Researchers at MIT are exploring transcranial focused ultrasound, a noninvasive technology that can precisely stimulate deep regions of the brain that were previously off-limits. In a new "roadmap" paper, they explain how this method could finally let scientists test cause-and-effect in consciousness research, not just observe correlations. Transcranial focused ultrasound is noninvasive and reaches deeper into the brain, with greater resolution, than other forms of brain stimulation, such as transcranial magnetic or electrical stimulation. With transcranial ultrasound, researchers finally have a tool that will let them probe millimeter-scale structures in the human brain to understand their role in conscious perception. They are planning experiments in visual perception, where they use traditional experiments in visual psychophysics, but with the added capability of modulating specific neural structures during the visual testing to understand their role in conscious and subconscious processing.
Moving from watching the brain light up to actually touching it and seeing what happens is the difference between description and explanation.