Modulation of bilateral motor cortex excitability using intermittent theta burst transcranial magnetic stimulation / 中华物理医学与康复杂志

ABSTRACT

Objective:To explore the effect of intermittent theta-burst stimulation (iTBS) of the cerebellum on the excitability of the M1 zone in the bilateral motor cortex and the duration of any effect.Methods:Twenty healthy youths were randomly assigned to a left or a right cerebellum iTBS group, each of 10. The resting motor threshold and motor evoked potential (MEP) of the motor cortex were determined before giving 600 pulses of iTBS. Then MEP was measured at the 5th, 10th, 15th, 20th, 25th, 30th, 35th and 40th minute after the intervention ended. Any changes in MEP amplitude were also analyzed.Results:①The average MEP amplitude in the right motor cortex had increased significantly in the left cerebellum iTBS group from the 5th to the 15th minute. The increase lasted at least 10 minutes. Then it had returned to the baseline value at the 35th minute. ②The MEP amplitude in the left motor cortex decreased slightly after iTBS of the left cerebellum began, but there were no significant changes. ③The MEP amplitude in the left motor cortex had a tendency to decrease after iTBS was administered to the right cerebellum, but that change too was not significant. ④The MEP amplitude of the right motor cortex decreased significantly only for the first 30 minutes.Conclusions:iTBS of the cerebellum can increase the excitability of the contralateral motor cortex. The effect can last 25 minutes. It can also decrease the excitability of the ipsilateral motor cortex for 30 minutes.