not-yet-known not-yet-known not-yet-known unknown In vivo magnetothermal stimulation and fear behavior analysis The AMF exposure was set to 20 mT and 290 kHz for the magnetothermal genetic stimulation experiment. Cameras automatically recorded animal behaviors, and their movement trajectories were analyzed using Any-maze software. Total freezing time during each trial was used as an index of fear behaviors and converted to a percentage for analysis. The same contexts (odors, wall, color, flooring and sound-attenuating cabinet) were used to minimize contextual freezing. The percentage of freezing time spent during each FVIOs-treated trial was compared across groups (including SPIOs-treated, without AMF exposure).