Behavioral changes in the mice in response to different doses of the nanomediator were investigated using magnetothermal activation of the CeA. As shown in Fig. 4c, 0.05 μg of anti-His-FVIOs induced freezing behavior in mice in response to AMF application. The percentage of freezing time was greater during the AMF application period than during the AMF OFF period (Figure 4c). However, none of the mice showed fear behaviors when injected with the same dose of SPIOs (Figure 4d). Further studies revealed that the SPIOs could magnetothermally evoke significant freezing responses only at doses greater than 0.80 μg, which was 16-fold greater than the dose of FVIOs needed to elicit a response. Moreover, no significant differences in freezing behaviors were noted in the control groups with or without FVIO injection, AMF application, and TRPV1 overexpression. The latency to fear response of the mice was also recorded to analyze the temporal resolution of magnetothermal neurostimulation. Notably, FVIO (0.05 μg)-treated mice exhibited a fear behavioral response with an average latency time of 2.51 s, which was 2.3-fold faster than that of the SPIO (0.80 μg)-treated group (Figure 4e). Compared with the previously reported latency time of tens of seconds in mouse experiments, FVIO-mediated stimulation has been demonstrated to be a superior technique for improving the temporal resolution of in vivo magnetothermal neuromodulation.