Project Summary/Abstract Recent studies have increasingly linked stuttering to aberrant neural network structure and function in cortical speech motor and auditory areas, and connections with subcortical structures. These networks support fine- grained control of internally timed and precise motor movements required for fluent speech production and overlap with a rhythm processing network. Stuttering is hypothesized to involve poor auditory-motor integration, a failure of synchronization between auditory and speech signals in the brain. One step towards novel, neuroscience-based treatments derived from a thorough understanding of this abnormal neural circuitry is first to measure auditory-motor synchrony in adults who stutter (AWS) and fluent speakers. We will use an innovative spontaneous synchronization of speech (SSS) task shown to index temporal dynamics of auditory-motor integration in fluent adults via implicit speech synchronization. Starting from the hypothesis that poor auditory- motor integration may be a causal and treatment-relevant pathway and moving towards new intervention development, our next step and overall objective of this study is to use the SSS task to investigate temporal dynamics of auditory-motor integration in the context of speech production people who stutter. The central hypothesis is that AWS and CWS will exhibit poor implicit speech synchronization compared to fluent peers. The rationale of the proposed study is if AWS and CWS show poorer implicit speech synchronization compared to fluent peers, this will constitute further evidence that abnormal auditory-motor integration is a core component of stuttering. We will test the following specific aims. 1. Compare implicit speech synchronization AWS and fluent peers. We hypothesize that AWS will exhibit poorer synchronization than fluent adults. 2. Compare implicit speech synchronization with explicit speech and non-speech synchronization in AWS and fluent adults. If AWS have a general deficit in synchronization, they will show poorer synchronization in speech and non-speech tasks compared to fluent adults. If AWS have a selective deficit in synchronization that is limited to speech, they will show poorer implicit and explicit speech synchronization than fluent adults. If poorer synchronization in AWS reflects an implicit effect that can be overcome with explicit synchronization instructions, they will show poorer implicit, but not explicit speech synchronization, compared to fluent adults; no difference between AWS and fluent adults is expected in non-speech synchronization tasks. 3. Compare implicit speech synchronization in fluent children and CWS. We will extend the SSS paradigm to (a) establish feasibility and response distribution in fluent children and CWS. The expected outcome is a better understanding of how temporal aspects of auditory- motor integration contribute to developmental stuttering. Ultimately, we aim to identify those for whom synchrony focused tre...