Network Action Of Subcallosal Cingulate White Matter Deep Brain Stimulation

AO_SCPLOWBSTRACTC_SCPLOWDeep brain stimulation (DBS) within the subcallosal cingulate cortex (SCC) alleviates symptoms of depression through an unclear therapeutic mechanism. Precise stimulation of SCC white matter (SCCwm) is thought to be necessary to achieve therapeutic response, and clinical recordings can now be used to test this hypothesis. In this paper we characterized the where, what, and how of SCCwm-DBS immediate effects, its network action, at therapeutic stimulation frequencies. First, using simultaneous LFP and EEG, we determined whether the effects of SCCwm-DBS are local at the SCC and/or remote at downstream cortical regions. We then charactized the spatial pattern effected by DBS across high-density EEG, finding multi-oscillatory response modes. Finally, we demonstrated that these modes are spatially consistent with white matter tracts targeted during surgical implantation. These results clarify the immediate actions of SCCwm-DBS as broad low-frequency power increases in brain regions downstream to stimulated white matter. This quantitative characterization of SCCwm-DBS network action has implications for future clinical trials, and may accelerate adaptive therapy optimization.