Transcranial focused ultrasound for identifying the neural substrate of conscious perception

Identifying what aspects of brain activity are responsible for conscious perception remains one of the most challenging problems in science. While progress has been made through psychophysical studies employing EEG and fMRI, research would greatly benefit from improved methods for stimulating the brain in healthy human subjects. Traditional techniques for neural stimulation through the skull, including electrical or magnetic stimulation, suffer from coarse spatial resolution and have limited ability to target deep brain structures with high spatial selectivity. Over the past decade, a new tool has emerged known as transcranial focused ultrasound (tFUS), which enables the human brain to be stimulated safely and non-invasively through the skull with millimeter-scale spatial resolution, including cortical as well as deep brain structures. This tool offers an exciting opportunity for breakthroughs in consciousness research. Given the extensive preparation and regulatory approvals associated with tFUS testing, careful experimental planning is essential. Therefore, our goal here is to provide a roadmap for using tFUS in humans for exploring the neural substrate of conscious perception.