{Reference Type}: Journal Article
{Title}: Transcranial focused ultrasound of the amygdala modulates fear network activation and connectivity.
{Author}: Chou T;Deckersbach T;Guerin B;Sretavan Wong K;Borron BM;Kanabar A;Hayden AN;Long MP;Daneshzand M;Pace-Schott EF;Dougherty DD;
{Journal}: Brain Stimul
{Volume}: 17
{Issue}: 2
{Year}: 2024 Mar-Apr 4
{Factor}: 9.184
{DOI}: 10.1016/j.brs.2024.03.004
{Abstract}: <B>BACKGROUND: </B>Current noninvasive brain stimulation methods are incapable of directly modulating subcortical brain regions critically involved in psychiatric disorders. Transcranial Focused Ultrasound (tFUS) is a newer form of noninvasive stimulation that could modulate the amygdala, a subcortical region implicated in fear.<BR><B>OBJECTIVE: </B>We investigated the effects of active and sham tFUS of the amygdala on fear circuit activation, skin conductance responses (SCR), and self-reported anxiety during a fear-inducing task. We also investigated amygdala tFUS' effects on amygdala-fear circuit resting-state functional connectivity.<BR><B>METHODS: </B>Thirty healthy individuals were randomized in this double-blinded study to active or sham tFUS of the left amygdala. We collected fMRI scans, SCR, and self-reported anxiety during a fear-inducing task (participants viewed red or green circles which indicated the risk of receiving an aversive stimulus), as well as resting-state scans, before and after tFUS.<BR><B>RESULTS: </B>Compared to sham tFUS, active tFUS was associated with decreased (pre to post tFUS) blood-oxygen-level-dependent fMRI activation in the amygdala (F(1,25) = 4.86, p = 0.04, η2 = 0.16) during the fear task, and lower hippocampal (F(1,27) = 4.41, p = 0.05, η2 = 0.14), and dorsal anterior cingulate cortex (F(1,27) = 6.26, p = 0.02; η2 = 0.19) activation during the post tFUS fear task. The decrease in amygdala activation was correlated with decreased subjective anxiety (r = 0.62, p = 0.03). There was no group effect in SCR changes from pre to post tFUS (F(1,23) = 0.85, p = 0.37). The active tFUS group also showed decreased amygdala-insula (F(1,28) = 4.98, p = 0.03) and amygdala-hippocampal (F(1,28) = 7.14, p = 0.01) rsFC, and increased amygdala-ventromedial prefrontal cortex (F(1,28) = 3.52, p = 0.05) resting-state functional connectivity.<BR><B>CONCLUSIONS: </B>tFUS can change functional connectivity and brain region activation associated with decreased anxiety. Future studies should investigate tFUS' therapeutic potential for individuals with clinical levels of anxiety.