PI Dr. Matt Masapollo recently gave a lecture at UF’s Rehabilitation Science Seminar Series, entitled, “Mechanisms in speech motor-sequence learning.”
Abstract: One of the fundamental issues in the field of speech production is how speakers map phonological units (e.g., phonemes, syllables, words) onto properly timed vocal tract articulations, which lead to an audible, intelligible acoustic signal. Much of the research on speech production over the years has focused on describing how speakers articulate individual phonetic segments and simple syllables. Relatively little is known about the brain mechanisms involved in planning and executing complex or extended sequences of speech movements. Current psycholinguistic and neurobiological models commonly propose that speakers produce speech sequences by integrating and consolidating frequently occurring subsequences of articulatory movements into cohesive units (or “chunks”) in working memory, which reduces processing load and improves motor performance. Yet there is no consensus on the mechanisms and neural substrates that support speech motor chunking processes, or the nature of the chunks that these processes operate on during serial speech planning and concurrent articulation. In this talk, I will report findings from a series of recent studies designed to elucidate the phonological working memory structures, motor programming units, and neural systems underlying this “chunking” process, using a combination of behavioral, neuroimaging, and motion capture techniques. In these studies, speakers are trained over several days to produce made-up non-words comprised of non-native consonant sequences. I will begin with findings concerning changes in motor performance related to speech sequence learning. I will then present findings that assess the specificity of this learning and its time course. Finally, I will describe the neural substrates and brain areas subserving speech sequence learning. Future directions, and potential implications of these findings for disorders of speech sound sequencing (e.g., stuttering), will also be discussed.