception (pain).

The somatosensory modalities include mechanoreception (touch, pressure, vibration), proprioception (sense of body position and movement), thermoreception (temperature), and nociception (pain). Receptors responsible for these modalities are diverse: cutaneous mechanoreceptors in the skin (such as Merkel cells, Meissner corpuscles, Pacinian corpuscles, and Ruffini endings), proprioceptors in muscles and joints (muscle spindles, Golgi tendon organs, joint receptors), thermoreceptors, and nociceptors.

Ascending pathways relay somatosensory information to the brain. Signals from the body travel via peripheral nerves to the spinal cord, where many modalities split into distinct tracts. Fine touch and proprioception largely ascend through the dorsal columns (dorsal column–medial lemniscus pathway), while pain and temperature primarily travel through the spinothalamic tract. Most pathways cross to the opposite side at some level in the CNS and project to the thalamus, particularly the ventral posterolateral nucleus, before reaching the primary somatosensory cortex in the postcentral gyrus. There, sensory information is mapped somatotopically, forming a cortical representation often described by a sensory homunculus; further processing occurs in association areas to integrate touch with context and memory.

Clinical relevance includes sensory deficits from nerve or CNS lesions, neuropathies, and reconstruction or rehabilitation after injury. Assessment typically involves tests of touch, pain, temperature, vibration, and proprioception, and the study of somatosensory processing informs both diagnosis and therapy.