Merge Labs spun out of Forest Neurotech in January, with Norman and Aflalo among the company’s cofounders, which also include Altman, researcher Mikhail Shapiro, and tech entrepreneurs Alex Blania and Sandro Herbig.
Maryam Shanechi, a neuroengineer at the University of Southern California, says because ultrasound measures brain activity indirectly from blood instead of directly from neurons, there is a natural delay of a few seconds between when neurons fire and the subsequent change in blood flow and volume.
“It captures a slower variation in neural activity,” Shanechi says. “That’s fine for a lot of applications, but it depends what you want to build.”
For real-time, fast-paced tasks such as moving a robotic limb instantly or rapid typing, this lag time could pose a challenge for ultrasound-based brain-computer interfaces. Bridge is planning to use predictive AI models to cut down on that lag time and boost the performance of its interface. Biederman says the company is interested in pursuing both consumer and medical applications but didn’t comment on specific plans.
The company is starting its first clinical study in volunteers in Redwood City, California. It’s an observational study, with no treatments or diagnoses involved, in which a small ultrasound probe will be placed on the side of the head of healthy adults, as well as those who have undergone skull surgery. Bridge’s probes, which use semiconductor silicon chips made by the portable ultrasound company Butterfly Network, will record brain activity while participants listen, watch, move, and speak.
Bridge isn’t releasing images of its device yet, but Biederman says it is “something close to headphones” that will sit on the temporal window, which is located slightly above the ear. As the thinnest part of the skull, “it’s the easiest place to image through,” Biederman says. That’s relevant for ultrasound, because bone scatters and absorbs sound, which presents technical challenges for imaging noninvasively through the skull.
In a 2024 study, researchers from Caltech and the University of Southern California demonstrated that an ultrasound-based brain-computer interface could read and decode human brain activity, but it required a portion of the skull to be removed and replaced with a “window” through which ultrasound waves can pass. That is one of the biggest technical hurdles that Bridge will have to address.
“My vision is focused on noninvasive interfaces,” Biederman says. “I think that’s where the biggest opportunity to help people is.”
