Intermittent Theta Burst Stimulation (iTBS) for Emotion Regulation in Bipolar Disorder

Transcranial magnetic stimulation (TMS) is a non-invasive tool for modulating patterns of brain activation and circuit connectivity. It uses electromagnetic pulses to induce electric currents over the cortex that serve to depolarize or hyperpolarize neurons, thereby changing patterns of synaptic activity. This study uses intermittent theta burst stimulation (iTBS), an efficient TMS protocol that uses high frequency (50Hz) triplets of TMS given every 200 milliseconds (i.e. at 5 Hz).

Sham stimulation works by blocking the magnetic field with an internal spacer on the sham side of the TMS coil, allowing the operator to place the coil surface against the scalp. A brief electric pulse calibrated to the stimulator output is delivered to the scalp simultaneous to the TMS pulse to mimic the scalp sensation during the sham condition. 75 Importantly, the electric pulse is calibrated to the stimulator output to ensure a realistic sham condition.