Development and application of rTMS device to murine model

Repetitive transcranial magnetic stimulation (rTMS) is attracting attention as a new treatment technique for brain lesions, and many animal studies showing its effects have been reported. However, the findings of animal application researches cannot directly represent the effects of rTMS in human, mainly due to size difference and mechanistic characteristics of rTMS. Therefore, the authors purposed to develop a mouse rTMS to simulate clinical application and to confirm. Firstly, a virtual head model was created according to magnetic resonance images of murine head. Then, simulations of rTMS stimulation with different coils were performed on the murine head phantom, and an rTMS device for mice was fabricated based on the optimal voltage conditions. Lastly, strengths of magnetic fields generated by the two rTMS devices, for human (conventional clinical use) and mouse (newly fabricated), were measured in air and on mouse head and compared. Resultantly, the magnetic field intensity generated by coil of mouse was lower than human's (p < 0.01), and no differences were found between the predicted simulation values and the measured intensity in vivo (p > 0.05). Further in vivo researches using miniaturized rTMS devices for murine head should be followed to be more meaningful for human.

Automated summary

Repetitive transcranial magnetic stimulation (rTMS) is being explored as a new treatment technique for brain lesions, but the effects in animals cannot directly represent the effects in humans due to differences in size and mechanistic characteristics. This study aimed to develop a mouse rTMS device to simulate clinical application. The magnetic field intensity generated by the mouse coil was lower than that by the human coil, and the predicted simulation values matched the measured intensity in vivo. Further research using miniaturized rTMS devices for mice should be conducted to make the findings more relevant to humans.