Temporal Interference and Depression

TI involves simultaneous delivery of independent currents to the brain at slightly different kHz frequencies, which are individually too high to recruit neural firing. However, the difference ('beat') frequency where the currents overlap (i.e., temporally interfered) is low enough to drive neural activity. The interferometrically derived low frequencies have been demonstrated to activate neurons at a selected focus without activation of surrounding regions in awake mice. The safety of the TI paradigm has been demonstrated in over 60 healthy human volunteers, and finite element modeling of simulations of TI fields in human anatomical models suggests that large subcortical structures such as the hippocampus or SCC could be selectively targeted. However, the precise TI parameters for selective engagement of SCC in healthy participants and in MDD is currently unknown.

Electrodes will be placed in the same location on the head as that for the TI intervention; 0 mA of electrical current will be delivered to the brain (compared to 2 mA in the active intervention arm), therefore it is expected to elicit no changes in neural activity.