Light is recently recognized as a modulator able to activate the hippocampus and modulate memory processing, but little is known about the molecular mechanisms. Here, we report that in mice, a short pulse of white light before learning dramatically improves consolidation of contextual fear memory during the night. The light exposure increases hippocampal active p21-activated kinase 1 (PAK1) and CA1 long-term potentiation (LTP). These light effects are abolished in PAK1 knockout and dominant-negative transgenic mice, but preserved by expression of constitutively active PAK1 in the hippocampus. Our results indicate that light can act as a switch of PAK1 activity that modulate CA1 LTP and thereby memory consolidation without affecting learning and short-term memory.
Bibliographical noteFunding Information:
This work was supported by 973 Program of the Ministry of Science and Technology of China (2013CB835100 and 2015CB553502 to L.X.), Strategic Priority Research Program of the Chinese Academy of Sciences (XD2020002 to L.X.), National Science Foundation of China (31100775 and 31371141to Q-X.Z.) and Science and Technology Program of Yunnan Province (2013GA003 to L.X.). We thank Wei Xie and Zikai Zhou for providing PAK1 KO mice. We thank Yonggang Yao for some unincluded in vitro studies.
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