This tool could show how consciousness works

A team led by MIT philosopher Matthias Michel and Lincoln Lab researcher Daniel Freeman has outlined a groundbreaking strategy to tackle one of science's hardest problems: consciousness. Their paper proposes using an emerging noninvasive technology called transcranial focused ultrasound (tFUS) to stimulate and study specific brain circuits. Unlike EEG or MRI, tFUS can send acoustic waves through the skull to focus on areas just a few millimeters wide, reaching deep brain structures with unprecedented precision for a noninvasive tool. This allows scientists to directly manipulate neural activity in targeted regions and observe the resulting effects on subjective experience.

The researchers' experimental framework aims to test two major competing theories of consciousness. The first, the "cognitivist" view, posits that conscious experience requires higher-level cognitive processes like reasoning or self-reflection, likely centered in the brain's frontal cortex. The opposing "non-cognitivist" theory suggests that specific, localized patterns of neural activity—potentially in subcortical structures or the back of the cortex—directly generate subjective feelings. By using tFUS to stimulate these different areas, scientists could see which manipulations reliably alter or extinguish conscious states, providing crucial empirical evidence in a field long dominated by philosophical debate. As Freeman states, this tool could help pinpoint the neural circuits responsible for sensations like pain or vision, and even complex human thought.