Project summary Multisensory integration plays a central role in speech acquisition as most infants harness auditory and visual information to crack the language code. Disruption to multisensory processing in the first year of life is associated with later speech delay and language disorders. Although research in adults has identified several brain measures and brain regions involved in multisensory processing, how this process emerges in infants and how it is related to behavioral outcome, especially language outcome, is very much unknown. The primary objective of this Career Development Award is to support training in multimodal brain imaging in order to examine functional and structural mechanisms of multisensory development and their associations with speech acquisition and language outcomes in typically developing (TD) and preterm infants. Improved understanding of normal multisensory integration and deviations from normal will inform early diagnosis and intervention strategies for infant speech delay/disorders. The proposed award builds upon the candidate’s prior training in speech processing and multisensory perception, extending this knowledge into the domains of infant brain imaging (function and structure) and infant vocalization analysis. Aim 1 characterizes the neural bases of multisensory integration in TD and preterm infants and investigates brain-behavior associations in infants 9 to 12 months old (Time 1). Specifically, Aim 1a investigates cortical neural processes (obtained via infant magnetoencephalography (MEG)) following congruent versus incongruent audiovisual speech stimuli, with a focus on alpha activity in auditory cortex and gamma activity in Broca’s area. Aim 1b examines whether the MEG measures of multisensory processing as well as DTI measures of structural connectivity are associated with pre-verbal vocalization (i.e., canonical babbling). Aim 2b tests whether the brain measures and vocalization assessment in the first year of life predict speech/language outcome at 24 months. Finally, Exploratory Aim 3 directly compares these measures in preterm infants versus TD infants. Although the K01 study investigate complex multisensory speech mechanisms, the research is feasible given the candidate’s background and the available institutional resources (scientists and technology). Study findings are expected to inform theoretical modals of early speech development as well as provide the candidate pilot data for future R01 clinical brain imaging studies on atypical multisensory development in at-risk infant populations. The award will also provide the candidate the opportunity to obtain training in behavioral assessment of speech/language development and cutting-edge multimodal imaging techniques. The research performed and training provided by this award is critical to the candidate’s long-term goal of conducting independent research on the neurophysiological mechanisms of speech/language development and disorders.