EEG Synchronized TMS Trial for Depression

Daily prefrontal TMS for depression, as developed by the PI, involves delivering TMS pulses to the prefrontal cortex and not assessing what the actual EEG phase is of the person's brain. In cardiology, in order to stimulate the heart effectively, one has to know the rhythm and phase of the heartbeat in order to perform cardioversion. The investigators wonder if it is important to time the brain stimulation with the phase of the person's brain. The brain has definite rhythms, and cycles through being excited or resting. A common EEG rhythm is alpha frequency. Theoretically, the effect of the TMS pulse might be diminished if it was delivered when the brain was temporarily cycling into an off state. In the r21 part of this grant, the investigators designed and constructed a combined TMS/EEG/fMRI system. With that equipment the investigators found that TMS pulses have different effects deeper in the brain as a function of the EEG alpha phase. Pulses delivered during a rising phase produce larger blood flow changes deeper in the brain than do pulses delivered during a falling phase. In the R33 phase of the grant the investigators now take that idea into a small clinical trial in depression to test if synchronized pulses have a larger clinical effect than do non-synchronized pulses.