Transcranial Focused Ultrasound Alters Conflict and Emotional Processing, Physiology, and Performance II: Right Anterior Insula/Frontal Operculum Targeting

The dorsal anterior cingulate cortex (dACC) operates as an integrator of bottom-up and top-down signals and is implicated in both cognitive control and emotional processing. The dACC is believed to be causally involved in switching between attention networks, and previous work has linked it to cognitive performance, concentration, relaxation, and emotional distraction. The present study was designed to evaluate the feasibility of influencing default mode network (DMN) activity and emotional attention by targeting and modulating the dACC with transcranial focused ultrasound (tFUS). Subjects were divided into two groups, one receiving MR-neuronavigated tFUS to the dACC and the other an identical, but inactive tFUS sham. Subjects performed a modified version of the Erikson flanker paradigm using fear and neutral faces as emotional background distractors. Our observations demonstrate that tFUS can be targeted to the human dACC to produce effects consistent with those expected from relaxed contention, including significantly reduced reaction time slowing due to emotional distractors, and an increase in parasympathetic markers of the HRV. These results suggest that tFUS altered emotional processing and enhanced sustained attention, perhaps by facilitating reduced attentional engagement with emotional distractors and reduced need for attention switching evidenced by significant effects on event related potentials (ERPs), reduced alpha suppression, and modulation of delta and theta EEG activity. We conclude that the dACC represents a viable neuroanatomical target for tFUS in order to modulate DMN activity, including emotional attention, conflict resolution, and cognitive control. These effects of dACC-targeted tFUS may prove useful for treating certain mental health disorders known to involve perturbed DMN activity, such as depression and anxiety.