The right dorsolateral prefrontal cortex (R-DLPFC) in the brain plays a key role in cognitive control – decision making, memory processing, task scheduling, etc. A new study suggests that cognitive control underlies how stutterers respond to stutter anticipation (the feeling that an upcoming speech will stutter), offering new insights into how the brain processes and responds to stuttering.
“We’ve always known that stutterers anticipate stuttering, but no one has studied how the brain processes anticipation,” says New York University Steinhardt Associate Professor Eric S. Jackson, lead author of the study. “This is a significant gap in the literature, probably because anticipation is a predominantly latent phenomenon.”
The researchers studied 44 participants (22 stutterers and 22 non-stutterers) who were given the task of saying words that included expected words (words that the participants identified as likely to stutter) and unanticipated words. Participants’ neural activity was measured during the five-second window preceding speech using a brain imaging technology called functional near-infrared spectroscopy (fNIRS).
The researchers found that activation in R-DLPFC increased when participants anticipated stuttering (as evidenced by changes in blood flow). In addition, expected words were associated with reduced connectivity between the R-DLPFC and the right supramarginal gyrus (R-SMG), another part of the brain in the cognitive control network.
“The results show that R-DLPFC is upregulated in response to expected words, and that anticipation is associated with destabilization in the wider cognitive control network. This work lays the groundwork for developing a brain-based explanation for this crucial phenomenon, and may also have important clinical implications related to targeted neuromodulation as a component of stuttering therapy,” Jackson said.
The study, conducted in collaboration with Yale University, is published in the journal Neurobiology of Language.