Bharath Chandrasekaran (University of Pittsburgh)

Title: Neurobiological constraints on speech learning in adulthood

My program of research uses a systems neuroscience approach to study the computations, maturational constraints, and plasticity underlying speech perception. Speech signals are multidimensional, acoustically variable, and temporally ephemeral. A significant computational challenge in speech perception (and more broadly, audition) is categorization, that is, mapping continuous, multidimensional, and variable acoustic signals into discrete, behavioral equivalence classes. Despite the enormity of this computational challenge, native speech perception is rapid and automatic. In contrast, learning novel speech categories is effortful, and is considered a challenging computational task for the mature brain. In this talk, I elucidate mechanisms underlying how novel speech categories are acquired and represented in the mature brain. I will discuss a novel theoretical framework, the dual-learning systems (DLS) model that characterizes the neurobiology of two complementary corticostriatal streams involved in sound-to-rule and sound-to-reward mapping. In a series of experiments using multimodal neuroimaging, behavioral, and computational modeling approaches I will systematically test the DLS model. I will demonstrate that (1) neural representations of novel speech categories can arise in the superior temporal gyrus within a few hundred training trials of sound-to-category training, (2) pre-attentive signal reconstruction in the subcortical auditory system is also subject to behaviorally-relevant experience-dependent plasticity, and (3) the robustness of structural and functional connectivity within the sound-to-reward corticostriatal stream can predict learning outcome. Finally, I will discuss ongoing experiments that leverage the neurobiology of the dual corticostriatal streams to design optimal behavioral training and targeted neuromodulation interventions.

When: Friday, May 24, 1:00 pm

Where: de Grandpré Communications Centre at the MNI

Accessibility: The MNI is wheelchair accessible. Please note that the main entrance has a few steps: there is a wheelchair accessible entrance on University Street north of the main entrance. Another wheelchair accessible entrance is in the loading area behind the building: to enter the loading area, turn into the driveway south of the main entrance.  Participants are invited to make us aware of any barriers to their participation or any accommodations that we can provide. info@crblm.ca

 

Dr. Chandrasekaran joined the University of Pittsburgh faculty in September 2018 and serves as a Professor and Vice Chair of Research in the Department of Communication Sciences and Disorders. He earned his Ph.D. in Integrative Neuroscience from Purdue University in 2008, completed a postdoctoral fellowship at Northwestern University before joining the University of Texas at Austin in 2010. He is the recipient of Regents’ Outstanding Teaching Award in 2014, the Editor’s award for best research article in the Journal of Speech, Language, and Hearing Research, the Psychonomics Early Career award in 2016, and the Society for Neurobiology of Language Early Career Award in 2018. Dr. Chandrasekaran serves as the Editor-in-Chief of the Journal of Speech, Language, and Hearing Research (Speech). Dr. Chandrasekaran’s research examines the neurobiological computations that underlie human communication and learning, using an interdisciplinary, computational, and lifespan approach. His laboratory is currently supported by funding from the National Institutes of Health (NIH R01DC015504, R01DC013315, R01DC013315-05S1) and the Defense Advanced Research Projects Agency (DARPA N66001-17-2-4008).