Neuromodulation techniques aim to modulate brain processes and treat neurological disorders non-pharmacologically by stimulating neural circuits. Low-intensity transcranial focused ultrasound (tFUS) is a noninvasive neuromodulation technology that uses focused ultrasound pressure waves, offering high spatial precision and the ability to target deep brain structures. I will present our work on the development and investigation of tFUS neuromodulation technology for noninvasive precision stimulation of brain circuits in animal models and human subjects. Our findings demonstrate the cell-type selectivity of tFUS neuromodulation and its ability to induce long-term depression using an in vivo rodent model. Using a 128-element transducer array with sub-millimeter lateral resolution, we demonstrate that tFUS can significantly suppress pain hypersensitivity by targeting the primary somatosensory cortex and insula in a humanized mouse model of sickle cell disease. In human studies, our work demonstrates the neuromodulatory effects of low-intensity tFUS in enhancing voluntary movement-related cortical activities, as evidenced by EEG source imaging. Additionally, our recent findings show that V5-targeted tFUS enhances alpha and theta oscillations at V5 and within the dorsal visual processing pathway. This neuromodulation significantly improved the performance of a motion-onset visual speller in a brain-computer interface.