痒是一种能引起强烈搔抓欲望的不愉快感觉。痒觉信息从皮肤产生，由外周神经元传入脊髓，经处理后最终传输到大脑。与外周、脊髓水平相比，痒觉在大脑水平的研究还相对较少。得益于近几年在体研究技术的发展，解析痒觉信息传递的大脑中枢神经环路机制成为可能。随着神经科学研究技术的快速进步，一系列解析痒觉在脑内处理机制的重要成果被陆续报道。本综述主要总结了痒觉，尤其是化学痒，从外周到大脑的研究进展。

Itch is an unpleasant feeling that elicits a strong desire to scratch. After being initiated at the skin, the itch signal is subsequently transferred down the spinal cord to the brain, where the itch information is processed. Our understanding of the peripheral and spinal mechanisms of itch has advanced significantly in recent years, but our knowledge of how brain neural circuits modulate itch is still limited. Aided by in vivo imaging techniques, researchers can decipher the neural mechanisms of itch sensation at the brain level. With the rapid progress of modern neurotechnologies, a series of significant achievements in central neural mechanisms of itch have been reported. The authors reviewed the recent advances in itch sensation from periphery to the central nervous system (CNS), focusing on chemical itch.