Reading center in the brain builds a word filter
Recognizing words is the basis of understanding the meaning of a text. When we read, we move our eyes very efficiently and fast from word to word. Generally, this flow is only interrupted when we encounter an unfamiliar word. Using functional magnetic resonance imaging (fMRI), an international team of scientists at the University of Vienna and Goethe University Frankfurt discovered that the distinction of familiar words and unfamiliar strings of characters, in the sense of a filtering process, also serves well as a model for the patterns of brain activity which are observed during reading. This filter is located in the lower left temporal lobe, a brain area which is important for the visual word recognition. These results were recently published in PLOS Computational Biology.
Woman reads a book © pexels / Andrea Piacquadio
Bernstein member involved: Christian Fiebach
„Script and writing is and will remain an important information technology”, says Benjamin Gagl, former Postdoc at the Institute for Linguistics at the University of Vienna and the Institute for Psychology at Goethe University Frankfurt. With an international team under the lead of Christian Fiebach, Gagl investigated the cognitive and neuronal processes of word recognition. The researchers soon realized that psychological theories don’t make sufficiently precise assumptions on the exact function of the lower left temporal lobe, one of the most activated brain areas in word recognition studies.
Word filters as component for efficient reading
To close this knowledge gap, Gagl and colleagues developed a model that uses established behavioral findings from psychology to predict intensity of activation of this reading area in the brain. The model assumes that this brain area separates familiar and unfamiliar or meaningless words in the sense of a filter. Only familiar words would pass this filter for further processing. Unfamiliar words are often encountered when we learn something new. Thus, they require a different kind of processing in the brain.
This “lexical classification model“ can describe the reading behavior of subjects very well, and also give very precise predictions on brain activity, as Gagl and Fiebach’s team showed in three fMRI experiments. Furthermore, they were able to show in a behavioral study that reading performance is enhanced when the subjects explicitly train this filtering process. This way the researchers were able to identify, localize and describe a novel brain process which is at the core of reading activity.
Computer models as components for exact brain research
For their study, the researchers around Gagl and Fiebach combined methods from brain research and computational modelling. This combination allowed for the first time the precise prediction of activity patterns in the lower left temporal lobe. A major part in this study is that three fMRI studies were able to show that the model predicted the brain activity in exactly this region in the lower left temporal lobe.
New opportunities for compensating reading difficulties?
“These results mark a milestone for our understanding of reading processes,” says Fiebach. “The exact modelling of cognitive processes in the human brain will allow us to understand thinking and perception processes fundamentally better. This could reveal new training approaches to compensate functional disorders like dyslexia.” Gagl underlines this: “Combining these methods delivers a bridge technology to foster the application of insights from fundamental research in pedagogical and clinical settings.”
