Calling Mr. Webster: We need a new definition for the verb "to see."
Recently, NPR's podcast Invisibilia explored how Daniel Kish, a blind man, uses echolocation to create mental pictures of the world around him. Kish and his skills are not only very impressive, they also remind us that our understanding of what it means to "see" is so yesterday. In fact, brain scans of those who are visually impaired have revealed that they "see" (or, perhaps more accurately, use their senses) in much the same way as everyone else.
How is this possible? It's easy to believe that sight works exclusively by taking in information through the eyes, which is then interpreted by the brain. But a study published in Cell Press challenges that notion. In 2011, researchers from Hebrew University in Jerusalem looked at brain scans of eight people who had been blind since birth as they read braille. The researchers expected that using one's fingertips to read might activate a different part of the brain than does reading with one's eyes.
Au contraire. Instead, they found that, whether you are reading with your eyes or with your hands, the same part of the brain is activated. This is big. Turns out that the brain might not be as focused around specific senses as we once thought.
Read away. Researchers now know that brain activity associated with reading isn't all that different between people who use their fingers, and those who use their eyes.
Think of the brain like a house, and neurons like the furniture that fills up each room. Say the living room is the designated place for reading. Even if you were to move some of the furniture out of that room and into another, people will still go to the living room to read. Essentially, the study suggests that our brains have a set infrastructure and that the neurons that relay our senses are as movable as pieces of furniture — that is, they can come from places as disparate as our eyes and our fingertips.
What this means for mapping the brain: The theory typically goes like this: When someone loses one sense, such as sight, their other senses, such as hearing or smell, get stronger. But more and more research supports the idea that the brain actually rewires the connections from the lost sense to other regions of the brain. This reorganization, known as neuroplasticity, is what helps us to recover from injuries or adjust to new environments. To go back to the house analogy, it's like taking all the furniture from one room and finding a way to accommodate it in another.
"In the absence of vision, the world is experienced as sequences," neurobiologist Ehud Zohary of Hebrew University in Jerusalem told Live Science. While that might be a difficult concept for someone who can see to grasp, it could serve as an indicator that perhaps we are approaching brain research with too narrow a concept of what it means to see, hear, smell, taste or touch. Quite a big deal considering learning the senses is one of the very first lessons in preschool.
- What part of the brain is activated in Braille?
- How do blind people know where the brain is?
- How do you read Braille with your fingers?
- How do blind people process information?
- How does the age of onset of blindness affect your sense of touch?
parietal regions
As in sighted reading, Braille reading also activates parietal regions involved in the allocation of spatial attention, including the left intraparietal sulcus and bilateral superior parietal lobule (Sadato et al., 1996; Burton et al., 2002).
Which body part do the blind people use to read through Braille?
“The brain is not a sensory machine, although it often looks like one; it is a task machine,” said Amir Amedi of The Hebrew University of Jerusalem. “A brain area can fulfill a unique function, in this case reading, regardless of what form the sensory input takes.”
What do brain scans reveal about visually impaired people who learn to read Braille by touch early in life?
The text states that brain scans reveal that when visually impaired people learn Braille early in life, brain areas specialized for vision become active, suggesting that they become involved in processing touch sensations.
How do blind people know where the brain is?
By producing clicks with their mouths and listening for the echoes, blind people can locate objects in their surroundings. This ability is tightly linked with the brain activity in the visual cortex.
Which receptors are used in Braille?
Receptors terminating in Merkel cells are found near the surface of the skin, and have an excellent spatial resolution, with an ability to resolve stimuli separated by as little as 0.5 mm in glabrous skin [6]. Merkel receptors are the primary receptors that are used in reading Braille.
How is Braille processed?
This process involves converting simple tactile information into meaningful patterns that have lexical and semantic properties. The perceptual processing of Braille might be mediated by the somatosensory system, whereas visual letter identity is accomplished within the visual system in sighted people.
How do you read Braille with your fingers?
Try using your middle finger or pinky instead of your index finger and see which finger is best in identifying the writing. Extra: You can also read braille with two hands. Braille readers use the index fingers of both the left and right hands simultaneously to reduce their reading time.
What is Braille font?
Viewing braille dots on a computer On screen a braille font is used to indicate where braille dots or characters would appear in a document when later embossed. The fonts display as filled dots simulating where the raised dots would be.
What happens to neurons in visual cortex in individuals who become blind?
“We found that the visual cortex in the blind was much more strongly activated than it was in the sighted, where visual cortex was mostly deactivated by sounds and touch,” Rauschecker says. “Furthermore, there was a direct correlation between brain activity and performance in the blind.
How do blind people process information?
For blind people who are adept at echolocation, sound information routes through the visual cortex as well. Scans with functional magnetic resonance imaging (fMRI) showed activity in areas of their brains associated with visual processing.
Do blind people dream in color?
Public Domain Image, source: NSF. Yes, blind people do indeed dream in visual images. For people who were born with eyesight and then later went blind, it is not surprising that they experience visual sensations while dreaming. For this reason, he can dream in visual images.
How are blind people able to read Braille?
Skilled readers use both hands for reading Braille, with a variety of methods in evidence (see Davidson, Appelle & Haber, 1992). Some blind people use their right index finger to smoothly and rapidly scan lines of text and the left index finger for finding the beginning of the next line.
How does the age of onset of blindness affect your sense of touch?
The age of onset of blindness has implications for how well people use their sense of touch. For example, if people are Congenitally Blind (CB), that is, born without sight or lose it soon after birth, they will not benefit from visual experience or visual imagery. However, they may have an advantage conveyed by their education in mobility skills.
How does the sense of touch help the blind?
Blind individuals rely on their sense of touch for pattern perception, much as the rest of us depend on vision. If a blind person has extra training in the use of touch for tasks such as Braille or spatial orientation, then we might expect increased skill as a consequence.
Is the sensory acuity of the Blind a form of adaptation?
Several studies supported the sensory compensation hypothesis, suggesting that the superior tactile spatial acuity in the blind may be a form of adaptation (e.g., Sathian, 2000; Van Boven, Hamilton, Kauffman, Keenan, & Pascual-Leone, 2000).