Inhibition of midfrontal theta with transcranial ultrasound explains greater approach versus withdrawal behavior in humans

Mechanobiological insight into brain diseases based on mechanosensitive channels: Common mechanisms and clinical potential

“… 188 The transcranial ultrasound stimulation targeting unilateral prefrontal cortex promotes an approach‐like risky behavior. 189 The potential mechanism in mesoscopic level might lie on the downregulation of the resting‐state network connectivity associated with emotion, 188 and the decrease of midfrontal theta activity that is associated with several psychiatric diseases. 189 , 190 When using a daily repeated ultrasound with the same frequency and duration but a lower ultrasound power on depressed participants, trait worry level, the chronic feeling of nervousness, is decreased, while the other quantitative indexes for evaluating depression are not changed.…”

“…In healthy people, utilizing 500 kHz transcranial focused ultrasound to stimulate the unilateral inferior frontal gyrus for 30 s or 2 min increase self‐reported emotional states 188 . The transcranial ultrasound stimulation targeting unilateral prefrontal cortex promotes an approach‐like risky behavior 189 . The potential mechanism in mesoscopic level might lie on the downregulation of the resting‐state network connectivity associated with emotion, 188 and the decrease of midfrontal theta activity that is associated with several psychiatric diseases 189,190 .…”

A review of functional neuromodulation in humans using low-intensity transcranial focused ultrasound

“…In psychological investigations by Forster and colleagues (2023a,b) [47,48], tFUS administration to the right IFG modulated the emergence of 'learned helplessness' and midline theta EEG activities [48], and altered the processing of 'stimulus probability' and midfrontal theta EEG, without affecting 'control perception' [47]. Another study by the same group, conducted by Ziebell et al (2023) [49], demonstrated that tFUS to the right prefrontal cortex (PFC) decreased midfrontal theta EEG activity, accompanied by increased 'approach behavior' while 'withdrawal behavior' decreased, during a virtual T-maze task. Fine et al (2023) [50] reported that when tFUS was applied to the right IFG during a 'stop' signal in a stop-signal task, behavioral inhibition was improved, accompanied by shorter P300 onset latencies.…”

“…Single-element, focused (Neurotrek U+) 500 kHz Sanguinetti JL et al 2020 [46] EEG site F8 Reznik SJ et al 2020 [73] EEG site F8 Forster A et al 2023a [48] EEG site F8 Forster A et al 2023b [47] EEG site F8 Ziebell P et al 2023 [49] EEG site F8 4 List of tFUS/TUS transducers grouped by manufacturer, transducer type, and fundamental frequency (FF) used in the reviewed human studies, along with the targeting methods utilized reflections. Recent technological advances even allow for semi-real/real-time acoustic simulation, previously challenging due to high computational load.…”

Dynamic Changes in Human Brain Connectivity Following Ultrasound Neuromodulation

“…Therefore, the number of human-based studies is rapidly growing. While many of them enlighten the processes which underpin FUS (increased cortical excitability [11][12][13][14][15] through GABA inhibition [16]; brain activity in the target region could be either increased [12,[17][18][19][20][21] or decreased [22]; altered functional connectivity [13,16,17,23,24]; increased NMDA-dependent synaptic plasticity [25]), others already moved into more complex research on behavioural changes (sensory discrimination [18,[26][27][28]; motor inhibition [11,[29][30][31]; reaction time [32]; approach and withdrawal behaviours [33]; mood [24]; pain [34]; fear [35]), and the more audacious focused on pathological conditions (epilepsy[36-38]; Alzheimer's disease [39] and other dementia [40]; consciousness disorders [41]; tremor [42]; Parkinson's disease [43]; depression [44]; chronic pain [45]). However, FUS outcomes remain complex to interpret due to an incomplete understanding of the mechanisms involved.…”