痒感多由蚊虫叮咬、过敏等引发的局部炎症产生，通过细直径慢神经元经脊髓丘脑束传导至大脑。而皮肤中的机械感受器能感知触摸和震动，其信号通过粗直径快神经元经背柱传导。脊髓内两类神经元通过中间神经元交联，触摸信号会激活抑制痒感传导的神经元，这就是 “闸门理论”—— 触摸能 “关闭” 痒感通道。此外，触摸刺激大脑深层结构会反向抑制痒感传递，功能性磁共振成像研究还显示，挠痒能激活大脑奖励中枢，带来愉悦感。

Mosquito bites are itchy and we tend to scratch itchy things. The scratching feels good in the short term but tends to hasten and exacerbate swelling and inflammation. This leads to more scratching ...

Scratch-off tickets are big money for state-run lotteries. Is it the promise of winning big that keeps players in the game? Or is there something else happening in the brain? NOVA is available to ...

I remember it well: our dark winter of itch when the kids were small. It started with a note sent home—years before the pandemic—that my child had been exposed, not to a deadly virus but to lice.