Modulation of Repetitive Transcranial Magnetic Stimulation on Mood and Cognitive Function in Simulated Weightlessness Rats

During spaceflight, microgravity can cause negative impact on emotion and cognitive function. However, few effectively preventive methods have been developed yet. Previous studies showed that repetitive transcranial magnetic stimulation (rTMS), as a novel non-invasive technique, alleviated depression and cognitive dysfunctions. In the present study, the hindlimb unloading (HU) rat model was used to simulate microgravity. And then, in experiment 1 we investigated whether 3-week HU induced anxiety and memory impairment. Behavioral tests including open field test, elevated plus maze test, Y maze test, and Morris water maze were performed. In experiment 2, during the simulated microgravity, HU rats were exposed to a 2-week rTMS (10Hz). After that, the same behavioral experiments were carried out. The results showed that spontaneous activity of HU rats decreased, reflected in the fewer entries to the central area in open field test, while rTMS protected against the harmful effect. No difference was observed in the behavioral performance of spatial cognition between control and HU rats. Our data suggests that rTMS-treatment during simulated microgravity plays a role in protecting against anxious emotion induced by microgravity simulation.