Neuropsychologist proves that some blind people 'see' with their ears

Mar 16, 2011

Dr. Olivier Collignon of the University of Montreal's Saint-Justine Hospital Research Centre compared the brain activity of people who can see and people who were born blind, and discovered that the part of the brain that normally works with our eyes to process vision and space perception can actually rewire itself to process sound information instead.

The research was undertaken in collaboration with Dr Franco Lepore of the Centre for Research in and Cognition and was published late yesterday in the .

The research builds on other studies which show that the blind have a heightened ability to process sounds as part of their space perception. "Although several studies have shown occipital regions of people who were born blind to be involved in nonvisual processing, whether the functional organization of the observed in sighted individuals is maintained in the rewired occipital regions of the blind has only been recently investigated," Collignon said. The visual cortex, as its name would suggest, is responsible for processing sight. The right and left hemisphere of the brain have one each. They are located at the back of the brain, which is called the occipital lobe. "Our study reveals that some regions of the right dorsal occipital stream do not require to develop a specialization for the processing of spatial information and are functionally integrated in the preexisting brain network dedicated to this ability."

The researchers worked with 11 individuals who were born blind and 11 who were not. Their was analyzed via MRI scanning while they were subjected to a series of tones. "The results demonstrate the brain's amazing plasticity," Collignon said. Plasticity is a scientific term that refers to the brain's ability to change as a result of an experience. "The brain designates a specific set of areas for spatial processing, even if it is deprived of its natural inputs since birth. The visually deprived brain is sufficiently flexible that it uses "neuronal niche" to develop and perform functions that are sufficiently close to the ones required by the remaining senses. Such a research demonstrates that the brain should be more considered as a function-oriented machine rather than a pure sensory machine".

The findings raise questions regarding how this rewiring occurs during the development of blind new born babies. "In early life, the brain is sculpting itself on the basis of experience, with some synaptic connections eliminated and others strengthened," Collignon noted. Synaptic connections enable our neurons, or cells, to communicate. "After a peak of development ending approximately at the age of 8 months, approximately 40% of the synapses of the visual cortex are gradually removed to reach a stable synaptic density at approximately the age of 11 years. It is possible that that the rewiring occurs as part of the maintenance of our ever changing neural connections, but this theory will require further research," Collignon said.

Explore further: Worry, jealousy, moodiness linked to higher risk of Alzheimer's in women

Related Stories

Parts of brain can switch functions: study

Feb 28, 2011

(PhysOrg.com) -- When your brain encounters sensory stimuli, such as the scent of your morning coffee or the sound of a honking car, that input gets shuttled to the appropriate brain region for analysis. The ...

The brain as a 'task machine'

Feb 17, 2011

The portion of the brain responsible for visual reading doesn't require vision at all, according to a new study published online on February 17 in Current Biology. Brain imaging studies of blind people as they read words ...

Younger brains are easier to rewire

Oct 21, 2010

About a decade ago, scientists studying the brains of blind people made a surprising discovery: A brain region normally devoted to processing images had been rewired to interpret tactile information, such as input from the ...

Recommended for you

What happens in our brain when we unlock a door?

13 hours ago

People who are unable to button up their jacket or who find it difficult to insert a key in lock suffer from a condition known as apraxia. This means that their motor skills have been impaired – as a result ...

Sport can help multiple sclerosis patients

17 hours ago

A study developed at the Miguel Hernández University of Elche (Spain) has preliminarily concluded that people with multiple sclerosis may reduce perceived fatigue and increase mobility through a series of ...

Obama's BRAIN initiative gets more than $300 million

21 hours ago

President Barack Obama's initiative to study the brain and improve treatment of conditions like Alzheimer's and autism was given a boost Tuesday with the announcement of more than $300 million in funds.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

jselin
not rated yet Mar 16, 2011
I'm not suprised the spatial functions are independant of vision... blind people still have to know which drawer the silverware is in, which hallway to turn down, etc, etc. Vision is nice but I wouldn't expect it to be the sole basis of our spatial awareness.