Green light induces antinociception via visual-somatosensory circuits
Peng Cao, Mingjun Zhang, Ziyun Ni, Xiang-Jie Song, Chen-Ling Yang, Yu Mao, Wenjie Zhou, Wanying Dong, Xiaoqi Peng, Changjian Zheng, Zhi Zhang, Yan Jin, Wenjuan Tao
Abstract
Light has been shown to relieve pain, but the underlying neural mechanisms remain unknown. Here, we show that low-intensity (200 lux) green light treatment exerts antinociceptive effects through a neural circuit from the visual cortex projecting to the anterior cingulate cortex (ACC) in mice. Specifically, viral tracing, in vivo two-photon calcium imaging, and fiber photometry recordings show that green light activated glutamatergic projections from the medial part of the secondary visual cortex (V2M Glu ) to GABAergic neurons in the ACC, which drives inhibition of local glutamatergic neurons (V2M Glu →ACC GABA→Glu ). Optogenetic or chemogenetic activation of the V2M Glu →ACC GABA→Glu circuit mimics green-light-induced antinociception in both neuropathic and inflammatory pain model mice. Artificial inhibition of ACC-projecting V2M Glu neurons abolishes the antinociception induced by green light. Taken together, our study shows the V2M-ACC circuit as a potential candidate mediating green-light-induced antinociceptive effects.