Neuroscience study sheds light on how words are represented in the brain

July 20, 2016 by Joe Miksch
Credit: Wikimedia Commons

Reading is a relatively modern and uniquely human skill. For this reason, visual word recognition has been a puzzle for neuroscientists because the neural systems responsible for reading could not have evolved for this purpose. "The existence of brain regions dedicated to reading has been fiercely debated for almost 200 years," said Avniel Ghuman, an assistant professor in the University of Pittsburgh Department of Neurological Surgery. "Wernicke, Dejerine, and Charcot, among the most important and influential neurologists and neuroscientists of the 19th century, debated whether or not there was a visual center for words in the brain."

In recent years, much of this debate has centered on the left mid-fusiform gyrus, which some call the visual word form area. A recent study by Pitt neuroscience researchers addresses this debate and sheds light on our understanding of the neurobiology of reading.

In a study to be published July 19 in the Proceedings of the National Academy of Sciences, Ghuman, Elizabeth Hirshorn of Pitt's Learning Research and Development Center (LRDC), and colleagues from the Department of Psychology and Center for the Neural Basis of Cognition used direct neural recordings and brain stimulation to study the role of the visual word form area in reading in four epileptic patients. The patients chose for their drug-resistant epilepsy and volunteered to participate in the research study. As part of the surgical treatment, neurosurgeons implanted electrodes in the patients' visual word form area, providing an unprecedented opportunity to understand how the brain recognizes printed .

First, painless electrical brain stimulation was used through the electrodes to disrupt the normal functioning of the visual word form area, which adversely affected the patients' ability to read words. One patient dramatically misperceived letters, and another felt that there were words and parts of words present that were not in what she was reading. Stimulation to this region did not disrupt their ability to name objects or faces.

Credit: University of Pittsburgh

In addition to stimulating through these electrodes, the activity from the area was recorded while the patients read words. Using techniques from machine learning to analyze the brain activity that evolved over a few hundred milliseconds from this region, the researchers could tell what word a patient was reading at a particular moment. This suggests that neural activity in the area codes knowledge about learned visual words that can be used to discriminate even words that are only one letter different from one another (for example, "hint" and "lint").

"This study shows that the visual word form area is exquisitely tuned to the fine details of written words and that this area plays a critical role in refining the brain's representation of what we are reading. The disrupted word and letter perception seen with stimulation provides direct evidence that the visual word form area plays a dedicated role in skilled reading," said Hirshorn. "These results also have important implications for understanding and treating reading disorders. The activity in the visual word form area, along with its interactions with other brain areas involved in language processing, could be a marker for proficient reading. Having a better understanding of this neural system could be critical for diagnosing reading disorders and developing targeted therapies."

"It is exciting that with modern brain-recording techniques and advanced analysis methods, we are finally able to start answering questions about the and the mind that people have asked for centuries and contribute to our understanding of reading disorders," said Ghuman.

Explore further: In the brain, one area sees familiar words as pictures, another sounds out words

More information: Elizabeth A. Hirshorn et al. Decoding and disrupting left midfusiform gyrus activity during word reading, Proceedings of the National Academy of Sciences (2016). DOI: 10.1073/pnas.1604126113

Related Stories

In the brain, one area sees familiar words as pictures, another sounds out words

June 9, 2016
Skilled readers can quickly recognize words when they read because the word has been placed in a visual dictionary of sorts which functions separately from an area that processes the sounds of written words, say Georgetown ...

After learning new words, brain sees them as pictures

March 24, 2015
When we look at a known word, our brain sees it like a picture, not a group of letters needing to be processed. That's the finding from a Georgetown University Medical Center (GUMC) study published in the Journal of Neuroscience, ...

Key advance: Neuroscientists get a new look into how we read

April 7, 2016
Neuroscientists at UC Davis have come up with a way to observe brain activity during natural reading. It's the first time researchers have been able to study the brain while reading actual texts, instead of individual words, ...

Skilled readers rely on their brain's 'visual dictionary' to recognize words

November 14, 2011
Skilled readers can recognize words at lightning fast speed when they read because the word has been placed in a visual dictionary of sorts, say Georgetown University Medical Center (GUMC) neuroscientists. The visual dictionary ...

Concentrating on word sounds helps reading instruction and intervention

January 27, 2015
A neuroimaging study by a University at Buffalo psychologist suggests that phonics, a method of learning to read using knowledge of word sounds, shouldn't be overlooked in favor of a whole-language technique that focuses ...

Recommended for you

To forget or to remember? Memory depends on subtle brain signals, scientists find

November 22, 2017
The fragrance of hot pumpkin pie can bring back pleasant memories of holidays past, while the scent of an antiseptic hospital room may cause a shudder. The power of odors to activate memories both pleasing and aversive exists ...

What if consciousness is not what drives the human mind?

November 22, 2017
Everyone knows what it feels like to have consciousness: it's that self-evident sense of personal awareness, which gives us a feeling of ownership and control over the thoughts, emotions and experiences that we have every ...

Pitch imperfect? How the brain decodes pitch may improve cochlear implants

November 22, 2017
Picture yourself with a friend in a crowded restaurant. The din of other diners, the clattering of dishes, the muffled notes of background music, the voice of your friend, not to mention your own – all compete for your ...

New research suggests high-intensity exercise boosts memory

November 22, 2017
The health advantages of high-intensity exercise are widely known but new research from McMaster University points to another major benefit: better memory.

Now you like it, now you don't: Brain stimulation can change how much we enjoy and value music

November 20, 2017
Enjoyment of music is considered a subjective experience; what one person finds gratifying, another may find irritating. Music theorists have long emphasized that although musical taste is relative, our enjoyment of music, ...

MRI uncovers brain abnormalities in people with depression and anxiety

November 20, 2017
Researchers using MRI have discovered a common pattern of structural abnormalities in the brains of people with depression and social anxiety, according to a study presented being next week at the annual meeting of the Radiological ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.