somatosensoriset

Somatosensoriset is the somatosensory system, the part of the nervous system that conveys information about touch, temperature, pain, and body position from the periphery to the central nervous system. It includes receptors in the skin, muscles, joints, and viscera, which transduce mechanical, thermal, and chemical stimuli into neural signals. Major modalities include exteroception (surface touch, pressure, vibration, temperature) and proprioception (joint and muscle sense).

Receptors such as mechanoreceptors, thermoreceptors, nociceptors, and proprioceptors initiate signals that travel through peripheral nerves to the spinal cord and brainstem. Within the spinal cord, distinct pathways carry different modalities: the dorsal columns (gracile and cuneate fasciculi) convey fine touch and proprioception; the spinothalamic tract conveys pain and temperature; the trigeminal pathway handles facial somatosensation.

In the thalamus, most somatosensory information reaches the ventral posterior nucleus before projecting to the primary somatosensory cortex (S1) in the postcentral gyrus. There, a somatotopic map, commonly referred to as the sensory homunculus, represents the body and integrates information about location, intensity, and texture. Secondary sensory areas and associative cortices contribute to object recognition, texture discrimination, and the coordination of movement.

Clinical relevance includes sensory loss or distortion from peripheral nerve injury, spinal cord damage, thalamic lesions, or cortical dysfunction. Conditions such as numbness, allodynia, neuropathic pain, and impaired proprioception illustrate the practical importance of the somatosensoriset system in everyday function and motor control.