[Nfbf-l] Activating the 'mind's eye' - sounds, instead of eyesight can be alternative vision

[Alan Dicey]

Activating the 'mind's eye' - sounds,instead of eyesight can be alternative 
vision

Seeing with Sound - The vOICe
http://www.seeingwithsound.com/winvoice.htm

Activating the 'mind's eye' - sounds, instead of eyesight can be alternative 
vision.
Show Hebrew Univeristy researchers.
Jerusalem, Nov. 7, 2012  -
Common wisdom has it that if the visual cortex in the brain is deprived of 
visual information in early infanthood, it may never develop properly its 
functional specialization, making sight restoration later in life almost 
impossible.
Scientists at the Hebrew University of Jerusalem and in France have now 
shown that blind people - using specialized photographic and sound 
equipment - can actually "see" and describe objects and even identify 
letters and words.
The new study by a team of researchers, led by Professor Amir Amedi of the 
Edmond and Lily Safra Center for Brain Sciences and the Institute for 
Medical Research Israel-Canada at the Hebrew University and Ph.D. candidate 
Ella Striem-Amit,  has demonstrated how this achievement is possible through 
the use of a unique training paradigm, using sensory substitution devices 
(SSDs).
SSDs are non-invasive sensory aids that provide visual information to the 
blind via their existing senses. For example, using a visual-to-auditory SSD 
in a clinical or everyday setting, users wear a miniature camera connected 
to a
small
computer (or smart phone) and stereo headphones.

The images are converted into "soundscapes," using a predictable algorithm,
allowing the user to listen to and then interpret the visual information
coming
from the camera. The blind participants using this device reach a level of
visual acuity technically surpassing the world-agreed criterion of the World
Health Organization (WHO) for blindness, as published in a previous study by
the
same group.

The resulting sight, though not conventional in that it does not involve
activation of the ophthalmological system of the body, is no less visual in
the
sense that it actually activates the visual identification network in the
brain.

The study shows that following a dedicated (but relatively brief) 70 hours
of
unique training paradigm developed in the Amedi lab, the blind people could
easily use SSDs to characterize images into object categories, such as
images of
faces, houses, body shapes, everyday objects and textures. They could also
identify even more complex everyday objects - locating people's positions,
identifying facial expressions, and even reading letters and words (for
demos,
movies and further information: http://brain.huji.ac.il/).

These unprecedented behavioral results are reported in the current issue of
the
prestigious neuroscience journal, Neuron.

The Hebrew University study went on further to actually test what happens in
the
brain when the blind learn to see with sounds. Specifically, the group
tested
the ability of this high-acuity vision to activate the supposedly dormant
visual
cortex of the blind, even though it was taught to process the visual images
through sounds only in adulthood.

Prof. Amedi, and Ella Striem-Amit used functional magnetic resonance imaging
(fMRI) to measure the neural activity of people blind from birth as they
"saw"
- using the SSD - high-resolution images of letters, faces, houses, everyday
objects and body-shapes. Surprisingly, not only was their visual cortex
activated by the sounds, their brain showed selectivity for visual
categories
which characterize the normally developing, sighted brain.

A specific part of the brain, known as the Visual Word Form Area, or VWFA -
that was first discovered in sighted people by Profs. Laurent Cohen and
Stanislas Dehaene of Pitie-Salpétriere Hospital-INSERM-CEA, of France,
co-authors of the current article - is normally very selective.

In sighted people, it has a role in reading, and is activated by seeing and
reading letters more than by any other visual object category.
Astonishingly,
the same was found in this area in people deprived of sight. Their VWFA,
after
only tens of hours of training in SSD use, showed more activation for
letters
than for any of the other visual categories tested.

In fact, the VWFA was so plastic to change, that it showed increased
activation
for SSD letters after less than two hours of training by one of the study
participants.

"The adult brain is more flexible that we thought," says Prof. Amedi. In
fact,
this and other recent research from various groups have demonstrated that
multiple brain areas are not specific to their input sense (vision, audition
or
touch), but rather to the task, or computation they perform, which may be
computed with various modalities. (This information was summarized in a
recent
review by the Amedi research group published in the journal Current
Directions
in Neurology.)

All of this suggests that in the blind, brain areas might potentially be
"awakened" to processing visual properties and tasks even after years or
maybe
even lifelong blindness, if the proper technologies and training approaches
are
used, says Amedi.

The findings also give hope that reintroduced input into the visual centers
of
the blind brain could potentially restore vision, and that SSDs might be
useful
for visual rehabilitation.

"SSDs might help blind or visually-impaired individuals learn to process
complex
images, as done in this study, or they might be used as sensory interpreters
that provide high-resolution, supportive, synchronous input to a visual
signal
arriving from an external device such as bionic eyes" says Prof. Amedi.

Source URL:
http://www.eurekalert.org/pub_releases/2012-11/thuo-at110712.php

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