By activating their visual brain cortex, people who were born blind can describe
objects and even identify letters and words, with the proper stimulation and
using a device for sensory exchange developed by Hebrew University
The research team, headed by Prof. Amir Amedi of the Edmond
and Lilly Safra Center for Brain Sciences and Institute for Medical Research
Israel-Canada and including doctoral student Ella Streim- Amit, has just
published their findings in the journal Neuron; a summary of their research also
appeared in the journal Science.
They developed a unique training program
for seeing using the device, which transfers visual information to the blind via
their healthy senses.
The device translates pictures into tones; after a
few dozen hours of training, the blind from birth can identify images and put
them in visual categories such as faces, houses, parts of the body, ordinary
objects and textures.
They can also locate people, identify facial
expressions and read letters and words, thus being able to “see” enough to
exceed the World Health Organization minimum to be regarded as
Amedi said on Sunday that for decades, it is has been known that
if the visual cortex does not receive visual information after birth, it doesn’t
properly develop the normal visual structure and skills, and thus visual
reconstruction was thought to be impossible. But when the team checked what
happens in the brains of blind people who learned to “see” via sounds, their
visual cortex functioned even though they had learned to process images only
when they reached adulthood, he said.
The researchers also found that the
brains of the blind from birth had visual preferences similar to those with
normal sight when they reacted to different kinds of visual stimulation. For
example, the part of the brain used for reading showed that in the blind, as in
the sighted, there was increased activity in reaction to pictures of letters and
words. In addition, this region proved to be so flexible that one of the blind
people tested was able to react to such images after a two-hour training
“The brain of adults is more flexible that what we assumed,”
“These findings show it may be that the brains of blind
people, even for long periods, can ‘wake up’ to process vision through
rehabilitation, including new medical developments such as retinal implants
Additional research in the field by Amedi’s team with
Dr. Sheli Levi-Zedek that was published in the journal Restorative Neurology and
Neuroscience presented a device for sensory exchange. Using it, the blind from
birth could cover their eyes and still carry out rapid and exact movements
toward targets. Using a non-invasive device called “eye music” involving
pleasant music, the blind were able to “see” with sounds.
sessions of as little as half an hour, 18 blind from birth people were able to
tell the difference between a red or a green apple.
This paves the way
for future hybrid devices, including a receptor implanted in the eye together
with “eye music.”