For the first time, an international research study has identified the regions of the left hemisphere of the brain that are crucial for representing orthography (“long-term memory”) and the processes that are active during writing (“working memory”).
The study was authored by researchers from the Johns Hopkins University in Baltimore (Brenda Rapp, Argye Hillis and Jeremy Purcell) and CIMeC – Center for Mind/Brain Sciences in Trento (Gabriele Miceli) in cooperation with SCA Studio associato in Rome (Rita Capasso), which works on the evaluation, diagnosis and rehabilitation of cognitive and motor deficits in children, adults and elderly people.
The results were published in the February issue of Brain, the oldest and most prestigious neurology journal.
The study was deemed so remarkable and original that it was featured in the journal as “Editor’s choice” article.
“The study identified for the first time the left-hemisphere regions that contain the information we need to write words (for example, to write “yacht” and not “yot”) and those that ensure that the letters comprising a word are selected correctly and produced in the correct order (so that we write “yacht” and not “yafht” or “yathc”), says Gabriele Miceli, professor of Neurology at CIMeC at the University of Trento.
Miceli explains: “The storage of written words is located in the frontal and temporal lobes of the brain, while working memory is ensured by a specific area in the parietal lobe. These findings explain a number of fundamental aspects of writing processes and contribute to better understand the links between the anatomical bases of written language and those of other linguistic and cognitive processes”.
The outcomes of the study shed light on the damage caused by brain injuries (stroke, head trauma, dementia, tumor, etc.).
“It is known - explains Miceli - that brain lesions can impair both the storage of written words and the working memory system. In order to study these two different aspects in neural terms, we have examined the injuries found in 27 individuals with dysgraphia subsequent to stroke, who suffered from deficits selectively affecting either orthographic knowledge or working memory, and those of 6 individuals with deficits affecting both sets of processes. The study used a voxel-based approach as a method to map cerebral lesions. We were able to identify the regions of the brain responsible for these processes and to find out what happens when they are impaired. Thanks to this knowledge we can better understand the neural bases of writing but also develop rehabilitation programs for people with writing disorders caused by brain injury”.
The paper’s title is: “Neural bases of orthographic long-term memory and working memory in dysgraphia”