Kipuaisti

Kipuaisti is the Finnish term for the sensory and perceptual system that detects, transmits, and interprets pain signals. It encompasses nociception—the neural processes by which noxious stimuli are encoded—and the subjective experience of pain that results in emotional and cognitive responses. Although related, nociception is not synonymous with pain; pain includes perceptual and affective dimensions shaped by context, mood, and expectations.

Peripheral detection and transmission occur when specialized nociceptors respond to mechanical, thermal, and chemical stimuli. Signals travel via A-delta fibers (fast, sharp pain) and C fibers (slow, dull pain) to the dorsal horn of the spinal cord, cross to the contralateral spinothalamic tract, and ascend to the thalamus. From there, information reaches the primary and secondary somatosensory cortices (localization and intensity) as well as the insula and anterior cingulate cortex (affective and evaluative aspects of pain).

Pain perception is modulated by descending pathways originating in brainstem structures such as the periaqueductal gray and rostral ventromedial medulla. Endogenous systems, including opioidergic and other neurotransmitter networks, can dampen or amplify signaling. Chronic pain can involve sensitization—peripheral and central—that makes responses to stimuli more pronounced or persistent.

Clinical relevance and assessment rely on a biopsychosocial approach. Kipuaisti is evaluated with patient-reported measures (for example, numerical rating scales or visual analogue scales) and integrated with psychological and social factors. Distinctions between nociceptive, neuropathic, and inflammatory pain guide diagnosis and treatment.