Bridge Neurotech raises $13.5 million to build a brain-computer interface without surgery

By Inside BCI · October 8, 2026

“BCIs exist today, but they require a hole in your head,” wrote Will Biederman, whose company, Bridge Neurotech, came out of stealth on 6 October. He puts the number of people who have received an implanted brain-computer interface at around one hundred. Bridge has raised $13.5 million to build one that stays outside the head and reads the brain with sound, and it has signed a deal to license Butterfly Network’s ultrasound-on-chip technology.

What Bridge is building

Bridge works with functional ultrasound imaging. A probe sends rapid pulses of sound into the brain and listens to the echoes. Echoes from still tissue repeat from pulse to pulse, while echoes from moving red blood cells change. When a region of the brain becomes active, its blood vessels widen and that moving-blood signal rises, so the images show which areas are working and when. Like an fMRI scanner, it reads brain activity indirectly, through the blood supply. Bridge wants to capture the signal from a device a person can wear, and to decode it with AI models.

Two problems stand in the way, Bridge says. The skull scatters and absorbs sound, and does so differently in every person. And the images have to be decoded into meaning in real time, by models that work across different people. The company says it is early and that neither problem has a single answer.

Why the first study recruits people with skull implants

Bridge’s first research study is observational and approved by an independent review board. It is enrolling two groups in Redwood City, California. The first is healthy adults, where the aim is to image the brain through the intact skull. The second is adults who had part of the skull removed after a stroke, injury or surgery, and repaired at least three months earlier with a PEEK implant or a Longeviti implant, both of which let sound through more easily than bone. Their recordings give Bridge a reference against which to judge what it measures through bone. Each participant gets a light 3D-printed helmet that holds the probe against the side of the head, or over the implant, while they listen, watch, move or speak on cue.

A 2024 study in Science Translational Medicine showed the principle. Researchers led by Caltech, working with neurosurgeons at the University of Southern California, imaged and decoded brain activity in one patient through a custom skull implant built to let ultrasound pass. Sumner Norman, now a Merge Labs co-founder, helped design that implant.

The founder and his history with Butterfly

Biederman has built neural hardware before. Bridge says the brain-implant chips he designed during his PhD at the University of California, Berkeley became Neuralink’s first chip. He then spent about a decade at Google X and Verily. He co-founded Forest Neurotech, a nonprofit ultrasound research group set up inside Convergent Research, with Norman and Tyson Aflalo, and led the engineering of its Forest 1 ultrasound system. Forest has since been renamed Arbor Neuroscience.

Biederman’s work with Butterfly goes back three years. In October 2023, with Biederman as its chief technology officer, Forest signed a five-year co-development agreement worth $20 million to Butterfly in licensing fees, chip purchases, services and milestone payments.

Norman and Aflalo went on to co-found Merge Labs with Sam Altman and others. Merge launched in January with a $252 million seed round backed by OpenAI, and on 1 September it named Butterfly its exclusive partner for chip-based ultrasound. Bridge’s $13.5 million is about a nineteenth of Merge’s seed.

The round was backed by General Catalyst, reMind Capital, Sunflower Capital and Scott Sandell, executive chairman and chief investment officer of New Enterprise Associates. Oxford Seed Fund, Position Ventures and TreeHub are also listed among Bridge’s investors. Its advisers include Alexander Huth of UC Berkeley, who models how the brain represents language; Gianmarco Pinton of the University of North Carolina at Chapel Hill and North Carolina State University, who works on ultrasound physics and imaging; and Ashwin Ramayya, a Stanford neurosurgeon.

What Butterfly gets

Bridge will license Butterfly’s Ultrasound-on-Chip technology through Butterfly Embedded, the unit that licenses the semiconductor ultrasound platform behind Butterfly’s handheld iQ3 probe to other companies. The multi-year agreement includes payments for technology access and development milestones and commitments to buy Butterfly hardware. Neither company disclosed its value. Butterfly expects royalties on future commercial sales under the Merge deal. Any royalty terms with Bridge have not been disclosed.

When Butterfly signed Merge, it kept the right to license the same technology to other companies in the field. Three of its brain-computer interface deals now trace to the founders of one research group: Forest in 2023, Merge in September and Bridge in October. Each deal brings Butterfly licence fees and hardware purchase commitments without building a brain-computer interface of its own.

The race is international. In China, Gestala closed a US$62 million Angel+ round in July and BCI-Sonics a RMB 200 million Pre-A round in September, both for ultrasound-based brain-computer interfaces.

Not disclosed

Bridge has not named a lead investor or disclosed its valuation. Nor has it disclosed the value of the Butterfly agreement, any royalty terms, or which Butterfly chip family it will use. It has not said how many people its study will enrol, when it expects results, which medical or consumer use it will pursue first, or which regulatory route it will take.

What to watch

Whether Bridge shows brain activity imaged and decoded through the intact skulls of healthy adults, the result its cranioplasty group is designed to benchmark.

Whether Bridge names a first use, medical or consumer, and a regulatory route.

Whether Butterfly signs further brain-computer interface licensees, or discloses what the deals are worth.

Whether Merge Labs publishes human data from its own ultrasound system.

Sources

Primary:

Coverage:

Cross-reference to prior InsideBCI coverage:

market Bridge-Neurotech Will-Biederman Butterfly-Network BFLY Butterfly-Embedded Ultrasound-on-Chip functional-ultrasound fUSI non-invasive-BCI ultrasound-BCI Merge-Labs Forest-Neurotech Arbor-Neuroscience General-Catalyst funding