The Visionary Genius Who Allowed Blind People See Through the Brain —
Paul Bach-y-Rita

“We see with our brain, not with our eyes” – Paul Bach-y-Rita

Seeing with the brain, not with the eyes. Hearing with the brain, not with the ears.
This simple principle led neuroscientist Paul Bach-y-Rita to pioneer sensory substitution, showing that the brain can reorganize itself and replace a lost sense with another. His work in neuroplasticity enabled blind people to ‘see’ through the brain and helped patients with balance disorders to walk normally.

The starting point: a family experience

In 1959, Paul’s father suffered a severe stroke that paralyzed half of his body and damaged his ability to speak. Doctors said he would never walk or talk normally again.
Paul and his brother George refused to accept this prognosis. They began an intensive, improvised rehabilitation program at home, based on re-learning basic tasks step by step — much like teaching a child.
If their father could not walk, they taught him to crawl first, then kneel, then stand. They applied the same approach to speech and other lost abilities. After three years, Paul’s father regained the ability to walk, speak, and live normally.
At the time, the dominant belief in medicine was that the brain had fixed, specialized areas and that once damaged, functions were permanently lost. The surprise came after his father’s death: the autopsy revealed massive “irreversible” damage to a large portion of his brainstem. Yet he HAD recovered.
Paul Bach-y-Rita realized that the brain was not fixed at all. It could reorganize itself by forming new neural connections to restore lost functions.

Neuroplasticity vs. Localizationism

Although the idea of a “plastic” brain had been described as early as 1890, it was not widely accepted. The dominant view was localizationism: the brain was thought to be divided into rigid areas, each responsible for a specific function.
While it is true that certain regions are specialized, Bach-y-Rita showed that many functions can reroute through new pathways — just as happened in his father’s recovery and that the brain is actually “plastic”.

The idea: sensory substitution devices

This insight became the foundation of Bach-y-Rita’s most important discovery: sensory substitution.
He emphasized that sensory information does not depend on the organ delivering the signal, but on where the signal is processed in the brain. A light is not “seen” because of the eye, but because the visual cortex interprets it.
So if the brain “sees” through the visual cortex, then any signal routed to that area could create a visual-like perception. A camera could potentially replace the eyes, just as a microphone could replace the ears — if the information is converted into a form the brain can interpret.

Vision through touch

This idea led to the creation of the first machine that allowed blind people to “see.”
Bach-y-Rita used a camera connected to a dentist’s chair fitted with 400 small vibrating plates placed against the user’s back. The camera converted visual images into patterns of vibration — like tactile pixels.
It works like when someone draws a shape on your back and you can tell what it is — even though your eyes aren’t involved. The brain can use information from the skin as if it were coming from the eyes.
With training, users learned to recognize shapes, perceive movement, and even sense objects approaching the camera and describe their arrangement in three-dimensional space.
The resulting perception wasn’t identical to natural vision, but Bach-y-Rita used a powerful analogy: it was like walking in the dark and recognizing a building from its outline. It may not be detailed, but is that a reason not to call it vision?
For the first time in history, blind participants could recognize objects and shapes through patterns of touch.
Later, the heavy vibrating back-plates was replaced by a thin array of electrodes placed on the tongue.
The tongue proved ideal: highly sensitive, densely innervated, and naturally moist, which improves electrical conductivity.
This breakthrough opened the door to new applications.

Transposing the idea to other senses: restoring balance

What worked for vision — though with limitations such as low resolution and long training — worked exceptionally well for people with balance disorders.
These patients had damage to their vestibular apparatus, the sensory system responsible for our sense of orientation in space. The vestibular system consists of three semicircular canals in the inner ear that detect motion in three dimensions. Tiny hair cells send signals to the brain, which then instructs our muscles how to maintain posture so we don’t fall.
Bach-y-Rita created a device connecting a hat equipped with accelerometers to an array of electrodes on the tongue. The accelerometers detected the direction and speed of head movement and converted that information into patterns of stimulation.
After training, patients learned to interpret these patterns and automatically adjust their posture. The most extraordinary part: over time, many regained their balance even without the device, showing that the brain had learned an entirely new pathway.

Implications in today’s world

In 1998, Bach-y-Rita founded the company Wicab, which continues to develop the BrainPort Vision Pro: a vision-aid headset with a camera, controls, a battery, and the tongue-array system.
Today, his work inspires researchers and companies developing sensory-substitution devices to help blind people see, deaf people hear, and patients with vestibular loss regain balance.
He demonstrated that it is possible to use one sense to provide information normally delivered by another, paving the way for modern sensory prosthetics.
Beyond his scientific achievements, Paul Bach-y-Rita was a visionary — decades ahead of his time, often misunderstood, and not as celebrated as he should be.

📖 References:

• Bach-y-Rita et al. (1969). Vision Substitution by Tactile Image Projection. Nature.
• Doidge, N. The Brain That Changes Itself. Penguin Books.
• Tyler, M. et al. Form perception with a 49-point electrotactile stimulus array on the tongue. ResearchGate PDF.
• Wicab Inc. BrainPort Vision Pro. https://www.wicab.com/brainport-vision-pro
• MIT CMS. Champagne for the Blind: Paul Bach-y-Rita, Neuroscience’s Forgotten Genius. PDF.