Supraspinal Circuit Mechanisms Underlying Itch Processing

Itch and pain are distinct somatosensory modalities that share overlapping anatomical pathways, particularly in the peripheral nervous system. However, compared with pain, the supraspinal mechanisms underlying itch perception and modulation remain poorly understood, limiting progress in central therapeutic strategies.

This narrative review synthesizes recent mechanistic studies-primarily from rodent models-to examine supraspinal circuits underlying itch. Relevant literature was identified through targeted database searches and reference tracking.

Accumulating evidence indicates that itch is encoded and modulated by distributed brain networks that contribute to both its sensory perception and emotional components. These networks partially overlap with, yet are distinct from, those mediating pain, revealing convergent and divergent mechanisms at the supraspinal level. Recent studies further demonstrate interactions among itch, pain, and other sensory modalities, highlighting the complexity of central sensory integration.

A clearer understanding of supraspinal itch circuits and their interaction with pain-related pathways provides important insights into central sensory processing and may facilitate the identification of novel therapeutic targets for chronic and refractory itch.