MedicalResearch.com Interview with:
Stephanie Ries, PhD
Assistant Professor
School of Speech, Language, and Hearing Sciences
Center for Clinical and Cognitive Neuroscience
San Diego State University
Director of the Laboratory for the Brain Dynamics of Language
San Diego, CA
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Our study is about how we retrieve words when we speak. We routinely do this rather effortlessly. Healthy adults can produce about 2 to 3 words per second selected among over 50,000 words in our mental dictionary. However, the neural mechanisms allowing us to do so are not well known. This process relies on two complementary mechanisms: the activation of words, and the selection of words. Our study shows that these mechanisms co-occur in time: meaning one does not end when the other starts, and in space: some brain regions, such as the posterior inferior temporal gyrus, support both mechanisms sequentially.
We were able to get an unprecedented look into the neural underpinnings of this process by studying brain activity recorded directly at the cortical surface in patients undergoing intracranial EEG monitoring for intractable epilepsy. While these patients were monitored, we asked them if they would agree to participate in our study, which consisted in naming pictures for about 10 minutes. Most of the time, they agreed. We were then able to analyze the intracranial electrical signal in relation to the pictures that were named. Such occasions are extremely rare.