Low-intensity Transcranial Ultrasound Stimulation (TUS) is a promising non-invasive technique for deep-brain stimulation and focal neuromodulation. Research with animal models and computational modelling has raised the possibility that TUS can be biased towards enhancing or suppressing neural function. Here, we first conduct a systematic review of human TUS studies for perturbing neural function and alleviating brain disorders. We then collate a set of hypotheses on the directionality of TUS effects and conduct an initial meta-analysis on the human TUS study reported outcomes to date (n = 32 studies, 37 experiments). We find that parameters such as the duty cycle show some predictability regarding whether the targeted area's function is likely to be enhanced or suppressed. Given that human TUS sample sizes are exponentially increasing, we recognize that results can stabilize or change as further studies are reported. Therefore, we conclude by establishing an Iowa-Newcastle (inTUS) resource for the systematic reporting of TUS parameters and outcomes to support further hypothesis testing for greater precision in brain stimulation and neuromodulation with TUS.

The authors have declared no competing interest.

Supported by National Institutes of Health USA (R01 DC04290), National Science Foundation (2342847) and Medical Research Council (UK). Ben Slater is supported by a BBSRC UK PhD studentship. M.K. was supported by the Engineering and Physical Sciences Research Council (EP/W004488/1 and EP/X01925X/1) and the Guangci Professorship Program of Rui Jin Hospital (Shanghai Jiao Tong University)

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