Decreasing ventromedial prefrontal cortex deactivation in risky decision making after simulated microgravity: Effects of -6 degree head-down tilt bed rest oleh Li-Lin eRao, Yuan eZhou, Zhu-Yuan eLiang, Hengyi eRao, Rui eZheng, Yan eSun, Cheng eTan, Zhi-Qiang eTian, Xiao-Ping eChen, Chun-Hui eWang, Yan-Qiang eBai, Shan-Guang eChen, Shu eLi