[Nfbf-l] Scans reveals that those with no sight can still tell if a bulb is switched on

[Alan Dicey]

Dear Friends,,
I found the below article very interesting.
With Best Regards,
God Bless,
Alan
Plantation, Florida

Subject: ARTIKEL

Light activates the brain in BLIND people: Scans reveals that those with no 
sight can still tell if a bulb is switched on
During tests, blind people identified when lights had been switched on Scans 
also found the change in light activated parts of their brains Researchers 
discovered light is registered by a part of the retina that is separate from 
the rods and cones that control sight
This suggests certain functions remain even when people lose their vision
In what has the potential to revolutionise how scientists and doctors treat
blindness, researchers have discovered that light not only activates the
brain, it does so even in people who can't see.
Research from the University of Montreal found that even when vision is
impaired and objects can no longer be seen, changes in light still register
in the brain and blind people can tell when a light is switched on or off.
This is because the light is picked up by a part of the retina in the eye
that is separate from the rods and cones that control overall vision.

Researchers from the University of Montreal said they were 'stunned' to
discover blind people can tell when a light has been turned on and off. The
study found that light is detected by a part of the retina that is separate
from the rods and cones people use to see objects
HOW DOES THE BRAIN REGISTER LIGHT WITHOUT SIGHT?
The retina is the back part of the eye that contains cells which respond to
light.
These cells are called photoreceptors and there are two types: rods and
cones.
The rods are most sensitive to changes in light, shape and movement and have
only one type of light-sensitive pigment.
Cones are not as sensitive to light as the rods, but are more sensitive to
colours.
Cones only work in bright light which is why people can't see colour clearly
in the dark.
Blindness is, in part, caused by the rods and cones not working correctly.
Researchers from Montreal University used brain scans to discover that an
additional photoreceptor, found in the ganglion cell layer of the retina,
also responds to light.
This is separate from the rods and cones, meaning that its function is not
affected when vision becomes impaired.
'We were stunned to discover that the brain still responded significantly to
light in these rare three completely blind patients despite having
absolutely no conscious vision at all,' said study author Steven Lockley.
Researchers put three blind people in a room and asked them to say whether
the light in the room was turned on or off. In all cases, the participants
were able to identify changes in light.
'We found the participants did indeed have a non-conscious awareness of the
light - they were able to determine correctly when the light was on without
being able to see it,' said author Gilles Vandewalle.
The researchers then flashed lights directly at the participants' eyes to
study more closely what impact the light had on the brain.
'The objective of this second test was to determine whether the light
affected the brain patterns associated with attentiveness - and it did,'
said researcher Olivier Collignon.
Finally, the participants were put into a functional MRI (fMRI) brain
scanner and each took part in a sound matching task while lights were
flashed in their eyes.
'The fMRI further showed that during an auditory working memory task, less
than a minute of blue light activated brain regions important to performing
the task,' continued Vandewall.
'These regions are involved in alertness and cognition regulation as well
being as key areas of the default mode network.'

The participants were put into a MRI brain scanner, similar to the one in
this stock image, and took part in a simple sound matching task while lights
were flashed in their eyes. The scans further showed that blue light
activated brain regions in the blind participants
Theses scans found the brain 'sees,' or detects light through a
photoreceptor found in the ganglion cell layer of the retina. This receptor
is separate from the rods and cones that control vision and help people see.
The study claims that the default network in the brain is linked so humans
use 'a minimal amount of resources' when monitoring their surroundings.
'If our understanding of the default network is correct, our results raise
the intriguing possibility that light is key to maintaining sustained
attention,' said agreed the researchers.
'This theory may explain why the brain's performance is improved when light
is present during tasks.'
Lockley concluded: 'Light doesn't just allow us to see, it tells the brain
whether it's night or day which in turn ensures our physiology, metabolism
and behaviour are synchronised with environmental time'.
'For diurnal species like ours, light stimulates day-like brain activity,
improving alertness and mood, and enhancing performance on many cognitive
tasks,' explained researcher Julie Carrier.
The research could have far-reaching effects in the treatment of blind
people, as well as in other cognitive disorders, because doctors can
potentially use light to activate specific parts of the brain.
The researchers from University of Montreal also worked with teams at
Boston's Brigham and Women's Hospital. Findings are reported in the Journal
of Cognitive Neuroscience Science.
DR. FRANS MOOLMAN
          MOBILITY SPECIALIST






_______________________________________________
Blind mailing list