One way we study fear learning is through Pavlovian fear conditioning, a well-established method used in animal research to understand the brain circuits and mechanisms involved. This research has consistently found that the amygdala plays a key role in fear learning. However, our understanding of fear learning in humans is mainly based on neuroimaging studies, which can only provide correlations and not causality. Therefore, we will use TUS in combination with fear conditioning procedures to causally test the amygdala's role in fear learning in humans. Previous research has shown that TUS can modulate amygdala activation in non-human primates and cognitive processes in humans by neuromodulating deep brain structures, so we expect TUS to modulate amygdala-dependent fear learning in humans.