Functional ultrasound

Using high-frame-rate ultrasound to image brain activity through blood-flow changes, or focused ultrasound to modulate it.

• It fires thousands of flat ultrasound pulses a second to detect tiny changes of blood flow in small vessels, which track neural activity.
• Resolution is around a tenth of a millimetre, finer than functional MRI, and it reaches deep structures that light-based methods can't.
• Focused ultrasound can also excite or quiet targeted regions without surgery, and is being studied for depression and other disorders.
• The adult skull strongly distorts sound, so imaging usually needs a skull opening or window, and wearable devices are at an early stage.