Oscillatory Dynamics of Speech Sensorimotor Ensembles – ODYSSEE

Understanding the functional organization of speech processing in the brain remains a challenging issue for cognitive neuroscience and psychology. In particular, an old-standing debate exists as to whether speech perception relies on the processing of auditory information only or whether it requires mapping of sensory representations onto articulatory gestures that underlie speech production. In the last ten years, the renewal of interest for the motor theory of speech perception with the discovery of mirror neurons has inspired many researchers in cognitive neuroscience and evidence has rapidly accumulated in favour of an involvement of the motor system in the perception of speech sounds, particularly under compromised listening conditions. The degree to which this motor activation is necessary for speech perception however remains disputed. The ODYSSEE project will uncover the functional role of the speech production system in perceptual processes in typically developing children and in adults, by examining how articulatory regions collaborate with auditory regions during speech perception using state-of-the-art brain imaging technique, Magnetoencephalography (MEG). ODYSSEE particularly focuses on ‘distorted’ speech (i.e. time-compressed and natural fast speech) which may preferentially engage the motor system to constrain, refine and facilitate phoneme categorization by predicting the acoustic consequences of heard speech. ODYSSEE further emphasizes the need to examine the oscillatory dynamics of sensorimotor networks during speech perception, that is, not so much the activation of individual components of distributed neural networks but also crucially how these components dynamically interact and synchronize their oscillatory activity when we listen to distorted speech sounds. Investigating the dynamic orchestration of brain regions during distorted speech perception is fundamental to improve our understanding of the cerebral underpinnings of speech processing and will undeniably inspire future investigations on the neural bases of speech production and perception disorders.