March 13th, 2011 Posted by Wendy Greif, Literacy News
This is Dr. Amir Amedi of the Hebrew University of Jerusalem
It doesn’t matter if readers use sight or Braille; the portion of the brain responsible for visual reading reacts exactly alike. According to new research from the Hebrew University of Jerusalem and France, brain imaging studies of blind people show activity in precisely the same part of the brain that lights up when people use vision to read.
Presented in the journal Current Biology, the study revealed that regardless of sensory input, the brain doesn’t distinguish blind people reading Braille from sighted readers. Dr. Amir Amedi’s team used functional magnetic resonance imaging (fMRI) to measure the neural activity in people who had been blind since birth while they read Braille. Researchers were interested in studying a very specific part of the brain, known as the Visual Word Form Area, or VWFA, which shows peaks of activity when studying sighted readers. The results were surprising.
Brain activity in blind and sighted readers showed identical patterns in the VWFA—in fact they were indistinguishable. The main functional properties of the VWFA were identical in both types of readers, requiring no visual experience at all. “To the best of our judgment, this provides the strongest support so far for the metamodal theory of brain function,” said Dr. Amir Amedi of the Hebrew University of Jerusalem, who spearheaded the research team.
This suggests that brain regions are task-oriented and defined by the computations they perform. These findings challenge the textbook notion that the brain processes information in divided regions that are specialized for different senses, including touch and sight. As it turns out, that’s not the case. “The brain is not a sensory machine, although it often looks like one; it is a task machine,” said Amedi.
Most tasks the brain performs have been innately ingrained, unlike reading, which is a relatively new invention by comparison—only about 5,400 years old. An even newer task, Braille has been around for 200 years. “That’s not enough time for evolution to have shaped a brain-module dedicated to reading,” Amedi explained. VWFA is a multisensory integration area that binds simple features into more elaborate shape descriptions making it ideal for the relatively new task of reading.
Researchers say that its specific anatomical location and strong connectivity to language areas enable it to bridge a high-level perceptual word representation and language-related components of reading. Consequently, it’s the most suitable region to be taken over during reading acquisition—even when reading by touch without prior visual experience.
Up next for Amedi and his research associates is an examination of brain activity as people learn to read Braille for the first time. How rapidly does this takeover happen? How does the brain change to process information in words? Is it instantaneous? This study should answer these questions and shed even more light on how the human brain tackles a challenging task.